I checked my coolant level the other day and saw it was a good 6" below the radiator cap throat so I added some. I filled it to the top and then had it overflowing back out the overflow tube after the first long run. It's now down to about 2 or 3" below the rad cap throat. Is this normal or, is the spring in my radiator cap going and needs to be replaced?

The current cap on it is a 13lb cap.

Thanks.

 

Not unuusual for the coolant level to be down an inch or so, but if it continues to expell the fluid to 3" or more I'd start with a new cap. Does your engine run hot?

 

I run a 16 lb. cap without an overflow tank, and without getting any burps. Make sure your cooling system is in solid condition before upping the cap rating.

 

Nah, it doesn't run hot at all. Stays right between 185 and 190.
I'll try a new cap and see if it makes a difference. For a few bucks, it wouldn't hurt to try.