Cooling system flush question

**JayTA98** · 01-29-2011, 07:39 PM

Ok thanks. I'll keep an eye on it.

**JayTA98** · 01-31-2011, 06:56 PM

No more low coolant. good to go.

**toplessLS1** · 07-23-2011, 06:05 AM

Have 1998 Z28 with 74,000 miles. Car runs hot...a tick past the 235 mark (in between the 210 and red zone.) Flushed system. Charged with Dexcool. Still runs hot. Burped system, but tell me if I am doing it right please.

Run with cap off. See small air bubbles come out. Temp rises and tstat opens more bubbles and then overflows. Coolant all over the ground. Shut off engine. Coolant level drops. Add more coolant to top off. Seal cap and still runs hot. Any ideas?

**JayTA98** · 07-23-2011, 06:42 AM

Originally Posted by toplessLS1

Have 1998 Z28 with 74,000 miles. Car runs hot...a tick past the 235 mark (in between the 210 and red zone.) Flushed system. Charged with Dexcool. Still runs hot. Burped system, but tell me if I am doing it right please.

Run with cap off. See small air bubbles come out. Temp rises and tstat opens more bubbles and then overflows. Coolant all over the ground. Shut off engine. Coolant level drops. Add more coolant to top off. Seal cap and still runs hot. Any ideas?

did you change the Tstat? When i do it I start the engine with cap off. I let it run until it starts to get hot. after a while The tstat opens and the level drops. then I add as necessary but it doesn't overflow. I also remove the small hose that goes to the bypass tube on top of the engine and fill up with coolant until it purs out of the tube. I reconnect the hose and then start the process with the cap off.

**toplessLS1** · 07-23-2011, 07:06 AM

Thanks for reply. No I have not changed the tstat.

Since my last post I tried removing the bypass hose and made sure there was no air. Check. I massaged the upper and lower hose and that seemed to make a difference. Also ran the heat wide open. Level dropped a little and added more coolant. Continued until I saw no drop in level. The radiator still overflowed as the temp reached 210. I installed the cap and let the engine warm up some more to see how hot it would go.

Update. Thought I had it licked but it still runs too hot. Up to 240 at lunch. I suppose it's the tstat, but not sure. Will change it out once the engine cools.

**35th-ANV-SS** · 07-23-2011, 09:48 AM

Water pump, t-stat, or your fans are not coming on.

**JayTA98** · 07-23-2011, 10:16 AM

good point 35th. are your fans working? I will still change the tstat.

**toplessLS1** · 07-23-2011, 11:28 AM

Thanks guys. It was the tstat. Replaced, burped and now running cool. This is a great site. I checked the fans and all the posts and links on how to burp the beast and change the tsat. Good stuff.

**JayTA98** · 07-23-2011, 11:30 AM

Originally Posted by toplessLS1

Thanks guys. It was the tstat. Replaced, burped and now running cool. This is a great site. I checked the fans and all the posts and links on how to burp the beast and change the tsat. Good stuff.

Glad to hear that you figure it out.