Coolant loss (even when parked)

[russellphoto]

Could somebody give me a hand working out where the coolant is going?

I've had my S1 for about 5 years now and the engine has been without problems. The last time I was out however, the engine temp was climbing towards 110 just as I was reaching home. I let it cool down and checked the next day and found the coolant empty which I topped up to the maximum again. Having checked again a couple of days later without using the car, it was empty again. This time I topped it up and tried to see where it was going - it is leaking constantly but slowly - so slow that I can't see anywhere that its coming out. Can anyone give me an explanation? Is it likely to be serious (i.e costly to fix)?

I just want to have a rough idea where and what the problem might be before I take it to someone to fix.

Thanks

Russell

[robin]

The cheapest place to start is with a new pressure cap for the expansion tank. If the pressure relief valve has failed then the coolant system will vent when under pressure/temperature and you will lose coolant slowly (and the system will possibly overheat too).

The radiator, heater matrix and bleed valves can also weep.

What year is your Elise? Before around mid-98 there was also the possibility of a leak in the coolant pipe that runs up the chassis rail on the driver's side. This coolant will then pool and soak the spongy bricks they used for spacing the pipe away from the chassis and you might never notice the leak until it lets go properly. Unlikely even in pre-98 cars to be honest.

There is always the head gasket failure that can allow coolant to leak into one or more cylinders during cool down. If this is happening you might notice a slight misfire on first start, one or more of the spark plugs will be steam cleaned and you may also notice more steam out of the exhaust than normal (though this is really not a good indicator as so much depends on outside temp/humidity anyway, so don't panic just 'cos there is steam from the exhaust).

A pressure test on the cooling system once warmed up (but not hot!) might reveal at least that there is a leak - if the system will not hold a bit of pressure there must be a leak. Don't go mad though - just a few PSI is enough.

Cheers,
Robin

[russellphoto]

Thanks for the reply

The car is from 2000. I will start trying to track down any obvious leaks and I haven't noticed any more steam out of the exhaust than usual for this time of year.

If it is the head gasket, a friend of mine suggested using K-Seal??? Any experience of this?

Thanks and I'll keep posting where I'm up to with fixing it

Russell

[robin]

First off, here's hoping it is not the head gasket. I don't know what K-seal is but it doesn't sound likely to be a solution ... there are many theories about what causes the head gasket to fail (or the head or block either side of the gasket), but I've never seen anybody suggest you can fix with a sealant. K-seal might mask the problem for long enough to sell the car, but that would be very unethical.

On a 2000 car it won't be the chassis rail problem as they corrected it sometime in 98.

Cheers,
Robin

[hiscot]

yes my 97 car suffered the chassis rail problem , the rivet would also reseal the hole it made so it only leaked now and again ,give away was the alloy sill got hot when it leaked , later cars gained a different shape rail to clear the rivet's
also check the colour of the plastic inlet manifold gasket I think they changed to green from black a known leak problem you can see the gasket tabs with out removal but check if its black its not just crud over a green gasket