S1 coolant...overheating...maybe

[captain]

Well this is weird.

I check oil and coolant religiously, every week. Two weekends ago I topped it up because it had lost about 200ml.

Last weekend I took it out for a drive - had to jump start it (long story - sticky brake switch puts the brake lights on sometimes and flattens the damn battery.) Anyway, after a couple of miles I noticed The car had got to 98C, highest it's ever been. I stopped and checked coolant to find the header tank was completely empty. I put some water in it and nursed it home, temps got to 106C and fan was on but didn't get any hotter.

It was snowing and getting dark, I checked the oil and managed to convince myself it was looking creamy but the dipstick is a pale colour anyway and having checked again in daylight I think it's OK. There were some lumps in the oil under the filler cap but hard to tell what it is.

I didn't get a chance to do anything with it all week but I topped up the coolant today (took 2 litres) and let it idle for a while, temps stable at 85C. Drove it 10 miles over to my mates garage in Kemnay and temp never went over 86C. It did however use a bit of coolant - not much though. I'm getting my mate to flush the coolant and change it with the under trays off to hopefully see if there's a leak.

Any ideas?!

[robin]

Does it misfire/slightly harder to start then clears itself with a bit of a rev? Is the first turn of the starter a bit slower than you're used to? If either or both of these is true then the coolant is finding it's way into the cylinder and being burnt. There are three common causes of that:

(a) Failed inlet manifold gasket allows coolant in through the intakes.
(b) Failed head gasket allows coolant into chamber.
(c) Failed head casting (and/or incorrect cylinder block liner heights - amounts to the same thing normally) releases pressure on the fire ring and allows coolant to escape from the water jacket into the cylinder.

If it's a leak outside of the engine and you lost 2L then there would be a lot of coolant somewhere.

If it's a leak into the engine block then the oil will be properly emulsified if you've dropped 2L into it.

In addition the expansion tank cap pressure relief valve often fails allowing all your coolant to piss out under pressure but only when hot. The rest of the time it'll be fine - but to lose 2L you would surely have notice that the expansion tank was extremely damp

There was a fault with the original inlet gasket and it was replaced - you can tell by the colour which you have, but of course I cannot remember which is which - somebody will know (or call Craig at CMC to be sure).

Cheers,
Robin

[robin]

P.s. I wouldn't flush the coolant - just keep filling it up - in fact to find your leak you can brim it and put the lid back on - this will increase pressure in the system and the leak should become obvious.

[captain]

Thanks Robin, that's really helpful.

Anyone know what's the capacity of the coolant system?

[campbell]

In most K series cars it tends to be infinite...

[robin]

I seem to remember it's 10l but cannot be sure.

[istoo]

In most K series cars it tends to be infinite...

[istoo]

dark blue S1 passing through Insch on Sunday...
Assume it was you, everything running smooth?

[captain]

Aye it was me Iain, didn't see you?

Replaced rad, running fine. Interesting commuting at the moment, lots of icy ruts on the Premnay road. Heated screen is The Bomb though.