Coolant usage - how much is normal?

[rhys.l]

My car has used up about 1/5 - 1/6th of the coolant in its overflow bottle over the last few thousand kilometres. There are no external leaks which I can pinpoint (or evidence of overflow) so coolant must be being lost internally..

Is this anything to worry about? Oil isn't cloudy (it's actually remarkably clear after 4000kms) and I don't seem to be getting excessive amounts of smoke out my exhaust.

PS. coolant level estimated with car on level ground and stone cold.

[bennjamin]

The coolant system is sealed so it should not use any fluid at all.

Any usage points to a leak , be is obvious like a weeping hose clamp joint or hidden like headgasket issues.

Try bleeding the air from the system , top up make sure no air bubbles and monitor it again. Also look for white or yellow powdery water marks on the engine or around hoses , around water pump etc - these can point to a leak

[grifty]

i find that in summer the coolant level goes down about around 50ml every few thousand.

i think its just normal as the overflow is not sealed and when the radiator releases excess coolant some of it is vapourised because it is not under pressure anymore. Also dont forget the boiling point of the coolant is higher inside the radiator because it is under pressure.

[Bludger]

i find that in summer the coolant level goes down about around 50ml every few thousand.

i think its just normal as the overflow is not sealed and when the radiator releases excess coolant some of it is vapourised because it is not under pressure anymore. Also dont forget the boiling point of the coolant is higher inside the radiator because it is under pressure.
plus one

[rhys.l]

Cheers guys. Yeah I thought a little bit of loss was normal. But I think I am losing more than what can be explained by vapourisation and there are definitely no external signs of leaks anywhere (liquid, powder whatever). Guess for now I will just monitor it and suck up the cost of the oem coolant.

[Bludger]

How long has it been going on?

if it has been a while and your oil still looks normal then open up your oil cap and shine a torch inside have a look.

Have a look on top of all the valve train and cam caps if you can. Look for creamy cappuccino like substance.

I would not monitor with oem coolant, too expensive. just use cheap coolant if you plan on finding the problem and fixing.

[migoreng]

I drive a BB6 Prelude. The overflow tank goes from max-min in about 10,000km..I bought a 2L bottle of Coles demineralised water for topping up.