I take the radiator cap off and start my car, let it warm-up to operating temp and watch the level raise and drop by four to five inches. My question is, is this normal and if not, what would be causing this?

Basic info:
'79 LeSabre with a Buick 350. It has a new water pump, thermostat, and fan clutch. It does have a tendancy to overheat, but only in the winter. (Yeah, sounds weird to me too.)

Thanks in advance for your assistance.
John C.

this is normal until the thermostat opens. it takes longer with the cap off. when stat opens you will see a dramatic drop in fluid level.hope this helps.JIMKand you will se fluid running threw the flews.

[This message has been edited by JIMK (edited 11-30-2001).]

Ok, I was now wondering why it only overheats in the winter. (North Dakota Winter to boot!)
In the summer, it does fine. Doesn't over flow into the expansion tank and never boils over, but when it gets cold, it fills the overflow tank and I can hear a boiling sound coming from the radiator after I turn the engine off. This seems to contradict common sense. Any additional info would be appreciated and thanks in advance.

John C.