I have a continuing overheating problem with my '87 IROC. It has a "Golen" rebuilt 350 TPI. It constantly overheats, no matter what steps I take to prevent it. Yes, the spoiler is in place underneath. The car is currently at a local shop, and they haven't figured it out yet. The radiator has been to a shop, "rodded out", hte tank removed and inspected.....no obstructions. The T-Stat is brand new and works properly. The water pump is brand new and has been inspected in back, and pronounced OK. The hoses all are new. The block has just been flushed, with no significant "gunk" emanating from within. There are no coolant or oil leaks anywhere. The car overheats at idle within 3-5 minutes, cools off to normal operating temperature at "city" speeds, and overheats again at "freeway" speeds. slowing down to 35-45 MPH cools it off again, unless I stop at idle for 3-5 minutes. At the shop, they have run it up "hot", switched the fans on, and the motor will NOT cool for them, even with the fans running. I'm at my wits end, and am ready to sell it off to someone who wants to put up with this. Anyone have any ideas? I'm fresh out, and so is the shop.

 

What temp t-stat do you have? And is it installed properly? It sounds to me like one of our T/As when the fan wasn't coming on. If I were you, I would pull the t-stat out myself and make sure it's installed correctly. If it is (hat, pointy side up) then throw a 185 in there just to rule out a bad t-stat. If there's still some problems, then I'd yank the radiator, make sure it flushes fine and doesn't have any blockages (myself, don't let the shop do it) and then if that doesn't work, pull the t-stat and all the hose fittings to the motor and run a garden hose down the top and see if water drains out without problems. If not, yank the motor and find the problem.

 

I would run it without a thermostat and see if it acts different. I gotta admit, this is a strange one. Has it ever run right at one point? And if so, what changed between then and now?

 

Have you tried wondering if it is a reverse flow water pump. Thirdgen's corvette's and suburban's use the reverse flow pump if you are using a standard the pump fins don't do a whole hell of a lot when running. Do you have a high stall converter. If so and your still using the radiator to cool tranny fluid that can cause your collant to get hot. Air bubbles in your coolant could be the culprit too. Make sure the system is completely purged and pressure test the raditor cap and then system. If it drops below the recammended pressure you got a leak.