Should a car like my XR8 use coolant over time and need top-ups?
I ask because it does go through some coolant - always has since new, but I've never worried too much because it doesn't use heaps. Probably 100ml per month is the most it would ever consume - usually it's probably less than half that (consumption rate seems to decrease as the coolant level in the resevoir decreases). I've pressure tested it before and although I'm uncertain of the accuracy of the tester, it seemed ok (tested when cold though).
As I think about it, I figure that (theoretically) the car should never consume any coolant because the only way it could use any coolant (if it's got no leaks) is by loosing it as vapour through the pressure cap, but it'd have to boil for this to happen and with proper coolant, it should never boil. Of course, theory is not always the same as reality and maybe there's stuff I haven't thought of.
So the only thing that worries me, is maybe my car does have a small leak somewhere at high temp. etc and if it's in the engine or heater core or something that would be the worst thing. So should a car with my type of cooling system use any coolant normally? If so, where does it go and how much consumption is normal and/or how much do other ppl with similar cars go through?
Steve, my TS50 220kw uses a little coolant too, my EL XR6 use to use alot.
My TS needs a top up only when i service her.
The rate of loss is: every 10,000km's it is between the half way and max level.
If you have tested it and seems OK, i don't know what else you can do.
My XR6 had a leaky radiator, but also tested OK. (rubbish plastic ends)
TICK4D - that rate of consumption is probably a better and reasonably accurate way to describe mine as well.
Rollin - your theory of water particles venting with the air as the pressure builds makes sense and that's the only way I figured (assuming no leaks) that it could happen too, I just was thinking the coolant would have to boil and create steam for that to happen, but the way you put it seems to make more sense and I guess it's true that the coolant wouldn't have to boil as such just for some of the water particles to become atomised at operating temperature (I wish I could remeber all the physics stuff I learnt at high school :)
Anyway, sounds like it's probably pretty normal then. Makes me feel a bit better
Interesting snavy. I've really gotta get some proper 'consumption rates' for my coolant - can be a bit hard to test though as the consumption rate seems to decrease exponentially as the level decreases. Sounds like your parents EL was doing alright at that rate though.
a bit of physics for ya; water starts to boil at 88 degrees right up to a steady constant boil at 100. this is of course without coolant but even if the temp was low90's with coolant it would still partially steam off. cant add anything else that hasnt already been said. hope that helps
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I was told a long time ago by a radiator repair company that the cross-flow
radiators don't accept "over-filling", and will therefore spew out any excess
coolant via the overflow tube. This might explain why the consumtion decreases exponentially as the level is decreased. I have both an AU2 Futura and an NA Fairlane. On both cars the level will always remain constant, near the "min" level mark. If I were to fill both to the "max" mark, within days the level would drop to just under mid-way between "min" and "max". All coolant level observations taken when the engine is cold, naturally.
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