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MG MGF Technical - Have I caught the HGF????

I have just had to have my partners' MGF recovered by the RAC. They confirmed there was a water leak by pressurising the expansion bottle and watching the water fall from the bottom of the engine. He was unable to diagnose any further as we were unable to get to the engine whilst at the roadside.
The symptoms were as follows...

1. Steam coming from the side engine vents (she didn't say which side).
2. Water dripping from the bottom of the engine... yellow in colour. (The same colour as the coolant.)
3. Temperature gauge remains normall, no signs of overheating.
4. The coolant bottle is still and 3/4 full and oil free.
5. Seamingly no loss of oil.

The only other things of interest are that the car had the 48,000 mile service a little over 5 weeks ago and cambelt changed a week later. All this work was carried by The Bristol MG Workshop mainly due to the know issues with the F.

Could anyone give any clue as to what this could mean. Is this is very early sign of HGF or could it be something else like a water pump/pipe leaking. The car is going back to the garage on Monday by tow but I'd like some ideas that I could put to them.

Heres hoping I avoid a new head!

Thanks in advance.

Simon Cummings

Sounds like the front/rear pipes under the car - they are known to suffer corrosion. Or a hose clamp somewhere - likewise, the OEM articles are not great. The coolant level being OK and oil free is an optimstic sign.

Good luck - of course it's impossible to promise on the diagnosis, it just seems likely to be good news to me. HGF is usually a little more spectacular I believe.

Ed Clarke


Your diagnosis sounds great to me... no least because it sounds a lot less expensive than an HGF!

When you say front/rear pipes what do you mean? I'm a layman when it comes to mechanics, so should I let the garage deal with it or is this a very simple thing to check myself?

Also, more opinions would be more than welcome.

Thanks again

Simon Cummings

Simon, there are two steel pipes running under the car which take the coolant from the engine to the radiator and back. These can corrode, or in some cases, the rubber hoses themselves can perish. Best inspected with the car raised on a ramp.

Another potential cause (if you have a 1.8 MPi) is a failure of the inlet manifold gasket. I've just had to have this replaced on our Rover 214 because of water loss (but this was gradual)- and I HOPE this is all that is wrong with my MGF that boiled off its coolant last week... GULP

For those who are interested, Yimmy and I were just setting off to Cornwall on Honeymoon when we both heard a very odd noise from behind. It sounded either like something rubbing against the body work or like the sound you get when driving through a deep puddle and water is sprayed against the body work. As there was no standing water, I thought that something was fouling the rear wheel arch, stopped the car and hopped out to inspect the rear tyre... nothing wrong there, but spotted whisps of steam from the bootlid vent and from the boot shut lines.
Opened the boot- no water in the expansion tank, some coolant sprayed around in its vicinity. Tank remained pressurised as I discovered when opening the lid. Unfortunately a wet day, so I can't be confident that there wasn't water dropping from the engine. BUT no "mayo" in the coolant or oil. Topped up the expansion tank and limped the MG back home. Should be investigated by a trusted local west country mechanic today; hopefully NOT a HGF.

I suspect that the inlet manifold is the culprit- and will arrange for it to be replaced (it's still the original fragile black item). But the odd water-jet noise is a worry. Anyone else experienced this? I didn't get the chance to remove the engine inspection plate to look for evidence of HGF, but keeping my fingers crossed. Like you Simon, no problems with either water or oil temperature.

Rob Bell


Again many thanks. I've had chance to look briefly under the car and the front/rear pipes do look a little suspect (extremely rusty to be precise). Fortunately, the car is being towed to the garage tomorrow morning. If they confirm that it's not the HG then I will ordered the replacement pipes from Mike Satur (unless anyone can suggest anything better).

The car is the VVC so could the inlet manifold gasket still be the cause?

Anyway.. we will found out more tomorrow!

Simon Cummings


dunno whether MS has the uprated non corroding replacement pipes already done. So a local dealer or B&G is another option for the standard part.

The VVC is said to have the new green gasket installed since 1998 as well. But I've never heard of any fault here at the BBS. The VVC manifold is made from aluminum and hasn't got the plastic material 'creap' behavior.
Leave it out.

PS. Rob, CU on Saturday ?
Dieter Koennecke

Hopefully yes Dieter- but it may depend a little on what ferry crossing times we get. I'll keep you posted :o)
Rob Bell

mini F meet in Germany this w/e? <trying to get out of going shopping>

Kind of- although perhaps more of an MG-Rover mini meet! ;o)

Yimmy and I are driving Yimmy's younger sister to Trier this comming weekend- so the MG is out (even assuming that all is well), so we are taking Yimmy's R214. Which is an ideal hold all for picking up Nikolaj's unused Bridgestone tyres!

Not sure about ferry crossing times yet, but hope to meet up with Dieter and Nikolaj sometime Saturday before heading back to blighty.

If you or anyone else happens to be in the area Gareth - maybe see you there! :o)


PS Must persuade Yimmy to change the Rover for a Z car... ;o)
Rob Bell

just got the release due Saturdays shopping from the wife ;)
Me will be there.
Details at last as well by mobile contact.

Dieter Koennecke

Dieter / Rob.

The bad news, according to the garage, is that it is the HG - or at least, they believe so.

The next step to confirm the problem is to take the thing off and start work...

Therefore should I take this opportunity to have a non-standard or improved HG fitted (again such as the MS competition HG) or can someone reassure me that fitting a standard Rover part will suffice?

Also, is it worth getting any other bits fitted to aide cooling (K&N ??) or reduce the chances of this happening again.

Look forward to your thoughts

Simon Cummings

Err, sorry about it.

>reduce the chances of this happening again.

No recommendation on any add on parts.
Just see that the repair gets done iinside the specs.
- head condition (plain surface)
- oil in the system ? should be flushed very good.
- check the cooling fan sensor contacts and clean and grease them (brown connector LH rear)
- replace the airintake manifold sealing with the green coloured part if not already done.
- replace the coolant expansion tank cap and get a spare of this crap thing to your tool set in the bonnet for later use.

How much miles had the engine ?
May be some of the speciallists here have some different ideas.

And at last, don't forget to enter the gallery at

Dieter Koennecke

Hi Simon,

Make sure they use the updated gasket GUG702613HG and replace the plastic cylinder head dowels with steel ones LUY000010.There is lots of good info in the archive on this especially information from Roger Parker on part numbers and DIY replacement.

Paul Robertson

This thread was discussed between 29/09/2001 and 03/10/2001

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.