Overheating Issue

[Supra5MGTE]

ok guys, it's not on my yotas, but it's my brothers 2001 WS6 Trans AM. I know this forum has some good knowledge so I wanted to run it by everyone see you guys think.

Ok, the thing is blowing coolant out the overflow. The Temp gauge is reading 210, which is normal operating temp for that car. It's bone stock with 60K miles. It's acting like it's overheating, you can hear the bubling inside the cooling system and blowing out the overflow when it gets bad enough.... but the Temp gauge is reading 210, Normal temp!! the temp sending unit is located in the cylinder head. the gauge has actual numbers on it, not C H. Those cars don't seem to have gauge issues, and the thing looks like it's working as it always has been. WIth the car idling and the rad cap off, it bubbles like all hell is breaking lose and seems to maybe be boiling, but not much steam is coming out with the hellish bubling. For me, it's acting like overheating.. bad Tstat, but the temp guage is FINE! any ideas?

 

[MDCmotorsports]

Wrong car but I'll take a stab at it.

Sounds like a possibly BHG issue and its pressurising (sp?) the cooling system.

 

[JustAnotherVictim]

Did you do a pressure check?

 

[Supra5MGTE]

no pressure check yet. I was hoping it would be a Tstat, but the temp gauge making it read normal is what doesn't confirm the Tsat possibility. I did this morning start it up take the rad cap off and fill it up with water and keep it toped off.. kept bubling a bit and the water level would fall.... fill it back up.... buble again and water level would fall. did this for about 15 minutes. Think that's a bit longer than it would take to purge air out of the system. put the Rad cap back on and let it idle for a bit longer. checked the overflow tank... it was filling up slowly. so my guess is after driving it a while the cooling system bubles or whatever and dumps water into the overflow tank and then the overflow tank fills up and eventually spills out. Sucker wouldn't get past 210F sitting in the drive. that gauge is FINE. When I looked at it this morning it was under 100F. and it rose normally.

 

[mazzer]

with the rad levels rising and falling it sounds like the t-stat is acting irratic. when its at operating temp is the fan drawing hot air off the rad? are both upper/lower rad hoses hot? heater hoses?

 

[Supra5MGTE]

Well i'm gonna put a new Tstat in for grins before we give up and say it's a HG. Thanks for the help guys.

Makes me glad I don't own a car like that. Engine is burried under the windshield and up in the console. Can't pull the motor from the top, have to raise the car on a post lift and lower the engine as an assembly with the front suspension out from under it.:aigo: Screw that. Gotta love GM's thinking. I ditched my '89 Vette for a reason... GM cars suck. Only gm i'll own is a late 60's early 70's muscle car... or maybe a nice RWD 80's Gran Prix/Monte Carlo built up.