I know the coolant system is a closed loop but how much coolant usage is normal in what mileage or what time frame? Under normal conditions when the engine is hot and the coolant is hot too how much of it turns into steam and escapes through the reservoir? The owners manual just tells you to add 50-50 mix of coolant and water when close to low.
Othervise no external or internal coolant leaks found with pressure tester.
how much coolant usage is normal in what mileage or what time frame?
0 Zero !
It is normal to never have to add any coolant at all between regular cooling system service every 2-3 years.
Okay 0 sounds good. Then why your manual says to check it periodically and add when close to low? It seems they expect some to be missing over time.
I rented a Jeep on my last vacation. it had less then 10 k on it. Just for giggles I checked the reservoir and it was bone dry. No leaks or overheating what so ever.
So this imply is normal to loose some in 2 or three years. You know the oil change place topping it of at every oilchange unless you tell them not to do it.
Zero is normal, but in the real world leaks often occur. You need to top the system off occasionally. Running with it too low can destroy your engine. My own yardstick has been that if it loses more than a quart a month I repair the leak.
A pint a month, depending on usage and climate, would fall into the “normal” range…The overflow tank IS vented to the outside so there is SOME loss due to evaporation. This is normal, that’s why your owners manual advises checking it periodically and adding a little if necessary…
If you need to refill the coolant reservoir between servicings, you have to start looking for why. With respect to Caddyman’s point that there is a venthole, I don’t believe that evaporation through that should be more than the difference between the Max and Min lines on the reservoire.
Having said that, it’s extremely important that you regularly check your coolant level so that if you do have a problem you’ll “catch” it before you overheat. Many of the posts we get here on overheated engines and subsequent damage probably would not have happened if folks were more attentivet o their cooling fluid levels.
I have found that when I used to fill the reservoir to full when cold then I had to constantly add a little to keep it there. The problem was that when the coolant was hot it would seep out of the overflow tank’s vent. I fill it to the mid to low level and then it stays there for long.
i agree with the -0- comment.
any change outside of the full and low lines indicates a problem in the system. some people may NEVER check the level (until diffylube gets under the hood) but usually by then it’s too late. i think the idea of recommendations to check it periodically are for preventative measure, not monitoring leaks.
BTW, i think i’ll go outside right now and check my fleet. so should YOU!
The only time I’ve ever lost any coolant at all, I found the leak. 40+ years driving and fixing.
I have a reply-question. So I don’t know much about cars or maintenance, but have an increasing interest for rational economic reasons, fuel and other prices being what they are. I have a 155,000 mile hyundai, which stalled from overheating as far as my amateur self can tell. SO i added oil, which it needed, and coolant/bottle water. I assume the thing i added it to is the “coolant reservoir” I didn’t know whether there was always supposed to be an amount of fluid in that thing itself, though i thought it obvious that it should, i wasn’t 100% sure. from this discussion it seems it should have some amount of liquid always. SO i’m presuming my car is in big trouble, because I had to gput more coolant/water in the reservoir like every 20 miles or so. I’d stop, let the thing cool down, and the reservoir would gurgle a few times occasionally, and then by the time i felt it had cooled down enough, the thing was bone dry! so what’s the deal? is it a black car in the summer? is it an age-related engine problem? funny thing is, i had been driving it for a while before this happened, and it wasn’t the most healthy car, but i never stalled, until today in which i had to fill the coolant every 15-20 miles just to make it to park in my mother’s driveway. sorry for the ramble!