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MG MGF Technical - To drill or not to drill

I live in constant fear of HGF and that is really not a good life!. My F is a early ´97 mpi completely original with only 30.000 km on the clock. A truly weekend car. Every time I drive check the water level before start, and after do not exceed 3000 before temp reaches 90°. I have been told that an easy way to prevent HGF is drilling holes in the thermostat. Would you people recommend doing that?
Many thanks in advance. Jaime.
Jaime Baren

Drilling the thermostat reduces the chance of HGF, but doesn't eliminate it. The downsides to drilling hole(s) in the thermostat are longer warm up period, with increased emissions and fuel consumption whilst the engine remains cool. The extent of this problem is proportional to the size and the number of holes you plan to drill.

IMO you're already treating the car with respect by not thrashing it until the oil temperature reaches 60degrees. This is what I've always done - and so far, after 80+k miles and nearly 9 years, no HGF.

Dieter's website has more details on drilling the thermostat - I'd probably not drill more than one hole, at a diameter of not more than 4mm.
Rob Bell

Also to drill the thermostat you will need to at least partially drain the system. It would apear that the risk of HGF is greatly increased after a system drain - if all the air is not bled out of the system.
Steve Ratledge

Hey! Dont get paranoid, but a little paranoia can go a long way. I think you are doing all the right things just keep an eye on the fluids and run the engine normally.

drilling a hole in the thermostat is a bit of a bodge job.
Neil

Drill the thing, better still take it out all together if you don't mind being frozen stiff in the winter. Did the original F's not come without a thermostat ?

Even better put a Honda engine in it !
HGF victim

Hi Ian. I thought we had agreed not to discuss the company Vectra until Vauxhall replaced the engine. Signing in annonymously didn't fool me one bit!!!
JohnP

>> Did the original F's not come without a thermostat ? <<

Errrmmm... All engines use a thermostat!
Rob Bell

>>>>Errrmmm... All engines use a thermostat

What about a 2 stroke then !

But seriously I seem to recall somebody saying the early F's did not have one fitted. After all the engine will still run but may take a significant amount of time to warm up. Who cares about emmisions ?
Me again

Okay - nor do aircooled Beetles or Porsches! LOL

But no, no MGF has ever been supplied sans thermostat.
Rob Bell

Okay I conceed they didn't come without a thermostat fitted.

Me

>My F is a early ´97 mpi

Immidiately check the underbonnet fusebox,

Change both 15Amp(green) to 20Amp (yellow).
There are only two green coloured.
The _wing side_ one is the front fan fuse. The other is the aircon front fan fuse.

IMO, on the other hand ... *never change a running system*.

> I'd probably not drill more than one hole, at a diameter of not more than 4mm.

That's right. But you can just buy a new design thermostat with jiggle valve included.

BTW, I decided to remove most contend of the thermostat drill webside. It was a point of great discussions from years ago, but lost importance due to improved know how in the last three years.
(TF design and Lotus Elise design coolant system i.e.)

Regards
Dieter
Dieter K.

Dieter
Being new to the F are you saying that changing the fuses 15a to 20a does actually help to avoid HGF ?

Thanks Paul
Paul Carugati

Paul.
>> Changing the fuses 15a to 20a does actually help to avoid HGF ?<<.

It wont stop HGF, but may help your F to NOT overheat which will cause Er....... Hmmm........

The front Radiator Fan Hardly ever comes on, so the sudden surge of power when it is needed can blow fuse, so no fan, so overheat so, ........

Check Dieters site , he will explain a lot better than me !.
Mark.L

>actually help help to avoid HGF ?

Of course not actually, but in case of a temporary sticky front fan and idle engine due to i.e. a traffic jam after a hot ride.
Had this myself at my 1999 MGF in last spring.

It's a known fact, that the fuses got changed to 20Amps official in 2000 to the aircon fuse and to 20Amps at the front fan fuse with mgtf introduction .

I sold a couple of on a funny ebay auction. (Including website donation)
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&rd=1&item=7920857354
... two of the lucky 'winners' had found the front fan fuse already gone when they swapped in the parts from my kit :)
Another one found a sprig blocking the fan ....

Cheers
Dieter

Dieter K.

Thanks Mark - Thanks Dieter --- Thats the mornings little job !
Paul Carugati

Oops, written parallel .. Mark, nothing on the site. Would be bad for the _big business_ ;)

However, the offer is 5 Euro for a kit, i.e. cash in a letter. (Woun't worry if anyone ships 5 quid instead .. LOL)

You get:
Thanks for the *donation* :) and regards from Germany, the English instructions 'colour print'(well, kind of english), an inlett for the owners manual, couple of stickers, the two yellow items and free postage within Europe and the UK.

Bargain, ehhhy !! ;)

Place your order with header *Fan-Kit 4me* to dkoen at web dot de.
:)

Cheers
Dieter
Dieter K.

Drilling sounds interesting however I wonder whether it would possible to replace the actual thermostat installing another which may perhaps open at a lower temp. That would perhaps be more scientific method other than drilling a hole?
On the other hand for those that suggest using the newer thermostat technology, I understand that is almost impossible to get one of those new devices.
John Wilson

Hi,

<.. What about a 2 stroke then! ..>

Water-cooled two-stroke? Noisy, smelly, dirty, inefficient and uncivil it may be, but it needs and uses a thermostat just as much as a four-stroke.

Yes, the (intact) fan fuse on my '98 F is 15 amp. On my 214 it is 20A, and occasionally fails. A couple of years ago I was stuck in the traffic in Arles, an unlovely place, in blistering sun when the fan fuse went, and up soared the temp into the red. I had the heater on full blast to hold the temperature, with all windows open. When I came to change the fuse I read the diagram upside-down, and pulled out the central locking fuse (well, they were both in a corner and both the same rating). I replaced the fuses but the central locking and the immobiliser wouldn't work! I entered the key code and to my immense relief the engine was mobilised. Then I tried the spare remote blipper, and that worked. A few days later the original blipper came back into life. Funny thing, these electrics. Just make sure you take all your key codes and spare blippers when you travel! Not pulling the wrong fuse also helps.

Oh yes, a lower rated thermostat will not stop the thermal shock produced by abrupt opening/closing, whereas the drilling alleviates this a little. But if it's running OK then don't mess with it!

Regards, Kes.
Kes

revised the Thermostat site.

http://www.mgfcar.de/thermostat/

The direct link to Robs coolant system options missing, though. Didn't find it :(
Dieter K.

Is this what you're looking for Dieter?

When the old site went down, I completely overhauled the site's structure - it needed it - some it dated back to the original website of 1999! 8-O
Rob Bell

D'oh - forgot to write the link: http://www.mgf.ultimatemg.com/group2/common_problems/hgf_pages/cooling_system_modifications.htm
Rob Bell

I expect that page to be updated by the weekend ;-)

I worked out the compolent cost, it came to £4.50, not including board, solder, wires and box.
Unfortunatly most of the compolents have to be ordered in much bigger numbers (capacators used 2 of 5p, min order 50) and the postage cost is £5 from RS
Will Munns

Broken link at the top of the page should point to http://www.mgf.ultimatemg.com/group2/common_problems/hgf_pages/HGF.htm

:o)

New page looks superb, nice one Dieter.

BTW - worth including a link to Carlo's excellent website dealing with HGF and thermostat design issues in the Lotus Elise? http://web.tiscali.it/elise_s1/
Rob Bell

>> I expect that page to be updated by the weekend ;-) <<

Great news, thanks Will! :o) I wonder how on earth we ended up with a quote of 100 quid per unit??? 8-O
Rob Bell

>I wonder how on earth we ended up with a quote of 100 quid per unit

That depends on what design criteria you gave them!

I have played fast and loose with the specs, but I know what type of problem you have to solve and where I can trim.
Will Munns

The guy who quoted disappeared off on the Paris-Dakar rally shortly after with the Nissan team - so probably the kit he designed was designed to withstand being run over by a Landrover! LOL
Rob Bell

http://web.tiscali.it/elise_s1/
Great, Carlos enhenced the document. I thought it was temporary only.

@Will
>I worked out the compolent cost, it came to £4.50 + + + +

??? dooh, didn't you know, 'me' is electronic components buyer !!;)

I think we need to take contakt ASAP.
Do you have Gerber files ? component list ?

Regards
Dieter


Dieter K.

Gerber??

The list is quite small
2 x 22uF
6 x 1M ohm
1 x 2k2 ohm
2 x p-channel fet with on resistnace less than 0.06 and capability of over 3 amps (I used one for 30+ amps)
1 x comparator
1 x log pot

Box? (matchbox size)
Board? (we should spin some if there are going to be many more)

Nothing clever about the circuit
Will Munns

Will, the matchbox arrived yesterday morning, thanks! Will get on to TS to install a pump in my car, along with this pump timer :o)
Rob Bell

This thread was discussed between 02/11/2004 and 05/11/2004

MG MGF Technical index

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