Club 80-90 Forums

Hi all, just wondered if anyone could help with a little mystery I have?

For over 12 months now I have had recurrent problems with loss of fluid and overheating for various reasons, all resulting in my trusty red warning light alerting me to the problems.
First - head gasket went - head gasket replaced = red warning light gone
Second - Thermostat broken resulting in header tank crack (on our way back from Vanfest!) - both replaced = red warning light gone.
Third - on our way back from Cornwall last Friday night (and now persitently since) - when the van gets running, after a few miles the red warning light comes on (turned the engine off and on again and the light went out). There are no leaks, coolant is getting through to the radiator (as it is warm to the touch) and the cooling fan is working. What could it possibly be this time? I've just been out and noticed that the header tank was very low and the expansion tank was full, but I can't see where else the water could be going...?

Any help or advice greatly appreciated. Cheers, Mark

Engine type may help. Also just to check your terminology Header tank is the pressurised tank with the dalek cap and expansion tank is what your calling the top up tank available through the engine hatch, yes?

if header tank is empty but expansion is full there is an oportunity for air to enter the system rather than header tank sucking replacement fluid from top up tank when the engine is cooling down. the Dalek cap on the header tank may be worth changing for a good one from Brickwerks. You may have a crack in the header tank that only leaks when hot, they can fracture around the neck esp if overtightened when hot. Leaks can appear elsewhere and drip onto exhaust or engine block and evaporate before you see it. look for pink/white crystals. Also prongs in header tank can need a clean giving false error on low coolant. It can fail in a way that gives the error you are getting too, take the connector off the top and jump the pins on the wire together this should 'say' the header tank is full, if you still get same symptoms there is a wiring issue.

Just re reading your post If the header tank is Low then your red warning light should come on as the level sensor is operating correctly and sensing low fluid.

Thanks Hacksawbob - I think you may have just given me the solution! The new header tank I have on is only a few months old, but I had noticed that the Dalek cap was becoming loose. I thought I had resolved that by putting some plumbers joint-sealing tape around the thread prior to screwing the cap on, so this is most likely to be where the air is being sucked in. I actulally have a new replacement header tank and Dalek cap from Brickwerks ready to go on (the header tank and cap I have on was from JK and seems to be a bit inferior). So I reckon that should do it! Fingers crossed and many thanks for your thoughts! Mark