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MG TD TF 1500 - Head Gasket - More in Hope than Expectation...

I am pretty sure I have a leak in my head gasket :-(

I have been recently getting a lot of white 'smoke' occaistionally on start up plus some rough running. Seemes to clear up but has returned on and off over the last few uses of the car.

Was bad yesterday but again cleared after a bit of a run. I stopped for petrol. On start up I had a huge cloud of smoke out the back. The car was hot.


I checked the readiator cap today- a little greasy gunge. I also checked the oil filler cap - see pic. It has a thick coating of emulsified oil&water mix. You might be able to see faintly some whisps of smoke ( oil or water I can't quite tell)

What I found odd is that the car hasn't been blowing white smoke all the time. I popped some redex petrol additive in last night just in case it was just coking from short runs I just took it for a quick run and it was fine on start up and all through the run. Exhaust was really clean.

I did recently upgrade to a 7lb cap on the radiator. I replaced all the rubber hoses to be sure with the increased pressure. Could this change in pressure have been enough to pop something ?

I was hoping it was just condensation in the exhaust but the amount of smoke and the emulsion in the oil tells me head gasket. Do you get intermittent failures in head gaskets ? I can't see how...

And here is the hope bit... is there any point in checking and tightening down the head or do I have to just bite the bullet...

All suggestions welcome :-)

Dave

MG TF 1955 1500


Dave Moore

Changing out the head gasket is no big deal. You will also new side cover gasket since the head is the top edge of the side cover opening. Don't forget there are banjo washers for the top oil line fitting.

It is a perfect chance to go through the valve guides, the seats, the valves and the rockers.

You should be only down a week, maybe a bit more if the parts are slow to arrive from one of he usual suspects.

warmly,
dave
Dave Braun

Good garages have a gas tester kit, or you can buy your own for about $60 that will check the radiator coolant for presence of combustion gas. This is done easily and quickly , by just inserting the tester in the radiator cap opening. The clear tester has some type of chemical which will change color if the combustion gas is leaking through the head gasket.
Dallas Congleton

Often the cylinder that's getting water will have a very clean spark plug.
J E Carroll

Dave,
Bite the bullet and change it,,,, It might be that as the engine and head get hot and axpand, it might somewhat stop the leak,,, but it's not going to get better all by itself,,
If the fact that it sometimes doesn't show the telltail whitish smoke and you chose to ignore the problem,, the head gasket could (and probably will) fail at a very inoperture time,, like maney miles away from the garage,, or in heavy traffic,,late at night etc,, change it now,,,,,, and as Dave says,, go through the valves seats, rockers,,etc Might even want to clean up the carbies as long as they are off also,,,

SPW
STEVE WINCZE

But keep in mind, you need a head gasket/side-cover gasket, first....The "might as wells" can eat you alive....
I just wanted tighter pedals, and ended up doing a frame-off!
Good luck.
Edward
E.B. Wesson

I have stopped small head gasket leaks by re-torque-ing the head. and I believe that the head expands more than the studs as temp increases, stopping some leaks. Aluminum expands more than cast iron so temp has a bigger effect in that case.
chuck
cj schmit

Ten bucks says it is between 2 and 3. Thinest spot on the gasket as the two cyl. are very close. I would also recommend that you buy the Tom Lange gasket set. somewhat expensive but they last forever and dont leak. Your rad cap looks exactly like mine when I blew my head gasket..
Tom Maine (TD8105)

Thanks guys for the advice so far. Any comment on wether switching to the higher rated cap is a possible cause ?

Just interested since swapping back will make no difference now the damage is done...

I haven't any experience with dismantling or working on a head ( I did take one off a mini 20+ years ago for a different reason). I'd be reluctant to start working on it. Not afraid of tackling most things with the manual at hand but my guess is there is a lot of things that need to 'feel' right when re-assembling the head. I can fix things if they are broken - not so good at judging wear or fit - needs more experience than courage and a good manual alone :-)

The engine was recently rebuilt and was converted to run -unleaded at the time- only a couple of 1000 miles on and was running sweetly up until now. My guess is it is good.

If I do it myself it will be a straight off, clean any obvious coking and straight back on again job...I hope :-)

I see some discussions in the board archive about different types of head gaskets depedning on head and block combinations. My car is a late TF with the original engine - anything I need to be aware of when ordering or am I at least going to get lucky with their only being one parts option :-)

Dave
Dave Moore

Dave - don't be afraid of tackling a head gasket. It soulds major, but is really quite easy. Remove the bonnet top, distributor and top radiator hose, loosen the side cover, remove the rocker gear and pushrods, carbs and exhaust, oil line and then the head nuts. Pull it straight off and the head's done! I remove the head studs and use a small stone to go all around the top of the block, smoothing the threads and showing where there might be a low spot. Check the head studs for stretch,the rear head cover for rust-through and, shiny spots on the pushrods (shows a bent pushrod), and the condition of the engine steady rubbers and engine mount.

Parts you will need include front and rear gaskets, head gasket, new rocker bolt tabs, valve o-ring seals, etc. See my webpage mgtrepair.net for information on high-quality silicone valve cover and side cover gaskets - this is your chance!

Just be sure you have a good machine shop ready to check the valves and head flatness, and be prepared to have the rockers repaired, bushings and shaft replaced, as well. My guess is that 3 weeks down is more realistic, as sub-contractors are required.

And don't hesitate to ask for advice or encouragement - we've all been there! Do find out who can rebuild rocker gear over there.
Tom Lange
MGT Repair.

t lange

I agree that changing the head gasket is relatively easy. Actually it's easier than a Mini because that has the annoying little hose between the head and waterpump...

Like Chuck I've stopped a small leak by retorqueing the headnuts on my MGB. Maybe this 'freshly rebuilt' engine needs only that (and resetting of the valve clearance afterwards).
Willem vd Veer

Sorry, I missed that the engine had been recently rebuilt. All the 'be prepareds' I note are probably not necessary. A good doctor should always listen to his patients.

Tom Lange
MGT Repair
t lange

I should mention I just did all this on a TC. We started by removing the bonnet. However on a TF I know people who remove the right hand wing to make the job easier (namely to loosen and pull aside the carburetors and intake manual intact, and pull away the exhaust manifold.)

With the head off, inspect the surfaces carefully for cracks. If you suspect you see one, take the whole thing to an engine shop with the rocker assembly, and have it inspected by experts.

Inspect each head stud for stretching in the threads. If you put the studs on a mirror, even an untrained eye will detect a 'necked' damaged thread form. Do not reuse any that are stretched. Adhere to torque values when reassembling. If someone overtorqued things when reassembling the engine, the studs might have stretched and lost their ability to 'spring back' during expansion and contraction. The torqure values should stretch the stud just short of permanent deformation.

hope this helps,
dave
Dave Braun

Chuck,
How is aluminum getting into the mix????
STEVE WINCZE

I should perhaps mention that i sell very high quality head studs made by the racing supplier ARP. See this and my other products at mgtrepair.net

Tom Lange
MGT Repair
t lange

Dave
There's a saying over here, "Luck of the Irish to you." I wish you luck, but I also like to have a little more than luck going for me. Chances are you may have a leaking head gasket, a pretty new one though. Some mechanics routinely retorque after a period of running. Me? I'd put a compression gauge on it to find clues to what & where I'm dealing with. Before I do a compression check, I break the plug loose a few threads, retighten them and then run the engine. Your fresh rebuild probably doesn't have clumps of carbon, but I have checked compression, run it and then double checked compression to find amazing improvements in readings. This was a recommendation from Gus's Garage in Popular Science a half century ago. I was maybe 10 years old when reading that, and haven't forgotten it. Anyone else recall? Carbon can lodge in between the valves & seats and give a false low reading.
I have had more than my share of burned gaskets between 2 & 3, even a solid copper gasket, but that actually has more meat than 1 & 2 and 3 & 4. Trouble is, there are 2 exhaust valves side by side right there and that is THE HOTTEST SPOT in the engine.
Check the compression looking for a weak point, retorque your head, and then recheck the compression. When retorquing, watch for any stud that doesn't tighten abruptly. If you keep cranking and the nut doesn't torque down like the others, you may be stretching a stud OR stripping threads out of the block. Been there, done that. I plan on installing helicoils in our block on the upcoming rebuild, and then overtorquing to a higher value.
Something I did as a kid, was to paint the head, gasket & block surfaces with aluminum paint. Now with the Hondas I've been playing with, the aluminum paint is flowing again.
I'll bet if you pull your head with only a few thousand miles, you'll find a good head gasket.
"Luck of the Irish to you."
JIM
JIM NORTHRUP SR

Thanks guys.
At the weekend I am going to start with checking the existing torque values and take it from there.

If it has to come off I will organise with the mechanic to do it with him. He is a semi-professional retired guy and MG midget racing enthusiast. I think he will oblige.

This way I can learn and fix at the same time

Dave
Dave Moore

I worked on the head today. Very odd.

I set my torque wrench to 50lb/foot (67.8 NM) and they all passed. I cranked it up a bit. Nothing. Cranked it up again. Nothing. At 59lb/foot I stopped.

So I must be doing something wrong or the wrench is off.

Lets asssume the wrench is ok. Here are some factors I'd like your views on :

The engine was cold and the day was cold ~8 degrees C. Warm it up to 'room temp' of say 20 degrees ?

I started with a tightening. Should I have backed off the nuts a half turn first to get them moving?

In order to get around the tappets and cam I used was coming at a very slight angle?

Since I am using an extension bar on the wrench to clear the cam and tappets does this affect the way the wrench registers the torque? ie it was calibrated with the socket directly attached...

Cheers

Dave


Dave Moore

>So I must be doing something wrong or the wrench is off.

It may very well be off. The micrometer style click-wrenches (if that's what you have) go out of calibration very quickly. In a production environment it is often required that those wrenches be recalibrated every six months, maybe even more frequently. Make sure when you store the wrench you turn the adjustment to the lowest range of the scale (but not all the way loose).

Beam types (pointer & scale) rarely go out and can be recalibrated by simply realigning pointer to zero. Split-beam (like a clicker but less common) also rarely go out. But the micrometer clicker type is the most common.

>Should I have backed off the nuts a half turn first to get them moving?

Yes. And the threads should be oiled...

>I am using an extension bar on the wrench to clear the cam and tappets does this affect the way the wrench registers the torque?

Not if it is just a straight extension. Some applications require something like a crow's foot that offsets the centerline of the fastener from the centerline of the torque wrench head. In that case it WOULD affect the torque reading. (But there's a trick for avoiding that....) I'm assuming you're not using a crow's foot.

I think the main thing is that you didn't first loosen the nuts. Moving friction is always lower than static friction, so loosen the nuts then bring to torque with an even, steady, continuous pull.

All that said, I don't think this is something retorquing will fix.

HTH!
Rob Edwards

Thanks Rob for the tips. It is a micrometer clicker. I stored it right and used if before hand on some other bolts with a higher torque to 'exercise' and lubricate the mechanism. I'll assume it is ok for now.

I'll try backing off and the torquing up as you suggest.

As you say probably isn't a fix unless the bolts were under torque to start with.

More in hope than expectation :-)


Dave
Dave Moore

rob, i am away from my service manual, so i will ask..are you sure the nuts should be lubricated prior to torqueing..the only fasteners i think of that require lube are stainless to prevent gauling. every torque setting i can think of takes a big reduction for a lubed torque setting. regards, tom
tom peterson

Hmm. Interesting.

Since half the head bolts are within the rocker cover and half are outside there is a mix of dry and wet bolts to start with...oil will have seeped into the 'internal' nuts over time even if they were dry assembled first.

I did a quick search and came up with this table


http://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

Bascially says 30-40% reducution in torque with engine oil... which I would guess actually is a reduction in the friction applied to the nut when moving but would translate into a higher final level of torque on the bolt.

Elsewhere I have seen lower figures of around 15% increase in final torque.

There appear to be two sets of guidance. For torque to yeild bolts no lube recommended. For ' standard' bolts light engine oil.

Since a primary goal of all this is even pressure on the head I will soak in oil the nuts bolts outside the rocker cover for a while so that at least they match the bolts inside.

I will clean up the threads. Back off each bolt in sequence half a turn or sojust to get the nut moving then torque up again.


Dave

TF 1500

Dave Moore

So. 'worked' ?

Ran the engine briefly so it was 'room temperature'.

Cleaned off the paint from the external bolts.

Dropped on some 3in1 ( light multipurpose oil).

Lossened the bolts a fraction got them moving.

Set the torque wrench to 50lbs tightened up.

Set to 55lbs and gave them a nip. Not all moved again.

One or two were 'looser' when I started. The two central bolts (1&2)in particular had their tension relieved very quickly > .25 of a turn. So may have been the source of my trouble.

I will monitor over the next while.

I was wondering about the water in the oil. I cleaned up all the emulsion on the inside of the rocker cover and I don't think a lot of water got in.

I topped off the radiator withabout half a pint I'd say.

I will of course replace the oil soon. But didn't want to do that until I have either solved the problem ( or not)

Is it ok to continue to use?

Thanks.

Dave
Dave Moore

Congratulations, Dave. A satisfactory conclusion to a thread I've been following since the original post.

I've not the technical skill to advise you whether it's OK to continue to use or not (I'd have thought it was, but I'll leave that to others). But it does look like another success for this Group working constructively through a problem, by pooling experiences and advice.

The Group has saved me quite a bit of head-scratching over the past 3 or 4 years, one way or another, and I don't get to thank them often enough.

Regards,

- Tom.
Tom Bennett - 53TD 24232

>I will of course replace the oil soon. But didn't want to do that until I have either solved the problem ( or not)

I'd change it now just to be safe. The cost of several litres of oil pales in comparison to the cost of a new crankshaft! A water/oil emulsion is a bad lubricant.

How does the oil on the dipstick look?
Rob Edwards

Oil on the dipstick looks good as did the oil over the rockers etc.

The emulsion appears all over the inside of the rocker cover where I guess it gets sprayed. There was a pool of this then on the inside lip of the cork gasket where it ran down the rocker cover and gathered.

Dave
Dave Moore

No more white smoke. Recorded the fluid level in the rad - looks exactly the same. Car running smooth so decided to change the oil

Put in engine flush and drained the oil.

Cleaned up the rocker cover.

I am still getting an emulsion on the inside of the rocker cover.

Will there still have been enough water in the residual oil to cause this- it will have sunk to the bottom of the sump I guess ?

The engine oil looks great on the dip stick.


Dave
Dave Moore

Could the water part of the emulsion just be from condensation inside the rocker cover when the engine cools off? Then when it's started, there's plenty of oil splashing around to create the emulsion.
Just a thought. I seem to remember seeing the inside of a rocker cap look like your original picture.

Al
54 TF "Emma"
A W Parker

Now: a very old trick to learn if there is any residue
emulgated in the sump oil .
Put the dipstick in , make sure it reaches the bottom
Take it out and hold the stick almost level.
Now take a cigarette lighter and lit, heat the bottom end of the dipstick and wait for the oil to heat up
If during that process tiny sparks become visible ( actually water boiling and want to escape their oily environment ) You can bet you have water in the oil.

I know of more scientific methods but this give you a start to further investigate
Gerard Hengeveld

Dave-
A teaspoonful of water makes a lot of mayonnaise!

It takes, at a minimum, 20 minutes driving under load - not idle or sitting at traffic lights - to begin to get oil temps up. Any moisture in the oil or engine will not begin to clear until until oil temps are near 200F, at least on some surfaces, like the top side of the head - the only thing that will get that hot normally. All other surfaces will be much cooler, until the warm oil circulating heats them - including the layers of sludge on the lower block and sump sides, which might never get warm in winter.

If the engine breather system is not functioning, it is far worse - and a road draft system such as these cars use CANNOT function sitting still.

This is why short trips, idling, stop and go traffic are considered as "severe service", requiring frequent oil changes. If you have a low thermostat, or none, it gets much worse. Cold and damp weather likewise - I made an insulated shield over the top of my Austin 1300, which created rocker cover sludge in severe winter weather, even though I was routinely running 200 miles nonstop at about 75mph averages. And that's with a 190F stat, 90% of the grille blocked, and the transverse gearbox heating the oil.

Failing a hard run for 50 or more miles, your best bet is to put an electric heater under the sump with baffles to get the heat going up under the engine. Remove the oil filler cap or the rocker cover and let it cook.

FRM
FR Millmore

Thanks guys.

I'll try your test Gerard and report back


I hadn't thought of just water condensing from the astmopshere on the indside of the rocker cover as Al suggests.

What ever happens I'll take the rocker cap off after each run for a while and let the 'steam' out.


Dave
Dave Moore

No sparks Gerard :-)

Thanks for the tip.

Dave
Dave Moore

My pleasure,

Gerard
Gerard Hengeveld

So gents ( and ladies... ?) car has been running really well since this thread closed but my hopes that were momentarily fulfilled have been dashed.. :-(

I have cured the water getting into the fuel, don't seem to be getting any into the oil...but I am now getting exhaust gas into the water...


I noticed a bubbling sound coming from the rad and then most recently there was pressure being relieved by the cap ( new 7lb cap).

Started the engine cold with the rad full to the brim and I immediately started getting bubbles. So looks like I have made better - but not completely fixed the head gasket leak by the simple expedient of tightening the bolts down.

Off comes the head.

Before I start I would like some advice.

I will need a new gasket

Are the Moss parts good or do I need to look further afield ? I am in Ireland so any of the UK suppliers are accessible - but will order from the US if there is a consensus. I don't want to have to do this again :-)

I have also seen discussion about round vs oval holes for the water passages in the head gasket -is this relevant for my 1500cc engine (made 1955) ?

Thanks :-)

Dave.

PS great to have a project to look forward to in the new year

Dave Moore

1500 has exclusive gasket due to larger bore.
J E Carroll

You should have a round hole head.

Jim
Jim Neel TD28423

Did you do a compression test? Take a few minutes and do it! That can give a solid clue towards the area of concern.

Use a torque wrench to undo the head nuts and check the values. Low readings could indicate studs yielding or possible threads giving up in the head. I plan on redoing all head threads with helicoils on upcoming rebuild, since some nuts could not come up to torque- some just kept screwing on and on, giving the feel of stripping threads or necking down studs, rather than tightening down.

After you remove the head, you may find whatever traces of leakage from bore(s) to water passage, then compose a plan. With a conspicuous leak as you mention, you should find something.

IF YOU DON"T FIND ANYTHING OBVIOUS on the head, block or gasket surfaces, as I said before, I'd clean with acetone and lay on some aluminum paint to all surfaces (or copper based gasket sealant as others suggest) and try it again. It the gasket isn't burned, it has life in it. I'd bet on a painted up sandwich with slightly used gasket, as opposed to dry installation with new gasket.

My Christmas present worth 2 pennies (maybe)!

Please keep us up-to-date... that's how we learn from experiences!

JIM
JIM NORTHRUP SR

Following up on what Jim said above: If you have access to a differential compression tester as normally used on aircraft piston engines, you may be able to isolate which cylinder is the offender.

Lacking the differential tester, a simple adapter to put compressed air into a spark plug hole will do. Crank the piston to the top with the valves closed, place in 4th gear with the brake set and plug the compressor in. You should be able to find the one leaking into the coolant and also hear leakage past the valves and rings if they're leaking.

I still have some adapters I made when I was a kid. I knocked the ceramic out of an old spark plug and welded a quick connector to it. I used them to hold valves closed to replace broken springs, over-revving is tough on them :-)
J E Carroll

Just to update on this thread I just drove the car back from the repair shop.

As planned the mechanic let me work with him on it so learned a great deal.

The gasket was blown around the front right hand stud and perhaps the one beside it . No 7 and No 3 on the tightening sequence. Water was getting into the cylinder - the plug was lovely and clean compared to the rest...

We removed the exhaust studs - meant we could just lay the carbs and manifold back an inch or two. Plenty of room to lift the head.

There was a small warp and imperfection on the head itself. We had it skimmed.

Reassembly was straight forward. The gasket was put on dry. I did ask as Jim advised otherwise above... he and manual both said no.

Troqued up to 50ftlbs. We had water straight away leaking out of the head jointbelow No8 stud (last rear carbie side) and coming up through the nut on No 4 ( the one second from rear on carbie side).

Scratched heads. Torqued to 55ftlbs. Stopped the leak on No8 - No 4 still bubbling up water.

All others fine.

Ran the engine up to temp. Water lestened and slowed right down. Still some.


Stratched heads.



Could be a small crack in the head ? There was nothing we could see or the machinest noticed.

Decided to leave it and see if it settled.

Considered putting a stop leak product into the rad.


Any other suggestions ? ( other than perhaps Jim was right after all and we should have dressed the gasket...)

Dave

Dave Moore

This is what I use unless the gasket type should not have any sealant - usually cast iron blocks with aluminum heads. Those metals expand at different rates so the gasket actually allows them to slide without loosing a seal.

For cast iron blocks and heads with a steel or copper or composite gasket I've always used a good sealer. I don't believe that aluminum paint is a good substitute.

http://www.permatex.com/products/product-categories/gasketing/gasket-sealants/permatex-copper-spray-a-gasket-hi-temp-sealant-detail
J E Carroll

Dave, thats really puzzling......Hopefully someone has a clue!
So, before you got water in a cilinder and exhaust gas in the water. Now water is leaving at the side out of the gasket and upwards along a headstud.
You did examine the head but did you also examine the blocks top?
Huib Bruijstens

I realize it's too late this time, but when I have the head and head studs off, I always run a small stone in small circles around the top of the block, to show where low and high spots are. It's surprising how much better the block looks after this process, and how much smoother it is all over.

Also, the ARP head studs I sell are safely torqued to 60 ft-pounds. See mgtrepair.net for more information

Tom Lange
M<GT Repair
t lange

'run a small stone in small circles '

I am trying to understand this. What do you mean by a small stone Tom?

Dave
Dave Moore

I have a small Arkansas carborundum grinding stone, very fine grain, about 3" in diameter, that I oil and run in small circles over the entire top surface of the block.

Sorry if I was not clear.

Tom Lange
t lange

Dave, this may sound like a silly idea but are you sure that the head nuts are not bottoming out on the stud threads before they can completely pull the head down to the gasket and block deck?
Cheers, Hugh
H.D. Pite

Dave and Hugh - I apologize for plugging my products so shamelessly these days, but I may be able to help if Hugh is right. My high-quality head studs will improve matters - I have added extra threads to the studs to compensate for heads that have been re-surfaced a few times. Washers under the head nuts are NOT recommended.

See mgtrepair.net for more info.

Tom Lange
MGT Repair
t lange

Dave, Hughs suggestion really makes sense to me because in one way or the other it appears that the torq is not reaching the gasket.
I looked up an old stud and the length of thread on both ends differ: 20 mm and 15 mm. To my understanding/remember, the short thread goes in the block, leaving enough thread for the bolt. But, if done the other way with the short thread "upstairs", this is just enough/not enough for the nut to hold. Screwing the nut completely down on this short end, the amount of thread popping through on top is just about the same as on my headstuds in the car.
So, if those studs have been placed with the short threads up (15mm) than one would fasten the nuts and not be able to notice that the just come to the thread end as Hugh suggested.
Huib Bruijstens

Just throwing in my 2 cents in this very interesting thread. When rebuilding an engine, any engine that has the original head studs in it, I replace them with new. I don't even check them for stretch, I just trash them. To many years of hot and cold changes the composition of metal to the point fatigue sets in. I'm not a metallurgist but experience has told me that when rebuilding an engine, all torqued bolts/studs/nuts get replaced with new and that includes the washers. Cheap insurance. Oh yes, I always install my studs dry in a casting then lube and use a wet setting on torquing the nuts. JMHO. PJ
Paul sr

Been there, done that with 280Z and my TD over the years, very frustrating. One of the first Taiwan Moss headgaskets leaked like a sieve 20+ years ago. While it could be somewhere in the thread above, you should replace the studs, as it is common for them to stretch. Also, when they are removed, the metal on the block tends to pull up where the threads enter the metal. You can dress that down with a file, and/or using a tapered stone or cutter of some type, slightly recess that area. Did you visually check block/head for cracks? Or magnaflux the head? Just wondering. I also strongly suggest the copper Permatex type gasket spray. George
George Butz

George Butz, Did you visually check block/head for cracks? Or magnaflux the head?

I thought of the same thing George, but also thought that should be a normal check when a head is pulled after a problem. I guess everyone doesn't do that. PJ
Paul sr

Any time I replace head studs in any engine I chase the block threads clean after lightly dressing out any lifted top threads and then install them with Permatex thread sealer. I use ARP's thread lube on the nut end as generally engine torques are lube torque values and I think they have a superior product. ARP sells a thread sealer that looks suspiciously like the Permatex product. Somewhere around the shop I have some installation instructions that came with a SBC stud kit that essentially say the same thing; perhaps Tom supplies the same with his studs.
J E Carroll

All good thoughts gents,

We did examine the block and head for any imperfections or cracks. The only thing was a tiny divot well away from any channels. Not sure what could have caused it but it was still there after the skimming.

Not sure what magnaflux is..

Didn't use thread sealer or any dressings.

I am pretty sure we put the studs in the right way but they could have stretched either way.

We used assembly lube on the threads and nuts.

Taken a whole things like thread sealers/ gasket dressings, alluminium paint are all 'additives' to the process.

What do you think about the stop leak additive - the brand recommeded its Nova Seal. BARs is a readily available brand here.

Seems to me that much of the best practice (other than replacing the studs / checking for stretch in the block) are compensation for imperfections...

Nobody commented on this - but it is the only thing I can do without pullling it all apart again...

:-)

Dave
Dave Moore

Dave

If you check my threads you will note I have been down the same track as yourself with bubbles in the radiator.

I dont doubt the abilities of your mechanic however I struggle to comprehend why when your head was removed to replace the head gasket the head was not crack tested. If this was done it would have removed one area of doubt in the rectification process.

The engine that I received when I purchased my TF was documented as being fully reconditioned. This was proven to be a joke, No4 piston had been driven into the block with a hammer, new valve seats had been inserted into a head that was cracked at a minimum of 4 places.

This is very critical but I am afraid there are practicing mechanics and there are "muganics".

I finally have a positive outcome with my motor after new No4 piston and rings, block work to provide clearance to fit No 4 piston, fitment of rear and front oil seals, replacing the head with a reconditioned crack tested unit, copper head gasket installed dry and fitment of Toms ARB head studs torqued to his specs.

I trust you can achieve the same outcome.

Graeme
G Evans

GM has an issue with a series of 5.3l heads cracking. I own such an engine and indeed have a cracked head. After pulling the valve cover and discovering it I didn't have the time to replace it due to my schedule. I added some Bars-Leak in hope of a temporary fix. That was three years ago and it's holding fine. I've had no problems with clogged heater cores or anything like that so that's the way it's going to stay.

ZERO leaks!
J E Carroll

Dave, if it were my engine I would put washers temporarily under the head nuts and see if you still have a leak after torquing. If this cures the leak then deal with the stud length.
Cheers, Hugh
H.D. Pite

Hugh, that would be my way to go also.
Rereading Daves reports, I found this remarkable one from october 28 2012: "The two central bolts (1&2)in particular had their tension relieved very quickly > .25 of a turn."
It a nut is blocked at a threads end, this would be what happens. If a nut is elastically stretching a lenght of a stud, the tension would flow away more gently whilst turning.
If a crack in the head would be the devil, than the point of water exit would have been more stable during Daves observations.
Huib Bruijstens

Err... you will never guess what... but the leak stopped...

I started her up today and let her warm up. Not a drop.

I can't explain it.

I'll keep an eye on it for the next while and for any mayonaise developing in the oil.

Weird.

Given the discussion about the stud lengths I looked at them while doing this. They are not even in length - ie some are more proud of the nut that others.

The suspect one is actually one of the 'shorter' ie would in principal have more thread left to use than the others.

Is this difference in protrusion common - say quarter inch ?

would indicate quite a lot of streching or uneven threading into the block...

Dave

Dave Moore

Sounds like some are rightside up and some are upside down.....
Rob Edwards

I agree with Rob. Sorry to say, but I would pull the head again and make sure all the studs are inserted the right way. I would re-read ALL the threads above, and treat the engine accordingly (clean all threads and holes, smooth the block, check all studs for stretch and proper insertion, etc.). The last thing you want to do is blow a head gasket when you are miles of anywhere you can replace it.

Tom Lange
MGT Repair
t lange

Gents I haven't had much of a chance to drive the car for a while but though I would update you all.

I didn't pull the head. I talked it over with the guy who helped me. He (and I with him) did as good a job as we could. He is sure the studs are in the right way. They may have been different lengths to start with. Who knows at this point.

Anyway long story short I tried a sealer product. He had recommended 'Nova Seal' I couldn't find it but picked up a bottle of K-Seal on the recommendation of my local parts shop ( good guys).

Supposed to be a lot better than the normal Bars product. Double the price too.

I haven't had a drop of water out since. No mayonaise in the oil. Looks solved. Now I don't like adding these kinds of products as opposed to 'fixing' it...but it was a whole lot easier.

I am back on the road. Engine is running sweetly.

I also managed to fix and calibrate my temperature gauge ( separate thread :-) ). So I won't have the overheating without warning that probably got me in this fix in the first place

I have more expectation than hope now :-)

If I ever do this again I am getting a full set of Tom's studs...

Cheers

Dave
Dave Moore

Dave, i am A little late to this thread...but my 2 cents is the issue with block sealers is they do not know the difference between an outside leak or small spaces between internals. I believe they are a temporary fix at best..at worst they block internal openings restricting coolant flow and decrease the cooling capacity of the system. Just think of all of those small tubes and openings in the radiator...makes me shudder, but I am against all "pour in a can" fixes.
I am happy to hear your car is now drive able. Regards, Tom
tom peterson

Tom,

I've had the occasion to examine a radiator from a car that had Bars-Leak in the coolant. The radiator was an aluminum core, plastic tank type. The tank is held on by a steel band that is crimped over the core and tank.

In this one the steel had corroded so bad that it let the joint open up. Bars-Leak was added and was holding until the steel totally rotted away.

Since the radiator was junk anyway, I cut the rest of the steel crimps and released the lower tank. There was no blockage of any sort that I could detect in the core. It seems the stop leak effect only takes place when the passage is microscopic and not radiator tube size; I don't know the exact mechanism.

As I noted above, I have been using it on a cracked aluminum head for some time with no problems either with heating or cooling.

Based upon my observation and experience I really wouldn't have any qualms about using it although frankly I'm surprised that the gasket is leaking.

In the case of the leaking radiator I just spoke of, I came in after the fact. I would have just replaced the radiator right off as most seem to be inexpensive.

Jim
J E Carroll

This thread was discussed between 22/10/2012 and 22/04/2013

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