Nexuas

Luckily yesterday on the way to powerstation I ran out of windscreen washer and so had to pull over at a service station, lifted the bonnet to fill up with water and screen wash, to find steam coming from the engine coolent header tank. I topped that up with about a litre of water and procceded to cheltenham with a little less vigour.

When I got there I checked the water level and it was just above Max, which is where I filled it to at the service place. Towards the end of the day the mechanic noticed there was collent dried onto the front cat pipe, we had a seach for the leak and determined it was coming from the front passenger side of the engine bay around the header tank.

He checked the water pump and he seamed to think that was ok? We idled the car for ages to get it up to temperature and reved it, but could not see where the water was coming from?

Any ideas?

Drove home and checked the water level and it was just below max (Engine hot 80 miles of motorway driving), but there did appear to be alot of water on the undertray? Checked it just now with the engine cold and it is just above Min? There is not much of a gap between max and min. Equates to about a mug full of water?

Could this just be heat expansion causing coolant to come out of the overflow?

scoobyslut

It sounds that way to me, as if too much water in the system, it expands into the expansion tank, so when this is full, then it drops down onto the exhaust. To be sure, I'd simply keep an eye on the level and check daily for a few days, then go back to your weekly check routine.

prana

your coolant system does not come on all the time, only when your thermostat reaches a certain temp. when it does, it gets pumped through the engine jacket, radiator etc. and will cause the levels to rise and fall.

Can you check to see if there are any evidence of leakages on the floors ?

johnfelstead

dont use the fill level indicator as reference. When the engine is cold, take the header tank presure cap off and check to see the water is to the top of the header tank.

If it's an early car the header tank was made of a composite material, these can split and leak under presure, it's a common fault.

Water levels inside the system dont change with the action of the thermostat, the way the system works is it relies on the header tank being full, and then the presure cap releases once a set presure is met to allow water to expand out into the level indicator bottle, when the engine cools it sucks some of this water back in.

If the header tank splits this action stops and you can end up with water in the sight bottle, but non in the engine, so always check the levels when cold in the header tank.

Nexuas

Sorry for the longh delay in the response but have been off work and so have had no internet access.

When you say header tank, which bit do you mean. This is an MY98 sport. There is the clear(ish) plastic tank on the side of the radiator with the max/min level marks and then there is the radiator which has the orange pressure cap.

I opened the radiator while it was cold and you can't see the water level as the hole goes round a corner into the radiator, it topped up the level to see how low it was and got about 1/4pint in before the radiator was full, but I have been having to keep topping up the clear tank to maintain a water level between min/max?

And no the clear tank is not the windscreen washer tank, that is a different one