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MG MGF Technical - coolant drop

Any Ideas where my coolant is going.

Drops about 1/2 inch every 50 miles or so (2 cold starts)

no visable leaks (esp all round HG)

no water in oil

no oil in water

no carbon monoxide in water

Have replaced the pressure cap just in case

had the system presurised (using compressor engine off) to > working pressure for ages and still no sign water anywhere (and no drop)

Me and local garage (reputable) stuck with this one

I have had HGF in past and am obviously concerned about this, However had it all fixed properly including all recomended "upgrades" and a competition motobuild head gasket put on at same time.
nigel

Weeping water pump? A small weep would not give any visible signs externally. The small amount of coolant would evapourate off before becoming a visible leak.
Dave Livingstone

Rad ?
S Laithwaite

I had the symptoms that you describe, dropping of coolant from max to min level in tank every 30miles. It turned out to be a hole in the radiator, caused by a stone. Also noted that the radiator was slightly corroded. Replaced the radiator it and it cured the problem.
Jo

What year Nigel? If an early F it could be the inlet manifoLd gasket.

Jim
Jim Hosking

Jim, you took the words right out of my mouth! Early 1.8MPis are particularly prone to inlet manifold gasket problems: the gasket material deteriorates over time and cracks. Water loss isn't always visible either (can bleed water into the engine inlet tract)...

Water pump is also another definite possibility, as Dave suggests.

I guess that this will boil down to careful inspection of all the rubber hoses, the underbody coolant pipes and the rad to exclude all possibilities.

With the thermostat closed on a cold engine, would that not only test the engine and coolant bypass system?
Rob Bell

Oh dear Rob - "I guess that this will *boil* down to......." I trust you've got your coat? :o)
Mike Hall

Have a look at the rad!

you might be looking at the wrong end of the car!

Neil

Mike, I've left the building... ;o)
Rob Bell

the car has definatley developed a "sweet" smell from engine bay but still no obvious signs where it is comming from, guess it will be obvious eventually

so how much damage can you do running the car with low coolant levels.............................
nigel

If you want to inspect the water pump it is quite simple to remove the cambelt cover, then you'll be able to run the engine and keep an eye any leaks coming from the pump..... Having a look at the workshop manual the pump doesn't look too difficult to change provided your comfortable with mucking about with the cam belt....

Tim
Tim

>> so how much damage can you do running the car with low coolant levels............................. <<

You don't really want to find out. :o(
Rob Bell

Nigel,
You say the coolant drops 1/2 inch every 50 miles or so !Do you then top it up and it drops again or if you leave it for another 50 miles will it drop 1 inch ?or will it stay the same? sometimes coolant has to find its own level and then for no apparent reason stays there, worth checking this out, the other suggestion" and this is from practical experience "when pressure testing a cold system no leak may be apparent but when hot, a different result !
Robert
R J Hemphill

gona have a look at the water pump, Havn,t got access to a manuel but competant mechanically (fully rebuilt a 1964 B)anybody give me a few hints on how to get at it
Nigel

I dare say you already know how to get into the engine bay, but there's an article in the MGF/TF FAQ if you do need to know...

http://homepage.ntlworld.com/dotcomoff/


Other suspect areas of the colling system for leaks, particluarly on older F's...

Coolant pipes run from front to rear - suffer from corrosion.

Radiator - as coolant pipes.

Expansion tank cap, although I'm not sure how much coolant you could expect to lose through here if it's faulty.

Rubber hoses in the cooling system - also reported here recently ISTR as failing with age.

HTH. :)
Paul Lathwell

Roberts observation is similar to mine. If I fill my tank to the standard filling marker at the tank seam it will eject about 1/2 inch of coolant and settle at about the lower mark without losing any more. I spent weeks topping it up and looking for leaks. A good test to satisfy yourself whether it is a leak or not is to pressure test the system. Needs to be done both hot and cold and can also be done on the cap to check whether it is working properly (I went through 3 before I got one to work)
Phil Stafford

My 97 1.8i does exactly the same.

The coolant level drops by 1/2 an inch or so after my journey to work (120 miles Sun night) but I always top it back up before the next journey (another 120 miles Fri night). Maybe I should see if the level drops further if I continue to use it without topping it up. It may be that it will demonstrate the same odd characteristics as Phil's car.

I also have no visible leaks. I recently fitted a new radiator and I changed the main coolant hose to the cylinder head 3 months ago. I park it in a garage over the weekend and have noticed no drips of coolant under it anywhere.

I'm in favour of the suggestion that the water pump may be weeping when the engine is hot and hence the coolant will evapourate making it more difficult to spot. I guess it should leave some white marks on the engine even if it is just weeping. I will take a look next weekend.

One thing I have not checked is my expansion tank cap. Presumably the faulty caps don't allow the system to run at the correct pressure and therefore allow the coolant to slowly steam away?

R Longmore

>>> the coolant will evapourate making it more difficult to spot. <<<
Start sniffing, as the evaporating coolant has a typical smell (even in small amounts).

Have a look at the plastic bleeding screw on top of the radiator as well.
Erik

Just a thought, but anyone having this problem checked inside the car ?, what about a leaking heater unit or connections ? wet carpets ?
Mike
Mike (@home)

Hi there,I am a new member to this bbs site so any help advice or tips would be welcomed by me.
I have owned a 99 MGF for 1 year and I anjoy driving it very much (she is my babby
I have a 99 MGF and have also had a recent head gasket replacement and am also very worried about my coolant loss in the past few weeks. I noticed i was loosing approx 1 litre per weekand i just keep topping it up until today when i took it to my mechanic.
I just recieved my car back from my mechanic and he told me that both coolant pipes that run underneath the car need to be replaced as they are nearly rusted out and are leaking coolant. Is this a common problem?? Can replicas be manufactured in stainless steel or is there an aftermarket place that manufacturs some more suitable replacements.
Any help or direction would be appreciated.

Thanks in Advance

Jazz1
P. Russell

This thread was discussed between 18/03/2004 and 22/03/2004

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