85 Riv antifreeze mysterioulsy disappears

[Guest Straight eight]

Since puting the 85 Rivie with the Olds V8 away for the winter, the reserve tank shows a loss of fluid that I would estimate to be one to two cups.

I know this because I had marked the level when I changed anti-freeze a year ago, and have been watching the level.

There are no signs of external leaks.

Does antifreeze contract in the colder temperatures, as it expands when hot?

[Jim Cannon]

Yes it does, but not that much.

It is possible that you have left an air bubble in your cooling system somewhere (heater core, etc.). If so, that air will greatly contract with cold, much more so than liquid coolant.

There could also be an internal leak. Pull the oil dipstick and see if the oil level is rising. Coolant will sink to the bottom of the oil pan, raising the oil level on the stick. But you can't just go by where it is today, you have to see if it keeps increasing as coolant continues to go into the pan.

[sosuzguy]

Hello _____ ?

I have 4 of these cars and for a while after changing hoses or doing anything to the cooling system, for a few drive cycles the level in the reservior tank will fluctuate. As long as it's not getting in your oil or obviously leaking what Jim said about the air bubbles is correct in my experience. Keep a watch on the reservior level for sure.