When the car is hot stick your hand behind the radiator and see how hot it feels. When my radiator was bad it felt warm but not hot like it should.

 

My car overheats all the time also. The fan switch helped but I think I broke that when I put my headers on. I was out last weekend (cold weather) and it was still overheating unless I was going 45+ for a long streach.

 

Well i took it to a radiator shop and they where pretty confident it wasn't a cracked block/bad head/gasket

They are convenced its a flow problem too.

Today I flushed the system for about 30 minutes and refilled it with a good antifreeze/water mix. Also added a quart of that cooling additive that helps lower boiling point..

Something similar to water wetter

 

Ugh, excuse me while I locate my BRAIN.

 

welp.. Still overheating

I guess I'm going to tear it down and start all over again

Any ideas?

 

I dont know about you but before I pull my heads to check the headgaskets I am going to run without a thermostat for a while and see if that helps. Its summer time now so it wont hurt anything.

 

put a CSI pump on the car today and its overheating still from what i can tell its still overheating..

It did have a small leak... its probally still gonig to oveheat though

 

really does sound like a flow problem man..

the heads on that block wouldn't happen to be stock, would
they?

if they're not, well this is just a shot in the dark, the coolant
passages may not be drilled properly in the heads, causing
bad flow..

it would only happen if someone puts heads on that block
that wern't really designed for that revision block..

like on big blocks, Gen 4 heads won't work on Gen 5 or 6 blocks
because of different coolant passages...

good luck, man.

 

I had very similar problems as you did last year.

If it was 30 degrees outside My coolant temps were like 175, then when it got upto 80 degrees outside, My temps would have raised up to 195. And would continously climp as the weather got hotter and while driving on the highway. I tried the manual fans switch, running 80% water and 20% Coolant, a new thermostat and water wetter with NO Luck. My Radiator had about 110K on it as of last summer and was pretty filthy when we pulled it out of the car.

Over the winter, We (me and My friend) swapped out my old motor for a new 383 motor. We accidentaly broke my old radiator in the process. Fred (Injuneer) came thru with his old radiator that had about 60K mile on it and he had cleaned the fins prior with a compressed air. My Friend and I also clean out the AC condensor (trying to removed all the debris from the fins of the AC condensor). Now, with Freds cleaner radiator and My cleaned AC condensor with a blown 383 motor, On a 30 degree day, I would see 173 coolant temps and on a 80 degree day my temps only rise to 178 on the highway and stay there. Mabee you should clean out the fins on your radiator or if your radiator has too many miles, or you can buy a newer one in the forsale section. I know it worked wonders for my car.

Hope that helps,
Claude

 

Actually the radiator was replaced with a brand new GM delco unit last summer. It seemed to fix it for a while but came back.

I plan on having it flowed/rodded out if it still overheats.

 

my car has been getting hotter than usual as well but today i just found out that the STUPID black plastic thing that sits in front of the radiator, actually i believe it sits infront of the condensor but since my a/c is removed that stupid black thing made its way to sit dead flat on the radiator and that was causing air not to get to the radiator i swear the STUPIDEST things sometimes

sounds like you have got everything replaced though! ONE thing i would definately suggest is i know on my CSI pump there is a BLACK wire (GROUND) and a BLUE wire (POSITIVE) make sure those are correct cause if you install them backwards the pump will spin backwards and cause the water to go the wrong way! also maybe you should pull the pump off and verify that the fins are turning the correct way neways! just a thought

 

Since you said it wasd getting hot on the interstate, have you made sure that all of the factory air ducting is still in place and working right? Make sure the air dam isn't damaged or just flapping back...or completely gone. Also the duct work behind the facsia that directs the air into the radiator, still there and working right?

I would think after replacing the water pump, radiator and stat. that the only thing left to give any kinda of blockage would be the heads or block. If they have been cleaned right and it still does it, and you think its a blockage problem to me the only way to fix it would be to tear it all apart and hot tank the parts. Before I did that I would triple make sure the gages are working right, pull the stat completely and pressure test the system and the cap. Along with everything else one last time since it would take a little while to do it.

One other thing....what about the head gaskets themselves? Might be the wrong part or some of the holes might be getting blocked.

You said you tried a new GM water pump as well, not using the electric motor? Just wondering if the electric pump can't flow enough for the motor.

 

Check your air dam if it has seen a few driveways in it's day and is now deformed it will not direct air properly. Also check to make sure both Black plastic pieces(air-Guides) and properly in place. Make sure that the three black plastic clips that hold your bumper cover to the rebar underneath are in place. When they are together with the air dam and the air guides. It will make more air flow to the radiator. It will cause cold air from the ground to be directed to the radiator, kinda like the top side of a wing on an airplane. I know that these are essential to froper air flow.
Chris

 

This may sound stupid, but make sure you blead the living hell out of the system. When you think you're done, blead it again.

My car would continually run hot or over heat & no amount of flushing or turning the fans on early would help. There was maybe an ounce of air or so in the system & that's what caused it.

Also, make sure all of the stupid plasic things around the radiator are on. They do help.

 

I finally figured it out.

I had put a brand new Delco radiator in the car last year so i figured it must be good. Turns out it had clogged. THe guy at the radiator shop said it was not unusual some brand new radiators are clogged.

I put yet anthor delco radiator in it and it has never stayed colder. I mean with the ac on it will hardly hit the first tick mark in 100 degree weather