Coolent loss?

[Drew99GT]

My coolent level in my 94 Corolla seems to have gone down ever so slightly, but I have no outward signs of a headgasket leak or an external coolent leak. Is it normal to continually lose a slight bit of coolent from evaporation at the overflow blowoff tube? That seems to be the only spot that is truely open to the atmosphere in a closed cooling system. Also, the level has dropped since the weather has started to cool off in the fall. IE, when I check the level in the mornings in my garage, the temperatue in there has probably been 10-15 degrees cooler when I check it than during the summer months. Would the coolent level be affected that much by decreasing ambient temps like that? Thanks guys.

[ September 25, 2003, 02:50 PM: Message edited by: Drew99GT ]

 

[Amkeer]

Keep a close eye on the levels and check it at least once every three days or so. I would mark the overflow battle at its current cold level. You may need a new cap.


Daily Drives
-2003 Toyota Tacoma PreRunner XtraCab, Impulse Red, Peppy 2.7 Liter 4 Banger, Running Mobil1 Synthetics SS 5W-30.
ODO 5000 Miles.
-1995 Toyota 4-Runner, Evergreen, 3.0 V6, Running Mobil1 Synthetic SS 10W-30.
ODO 81700 Miles.

 

[Drew99GT]

Already marked the bottle, has a new cap and thermostat

The loss of coolent has honestly only been about at most 1/4 to 1/8 of an inch below the mark I made, in a span of probably 5,000-6,000 miles. So I thought about it, and the only thing I could come up with is that the weather has been cooler here since I made the mark on the bottle, which was back in June or July. Any truth to my hypothesis? And can any evaporation of the coolent take place at the overflow tank?

 

[Spector]

Yes, cold weather affects all liquids and it will cause the level to change (it does on mine). Also, I personally feel that the tanks with air outlets/inputs do have some evaporation over time. keep monitoring it. On one of mine if I start the car within/before 24hrs after shutdown the level is constant, if I let it sit 36 hours the level will drop some, really strange.