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MG MGF Technical - need advice: coolant leak.

I have a coolant leak, the only problem is it's very slow.
About 2 cm out of the expansion tank a week, but is very constant.

The problem is, there are no obvious signs of leaks.

Anyone got a quick check-list of common failure points, that i could examine more closely?

Thanks for any advice.

paul weatherill

Personal experience.....
Large dimeter hose where it leaves the front left engine (see Dieters website for info...section on hose clips) often diagnosed by drips of coolant on the underbody pipes which are another possibility for a slow leak.
Dare I say it...check the archive search under slow coolant loss.
Charles Dundas

Check your dip stick for mayo.....

<<Check your dip stick for mayo....>>

Shh, don't say that.

Then again, if I've only had my car back a few weeks after Rover have "fixed" it, I should be able to claim it was their fault.
paul weatherill

>>I have a coolant leak, the only problem is it's very slow.
About 2 cm out of the expansion tank a week, but is very constant.

I've had this before on our Rover 214. Inlet manifold gasket had failed. If your car is a 1.8 MPi, then this is very likely to be the case with you too.

Check also the condition of the coolant resevoir cap; if inadequate pressure, coolant will slowly boil off.

One other possibility that occurred on my MGF (6 years old): corroded radiator caused the water leak. Check too the condition of the pipes under the car as these rust with age (high level of suspicion on 5-6 +year old cars).

Hope this helps

(see also
Rob Bell

Thanks Rob,

The Car is a P-reg VVC, so I expect something has coroded away to dust.

The coolant pipes looked ok, slightly stone chipped, but no sign of leaks.

I will check the coolant cap, as it does seem to lose more on long trips.

[seem to get a <page not found> when trying to link to your water leaks page from your main site.]

Thanks again.


paul weatherill

My F had a very, very small weep from the large (to/from radiator) underbody pipes, at their connection to the flexible hoses - rear end.

The leak was only when the system was pressurised (and so hot), and was so slow that the heat of the pipes themselves caused the leaked fluid to be evapourated away before it could drip onto my (painted & sealed) garage floor.

Cured by adding jubilee clips in front of the rubbish standard sprung hose clips.
I only found it when the car was up on a hoist to have 4 wheel tracking done. I nipped out whilst the car was being worked and bought the jubilee's, and fitted them before the tracking was finished.

You will need to check these pipe joints with the engine/coolant up to temp.

Paul Lane

The water leaks page is work in progress - hence the '404' error.

On balance, I still wonder about the inlet manifold gasket, although the items found on VVC cars have a superior reputation. If the rad is suspect, this will take some dismantling to inspect; it's neigh on impossible to properly inspect with the bumper etc in place...
Rob Bell

<<Cured by adding jubilee clips in front of the rubbish standard sprung hose clips.>>

Worth getting Mike Satur's full set then? just in case.

I plan to have the bumper off shortly, for Andy (Scarlet Fever) headlight Mod, so will have a close look then.

Unfortuately one of the screws holding the bumper on is completely rusted in.

Hmm, wondering if its worth throwing some money at a dealer, for them only to come back and say they couldn't find the leak.

paul weatherill

Few a few quid at a friendly garage it's definitely worth while getting a pressure test done. If there is a leak it'll certainly show up. Then you can decide whether or not the job is DIY or 'other'!

I had this done just after Christmas and ended up with a new manifold gasket and a whole heap of new clips, there were leaks every where. My car is an early 1996.....


Thanks tim,

I want to get that done, thought they would just do a visual check and charge me for a couple of hours.

Pressure check sounds a much better idea.

Thanks again


paul weatherill

Hi Paul

Had this recently myself, whilst the coolant was leaking slowly I had the added benefit of being able to 'smell' the coolant at the rear of the car. This all turned out to be my Inlet Manifold gasket. I let this go on for some time, topping up wasn't a real problem, doing this you are putting your catalytic converter at risk, as happened to me! So it needs sorting ASAP. Cost of replacing gasket, 144, cost of Cat 126+VAT plus gaskets and then 15 for it to be fitted, because, as we are warned often enough, the Cat nuts are a real pig to get off, I had to have mine burnt off......hope that helped.



The Mike Satur clips are a really worthwile investment. I used regular jubilee's as it was a dash out job.

I have since replaced virtually all of the standard fitted spring clips with jubilees at the "engine" end of my car. Standard jubilee clips are ok, but Mike's are better as they apply even clamping pressure without the risk of "biting" into any hose material.

Paul Lane


Check also the heater hose pipes behind the right hand footwell light panel. Water can drip from them into the carpet and will not be detected unless you lift the carpet and felt. Been there, read the book and seen the movie! T shirt next week. :)

Bruce Caldwell

This thread was discussed on 02/04/2002

MG MGF Technical index

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