Normal Coolant Consumption

[tucsonjwt]

I think coolant level should never go down in a properly sealed cooling system. Am I wrong? I seem to lose about 1 pint of coolant every 2 months. I cannot find any leaks. Could it be leaking internally and going out the exhaust pipe? I see no white smoke. Coolant reservoir was replaced several years ago and seems to be intact. I did have a leak in the front of the intake manifold at the gasket, but bars leak seems to have fixed that a couple years ago. Temperature gauge remains constant at about 160 degrees (I have a 160 degree thermostat) with only city driving. Coolant looks clean, nice and green, and no milky appearance or antifreeze in the oil. Radiator, water pump, fan clutch replaced last year. Any thoughts?

[J Knight]

I haven't lost a drop in 2.5 years of daily driving. Try to pressure test it overnight.
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[gchemist]

If you are loosing coolant, check the radiator cap. Yes, you should loose some. You live in a very hot climate. When you turn off the engine, the water pressure builds up. The exces pressure is vented through the cap into the resevoir. When the radiator cools, it should suck water back into itself.

You are loosing water through evaporation at the resevoir. A little goes back into the engine. The rest is lost by evaporation. Your truck is fine. Just top it off.

[tucsonjwt]

gchemist - I like your answer.
I think there is some evaporation from the overflow reservoir since that part of the cooling system is not sealed. Out here with 107 degrees in the shade, plus more for hot engine temperature under a closed hood, I think the temperatures are very high.
With no visible sign of a leak, I think I will just continue to top off. About one cup of coolant per month does not really seem too excessive (plus, I am too cheap to chase down/repair another small leak)
Good thing I bought all of that Peak 50/50 antifreeze for $.99 per gallon from ACE hardware over the past few years.

[slinginrods]

radiator cap is the usual culprit of lost coolant that doesnt show up under a pressure test.you can check the cap if you have a tester.the coolant just evaporates over time.

[motornut]

don't get that kinda heat here
may want to wipe around the block,hoses under it with a clean rag
or place news paper under it after a drive