I've got a 95 Z28 and it's fairly stock. Here's the problem. When sitting in traffic or just being in city traffic the temp gets up to between the third white mark and the red mark. When I get going about 45mph or faster then the temp starts to drop to about halfway. Sense then I've put in a new waterpump, new thermostate, new radiatior cap, new hoses, bleed system numurous times and put in a manual fan switch hooked up to both fans on high. When the temp starts to climb close to the 3/4 mark I flip the fan switch and it gradually goes up to just past the 3/4 mark and stays there. And never gets any cooler untill I get up to highway speed. Now, I've done a search and read severaly threads and have come the the conclusion that I need to get the radiator flushed next. Can I do it myself or should I have a "professional" do it. And also should I try to go with no thermostate?? What should I do guys??? I planning a trip that I will be in alot of bumper to bumper traffic and am affraid that my car won't make it through it. Thanks for all your help.

Shawn

 

Are your fans coming on when they should be? Stock low-speed kicks on around ~215, and high speed around ~235. These cars are designed to run hot, but consistently on the 3/4 mark? Something doesn't add up.

What coolant are you using? Stock/stuck thermostat?

Is it possible that your waterpump is bad?

 

Using solvents to flush an old radiator might be a bad idea. 8 or 9 years worth of gunk that is potentially holding your radiator and heater core together will be flushed out with a solvent. Flushing your system chemically might lead to many more cooling problems, and will most likely result in leaks. I had some VERY disgusting coolant in my 94 Z, and my temperatures never got that bad, even in stand-still traffic. The fans always kicked in when the temp rose slightly above the halfway mark, and this is in DC bumper to bumper traffic. You may have another cause of overheating. Hold off on getting it flushed until someone gives you a very good reason to. When you took off your water pump, you should have replaced 85-90% of that dirty coolant with fresh coolant, so your temperatures shouldn't be anywhere near as bad as they are. I'm not sure flushing is going to do it for you. Maybe your thermostat's screwed up.

 

Thanks for the info guys. Today I was checking everything out and found my problem. Only one of my fans was working. I crawled under my car and wiggled the plug on the non working fan and it started working. Today on the way home from work I kept my fans off until it got up about the 3/4 mark sitting in traffic and then turned my fans on and and temp went down to the 1/2 mark. So that took care of it. Thanks again guys.

 

If you have the system "professionally" (loose use of the term) flushed, then they should be flushing clean fluid into the system and sucking it out at the same time. Therfore getting rid of all the gunk and buildup. That may be what you need to do, Bryan, to get that last little bit of EG that we can't get out of there. But I think we can manage with a garden hose and an environmentalist tied to a tree.....

Glad you got it fixed, Shawn

BTW: Thats a real pretty site you've got set up there. I hope it catches on. It looks promising....