coolant loss

[Pastry]

over about 5000 miles/a year my car has gone from max to min coolant in the tank. its such a slow leak i cant find any evidence of wetness round the hoses, radiator or engine; its not blowing steam once its warmed up. I guess it gould be anything but if anyones had a similar experience and can shed light on a potential source i'd appreciate it. cars on 75400 miles, on its original head gasket (one suspect) and its 2nd waterpump (replaced at 36k) - when it had its belts done at motortune peter didn't recommended replacing the pump when i asked if it needed it.

I had a rover that used coolant slowly and i kept topping it up; was fine for about 4 years /15k miles before it started using a lot more and eventually found out it was the HG (k-series cliche). I've read a few threads regarding replacing the HG as a scheduled maintenance so wonder if its worth getting it done, and if anyones had it done recently what sort of cost will i be looking at?

cheers

 

[Sandspider]

I believe that at least one 944 on here prefers to run at minimum coolant level, and will return to it if topped up then stay there. Once yours gets to minimum level, does it stop leaking, or will it lose more? Is it coming out of the relief valve of the expansion tank? (You can hang a bottle or something on the tube that comes out of the back of the expansion tank and collect anything that leaks out there).

If you start the engine from cold and look underneath you may have more luck seeing the leak before it evaporates from hot metal, but it doesn't sound like you're losing very much...

 

[Diver944]

ORIGINAL: Sandspider

I believe that at least one 944 on here prefers to run at minimum coolant level,

Mine's one of those and it's been like it ever since I've had it. No matter how many times I fill it to the Max it will eventually settle at the Min, and then stay there

 

[Neil Haughey]

My 968 did this but when I last checked it hadn't lost a drop from full. The difference was a new water pump as the old one I believe had a very slow leak.

 

[robwright]

+1 mine always setlles back at minimum. Have just bought a new header cap though. Maybe that will make a difference who knows. We will see after a good top up and a fresh bleed for good measure.

 

[Hairyarse]

I've had a similar problem with another car (non-Porsche) although the fluid loss was much more rapid, i.e. in a day or so but there was no sign of a leak anywhere! The only problem was the expansion tank cap. Cheap fix []

 

[Lowtimer]

I've just had a to have a new header tank under warranty on my almost-new (well... 58 plate) BMW diesel. It was losing around half a litre every 700 miles, which is about once a week for me in that car.
Seems a funny thing to have go on a car of that recent age. I have wondered if the acute cold in December made it a bit brittle and caused a little crack to open up through vibration.

In answer to your other point, if your 944 is on the original head gasket, and you do not want to regard the car as a disposable item, you would be well advised to change it. See Barry Hart's recent threat here for why.

 

[Pastry]

took it into motortune for its MOT and asked if theyd take a look, so they pressure tested the coolant for 1/2 hr and found a very small leak in one of the rad hoses, and tightened it up. i'll keep an eye on it. cheers for the replies.

oh it passed its MOT too

 

[zcacogp]

Another one that settles just below the Min level here.

It worried me at first. Then I realised, as Giles said, the level drops to a point and then stops dropping, and I stopped worrying.


Oli.