Coolant Loss

[fastandcurious]

I am having to top up my expansion tank every hundred miles or so. I've no idea where its going. There are no puddles or visible leaks and the car doesn't suffer any running problems. No over heating or boiling over or any of the usual Head Gasket symptoms. The level in the expansion tank used to sit around 2 inches from the bottom but now after a drive it's usually empty and needs a quarter of a litre or so to top it up.
I am aware that it could be one of a number of things, but if anyone knows of a common weakness that reoccures on a 500 serp, help much appreciated.

[yellowgriff]

Check inside car around both foot well, if wet inside it will be the heater matrix,,
get the car hot up to working temp & check for steam around outside edge of rad..
check hoses for damp patches or gunk/....
Have you got gung in side oil filler cap.. If all else fails go to a good mec & get it presure tested..
Good luck GOLDIE

[Ballistic Banana]

Could be a pipe maybe split/jubilee clip loose somewhere. Its alwasy hard to find when hot as it evaporates when hot, when cold theres not enough pressure to seep out..

Steve Heath does an excellent product that you screw into the top of the Expansion tank that lest you put a bicycle pump to build up the pressure while cold and i have found a number of jubilee clips that seem tight but arent and water is seeping out under them. So worth either checking them all first or getting one of Steves gizmos..what would we do without him

BB

[daveb500]

I've just had to replace the blue pressure cap (VW Golf Mk2) on the expansion tank on mine. It's cheap and easy to change so might be a good place to start.

[Colin RedGriff]

I had a similar problem and then eventually the water temp started to become very erratic. I changed the rad as I had access to a new one at a knock down price and it fixed the problem, stable temperature and no coolant loss.

I can only guess that there was a pinhole in the rad somewhere. I never had any puddles under the car so I think the water must have been evaporating off the rad before it could drip.

[crackedfinger]

Steve Heath sells a pressuring adaptor that help find these leaks (not had the need to try one myself)

[spend]

You know those 2 little hoses that used to goto the throttle heater and sit near the rocker cover with bolts bunging them up. Seems just as easy to connect your air line to them IMHO or even to the Swirl tank expansion pipe for you serpy people?

Not heard of a leaky water pump for a while, maybe folks don't bother to post about it these days?

[AntonyJ]

Not heard of a leaky water pump for a while, maybe folks don't bother to post about it these days?
[/quote]


Mine leaked last week.












'till I tightened it up........

[fastandcurious]

Thanks for the ideas Guys. Come to think of it, the pressure does seem a bit weak. The cap doesn't hiss when I undo it, when the engine is still warm.