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MG MGF Technical - Coolant Gone

Nice cold foggy morning, driving to work.

Heater just blowing cold air, even after water temperature up to halfway...strange.

Stopped at light, water temp crept up to max.

(engine temp looks ok, at about 80-90)

Moved off, water temp dropped.

Stopped, water temp increased.

Parked in car park, and coolant left, although a lot of pressure in the system.

Guess its a call-out to the RAC and back to the garage.

paul weatherill

Uh-oh :o(

Very sensible to get the garage to collect the car Paul. Hopefully a simple coolant leak from the rad or coolant pipes, but I guess that may be too hopeful.

Any evidence of the dreaded mayo in the oil?
Rob Bell

Now the car has been sat a while..

noticed all the lovely bright green coolant leaking out of the radiator.

RAC off to get a low-loader.

Fortunately, was very foggy this morning so I was keeping the speed down.

Engine temp didn't rise above 90, so hopefully no damage there.

Fingers crossed.

(Haven't checked for mayo.)
paul weatherill

Transient over heating will probably cause no problems at all with the engine. Sounds like a problem with the rad or its connections, so a solution should not be too painful to bear.

Fingers crossed Paul!
Rob Bell

Or a broken bleeding screw, on top of the radiator.

I do learn, you see ;-)


A bleeding screw and a bleed screw are slightly different - will explain next time we meet :-)

Ted Newman

>>Or a broken bleeding screw, on top of the radiator.

Me too Erik. I had this problem just a couple of weeks ago on my '98 VVC. The coolant was leaking from around the bleed screw head. When touched the head of the screw just fell off, having completely perished. Such a small problem caused quite a large coolant loss.

Paul, whatever the cause, take care to bleed the system properly if your coolant loss was significant enough to empty the expansion bottle.


Funny you should mention this,

Obviously, bit difficult to find the exact position of the leak without getting my hands dirty, but on brief inspection, it does look like it leaked from the upper (passenger side) corner of the radiator.

As far as bleeding it properly, its in the hands of the dealer, so...lets just hope.

paul weatherill

Dave L - that's exactly what happened to Erik's car in Berlin on last year's Treffen, and unfortunately it was my hand on the spanner when it decided to fall apart !

.. still after a machined 15/32" or M12x1.5mm metal screw for replacement.
With cone insert bolt like at the heater bleed location or like at the brake cylinders.

mike ? ;)
I vote for one. Aluminum, anodised or much better made from SS.
Dieter K.

Sounds like a good idea to me Dieter. especially after last year's Treffen... :-O

I think the problem with the bleed screw is that it is plastic, and as such if overtightened (by one of your more common varieties of MGR Grease Monkey), then it shears the thread from the bolt loosing pressure on the rubber washer and causing a leak. Poxy bit of design if you ask me, especially as it is an imperial sized plastic bolt! You can imagine the problems we had trying to source a replacement in the middle of Germany on a Sunday...

Scarlet Fever

Dave, you also wrecked your own caliper bolts as well mate.LOL. Maybe you should take the title from Dieter, Master Of Disaster:-)

>Poxy bit of design

*g, the mad rubber ring is one problem. The other is the spanner width 15? and at last the rough craftsmen power arm.
Not sure but I assume you can built torque of about 80Nm with a 15mm spanner.
The guy who changed coolant at my car yesterday used to use a long *T-form* wrench with fixed 15?mm socket. Accessed with the finger tips. ;)

>source a replacement in the middle of Germany on a Sunday...

LOL, though I had two options on that sunday morníng. But both would have resulted in another 20 miles ride back through Berlin in east direction. 2.5 hours loss and the Teflon wrap idea with Michaels slot file works was much easier :)
Dieter K.

Problem here as the radiator can is also plastic. Make a bleeding :-)plug from stronger material and you end up with no threads on the radiator.. a more expensive and difficult problem in the middle of Berlin;-)
How about a machine grade nylon ? Anybody want one and a spare?lol.Maybe I just take some on the Treffern
swap for some large German beers ;-)
mike(still a member)

Had easy bleeding in my mind, but who cares.
Contract signed.
Dieter K.

Well warranty are replacing the whole radiator, so hopefully get a nice new bleed screw with it.

Replacing coolant pipes as well, but personally paying for that.

Just need to wait, and pray that the dealer takes time, and bleeds the system properly.

paul weatherill

What dealer you taken it to, Paul??


Bump !!

and new (or not?) theory.

I had some emails today with an old friend about a may be similar case. Dunno, but I think he will join the thread later. He is a regular at the german Forum since we started 4 years ago. Well experianced MGF owner and electric engineer. So I think he knows what he's talking about.

His car had a HGF in last year (2.000 km ago).
Now he gets frequently engine overheatings and coolant 'blow off' sometimes.
It happens almost when driving long curves after long rides.
Coolant temp raises within seconds, heater blows cold suddenly. This sometimes only for a short distance going back to normal, but sometimes the coolant blows out through the expansion cap.
He said the system is bled so often by himself, that there's nearly only water inside. So an airlock can be left out. Coolant cap is changed more than once.
He doesn't beleave in a ECU Sensor failure or broken Thermostat. The circumstances of the case might underline his daubts.

No, his idea currently relates to an intermittant problem with one of the jiggle valves.
He saw once a lot of coolant flowing back to the expansion tank through the upper right small hose.
The idea is that a faulty jiggle valve might build a shortcut in the inner coolant circuit.

How about that ?
Any ideas, strategies to test anything ?

There are two of them. One in the engine bay top left and the other inside the head.

Looking forward to the speciallists thoughts.

Dieter K.

I guess this is a possibility Dieter. The jiggle valves are ball-valves are they not? I guess that either dirt or mineral build up could result in the valve being wedged open resulting in an unwanted bypass circuit establishing...
Rob Bell

No news from Torsten.

No more opinions ?

I'd love to get a jiggle thingy under my hacksaw ;)
Dieter K.

This thread was discussed between 19/03/2003 and 25/03/2003

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