E30 Zone

header/expansion tank pressure relief cap actually. Anyone had one of these break?

Mine seems to have a broken black plastic ring around the inside of the cap - not sure how ive done it but it doesnt seem to seal very well anymore and the coolant system starts to loose pressure when the engine gets up to operating temp. Got it back under control by easing off the gas and putting the heater on - which was nice in the hot weather

Only noticed it when I saw the level in the header tank go right up, then drop back down to low once the engine cooled. This morning it was loosing coolant all the time. Car has never run hot and recently had a good coolant flush so Im wondering if i broke the cap when getting it on/off.

Im picking up a new one this afternoon - but has anyone else seen this before?

Have a look at the bottom of the cap, there are 2 versions. If it has a black insert then it is an old superceded cap but if it is yellow then it's the updated version.

Apparently the old black ones were prone to problems and the dealers were suppsed to change them FOC for the newer yellow one, but I've come across several of the old type and they don't sem to seal very well.

Cheers,

Iain T

If it's a black one, take your VIN with you, and as long as it shows on the database as have not being changed already, the dealer should give you a free one.