Radiator questions

[fishrod]

I seem to be missing some radiator coolant. I was under the impression that the engine cooling system was a closed system and that, in a perfect world, you shouldnt really lose any coolant.
I started to lose some a few months back, not alot, maybe 1 litre or so every month (maybe that is alot). I had a service and they did a compression test and couldnt find any leaks.
So where could it be leaking? Im thinking into the engine somewhere, cylinders? and then burning off? I also had the radiator changed about 4 months ago and they checked/replaced any worn or defect hoses so im pretty sure its not a hose leaking somewhere. There is never any coolant puddles or anything on the ground either.

Also, what is the use of the overflow tank/thing for the radiator? Again, I was under the impression that it stored "overflow" coolant and that it would somehow pump coolant back into the radiator if it got low. So far the overflow has sat right on the full line for the past 6 months and hasnt seemed to move one bit! No matter if my radiator is full or half empty!!

:wtf:

Any ideas?

ps, its a 94 with the 3vze engine.

 

[fourwd1]

The overflow resevoir only works when the engine overheats. If it doesn't overheat there's not enough pressure to overcome the rad cap.

Try doing a pressure test on the cooling system and see what happens.

And yes, it is possible a Head Gasket can be leaking coolant into a cylinder and it's burning off, but it's so small it doesn't produce the white smoke normally asociated with a bad HG.

 

[ovrrdrive]

Yep, if a pressure test didn't turn anything up I'd be doing a compression test.