Coolant leaking all over the garage floor

Anyone have any idea what is going on with my car? I have been losing coolant over the past week or two, usually when I have parked the car up overnight in the garage.when I drive my mgf their is no coolant loss, but when I stop the car it appears to empty itself of the coolant expansion bottle.

I have bled the system, bought a replacement cap for the expansion tank and lifted the expansion tank out and checked for hose leaks.

The coolant seems to accumulate on the drivers side rear, and drips down from the chassis rail....could it be a leaky coolant header rail?

I don’t think it’s the head gasket, because I fitted an updated one when I re-built the engine 3 years ago.

Any thoughts gratefully appreciated!

I've had something similar it was the water pump.

My money is on the water pump too

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Any idea how much it is to replace a water pump, presumably the cam belt and tensioner at the same time?

Lost the last engine due to a tensioner failing, whilst the pump is being repaired, may as well get the lot done!

Contact Rough Luck Racing mobile mechanics, they cover uk wide, at a guess your looking at £250, can't reccomend them enough, give Jon a bell and he will talk you through it.

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Cheers Steve....really appreciate your help.

Ericmgf wrote: Anyone have any idea what is going on with my car? I have been losing coolant over the past week or two, usually when I have parked the car up overnight in the garage.when I drive my mgf their is no coolant loss, but when I stop the car it appears to empty itself of the coolant expansion bottle.

I have bled the system, bought a replacement cap for the expansion tank and lifted the expansion tank out and checked for hose leaks.

The coolant seems to accumulate on the drivers side rear, and drips down from the chassis rail....could it be a leaky coolant header rail?

I don’t think it’s the head gasket, because I fitted an updated one when I re-built the engine 3 years ago.

Any thoughts gratefully appreciated!

I had almost exactly the symptoms you are describing last year. I drove the car about 30 miles - no problem. Parked up and a while later noticed a large puddle under the car.


I topped up, ran the car to duplicate the problem with the engine running for half an hour. Nothing. Then about 10 minutes later coolant started dripping down from the hole towards the rear of the chassis member that runs to the left of the coolant pipes.


Investigation revealed that there was wetness inside the tunnel at the back of the car. Pulling out the box between the seats enabled me to stick an arm in and feel wetness at the back, under the petrol tank, near where the heater pipes pass out into the engine bay.

With advice, it was decided the problem was excess pressure. I replaced the pressure release thermostat (PRT), which is straightforward.

Since then, I have had no further problem.

I would add that I had the cambelt, tensioner and pump replaced about a year previously, so never even considered the water pump.

Good that its solved. And good to keep.in mind! Thanks for sharing.

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Finally got the problem resolved...perished water pump gasket!...got the pump replaced and cam belt also for £270 by the brilliant team at Rovetech in Stockton on Tees....many thanks guys!