I keep filling my radiator and the coolant has to be going somewhere, I did pressure test my cooling system at my second job and it was holding pressure it dropped a couple of lbs but nothing bad. Whats the possibility I have air in the system because when I broke my belt I ran it for a couple of miles then pulled over and it was empty. But I had this problem before i broke my belt coolant's dissapearing and it's got me scratchin my head. I know that gm radiators have a problem with their end tanks cracking ever so slightly. BTW I have no drippy drippy underneath the car either. How do you know if your t stat and gasket are working right? What about my water pump or radiator i'm running about 20% coolant and 80% water before it was 50 50 then i started having this problem so I dont wanna put coolant in if it keeps dissapearing. It only seem to overheat on 95 at 80mph if I let of and let it coast for a while the temp drops, also my trans just started to overheat as well could the two problems be connected because I know that the trans cooler is in the radiator. Yesterday at like mid day I was seeing trans temps of 230 degrees but when let off the temp drops. Should I flush it and put new coolant in how can I tell if I have air in the system? I think I might have a clog or rust somewhere effing up the cooling jackets in the heads etc etc.

 

Ok I think I might have gotten all the air out, I opened the cap and the radiator was full which the past few times a while back when i did it was empty, How much air might i have had in there?

 

What is the level of the fluid in your overflow tank? A siphon exists between that tank and your radiator. If your reservoir is low or you have a bad siphon (cut line, bad radiator cap seal, etc.) then it can upset things and mess with the level.

 

it was overfilled the other night now i dont know how full it is when i cracked the cap last night the overflow started to well overflow out of the cap. but when i looked at it tonight after work i think it was back to the level where it was supposed to be.

 

There is air in the system, same symptoms as I had. High temps, coolant gone missing and over flow filled to the max.

Did one of those prestone flush kits and run straight water and water wetter now, doesnt over heat anymore.

 

could it be because i ran it dry one day by accident not realizing i had run out of coolant? And another time on 95 when i broke a belt and decided to keep driving. I think it's fixed now because like i said i came out of work and popped the rad cap and it was full and 10 minutes later i pulled over and checked again and it was full the only problem is i'm 20/80 now I'm more water then coolant.