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MG MGF Technical - Losing coolant, any ideas?

My MGF is losing coolant. I can't see any leaks from anywhere. The temperature sometimes reads zero, but never goes above halfway. There is no gunge on the dipstick, no steam from the exhaust, no water in the foot wells. The radiator is new, the thermostat is also new & the fans always kicks in but the header tanks level has dropped from full to less than half way over the past several weeks. What's going on, any ideas?

Thanks in advance.
Mark kimberly

Well Mark, as you say, everything is new, maybe there was some air in the coolant circuit after installing the new parts. Fill up the coolant and see if it happens again.
BV Bruno

Loosing coolant and no leaks? What is the car performing like, is it down on power?

Could be inlet manifold gasket (is the car an early one? is it a VVC?) Coolant could be getting past the gasket and being sucked into pot 1.

Just an idea.

SF
Scarlet Fever

leaks in the pipes between the engine and radiator perhaps? But the header tank is supposed to be only half full. If you have filled it to the top, the excess has probably been ejected through the tank cap (as it is designed to do?). If it drops much below half way, then start to worry.
Neil Courtney

>>but the header tanks level has dropped from full to less than half way over the past several weeks<<
What do you mean by 'full' ?
As Neil says, the header tank should not be full - it should be filled to the seam - about half full; there is a stepped level indicator in the tank, visible with the cap off, that shows max and min levels.
The radiator cap itself could also be losing coolant - is there any sign of coolant on top of the header tank ?
Steve

I once had a slow loss of coolant (3-4mm level per day). It was the water-pump leaking. Check for dryed yellow marks on the lower part of the engine-block. I've got a picture I could E-mail to you how it looked like.
Beat Fischer

Try changing the cap..... this is notorious. for 3 quid it's a worth while investment. A correct spec cap should vent at 15psi a dodgy one ....who knows how low that might vent.
tim woolcott

As Tim says, check the cap first. This is really a common fault, and better still, is dirt cheap to replace :o)
Rob Bell

>s dropped from full to less than half way over the past several weeks

As steve says, some owners find that the level drops down to just over the bottom step, fill it further and it drops to there, leave it and it says there.
Will Munns

I have always found that my coolant level is happiest just above the minimum mark above that and it used to come out the cap. One other thought oon dropping coolant levels, could it be the heater matrix.....? Check under the footwell carpets to see if there is any dampness there.
Will, Am I right in saying the carpets might get damp if the matrix is leaking or am I getting confused?
tim woolcott

I had this for a couple of months. Persistent coolant loss, with no damp patches on the garage floor. It turned out to be a radiator leak when this finally let go in Sainsbury's car park - green puddle under front bumper. I was quite relieved - I was beginning to fear the dreaded HGF. AB
Adrian Bennett

Coolant on mine has been dropping slowly too. The Techspeed guys identified it as a weep from the radiator, which I still need to get sorted, but the amount was so minimal it was dropping onto the inside of the front bumper and as such never showed itself until you were underneath the car and knew where to look.
R Baker

I finally traced it to a tiny spilt in the hose to the radiator
Thanks for all your help guys
Mark Kimberly

Thanks for updating us with the outcome Mark. Which hose was it? Any pics for Rob Bell etc. ?

Dave

This thread was discussed between 11/06/2003 and 16/06/2003

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