Please excuse a long post, but I want to give as much info as possible as I am absolutely stumped!!

1st, I think the car has probably had a cooling issue for longer than I know. It's my son's car and he has owned it 4 years and done very well with maintenance, but I think there was a problem he didn't notice until it was way too late!!

He called one night and said the car had started to smoke and it got way hot. Botttom line...the engine locked up and was now toast.

Found a 60k mile 1996 Camaro LT1 engine and had a guy install it. As we had installed a new GM waterpump 2 years ago, I had him install the pump on the new (used) engine. After the installation, he said it was running warm, but not unsafe hot. So we picked it up, and sure enough it was running warmer than I was comfortable with. Also the radiator fluid had a major rust color to it. (I would guess the engine must have set awhile with water in the jackets?) Anyway, did a flush and ever since the heating problem was into the dangerous range.

Ever since I have been on a parts changing binge!! New GM radiator, rebuilt waterpump, 180 thermostat and new radiator cap. All things were done individually, in other words the system was filled with radiator fluid and bleed each time and when that didn't fix the problem, the next part was installed the procedure repeated. If anything the problem seems worse now than ever. It is undriveable, due to the very high temps it will run. I have checked for antifreeze in the oil and vice/versa and nothing and no smoke of any kind. So I don't think it's a head gasket?

I am at a loss. Both fans have been verified to be working. The one thing that bothers me a lot, is the fact that if you squeeze any of the radiator hoses you can't feel flow. Even when pinched down to nothing, I can't feel any flow trying to get through? Is is possible that I would have two bad pumps?

 

Is the waterpump drive shaft in place/splines in good condition?

 

I wondered this too. Both pumps splines looked fine. Even began to wonder if maybe the shaft coming off the cam had maybe somehow snapped, thus not spinning the pump? So tried to turn the shaft with pliers and it would not turn (so not snapped). Started car and verified that the shaft was turning.

 

Why cant I feel the antifreeze coming through any of the hoses?

 

Pull the cap off (cold) start it and let it run while looking into the radiator, as it gets hot some coolant will rise up and spill out untill the t-stat opens, once it opens the level should drop and you should see some swirling, raise the rpm to 1500 while looking (carefully) to verify there is good coolant flow. If there is this elimnates the t-stat and water pump as issues. If the temp guage is climbing and you dont see any flow and it keeps pushing coolant out back away and shut it off...let it cool. It could be an air pocket and you may have a steam bomb...be careful!

 

How are you bleeding it? I believe you have an air lock.

 

To the question of bleeding. The car was on ramps with both the bleeder screws open and no thermostat. Filled radiator until full. Started car and let it run for a minute, took off cap and refilled and re-opened bleeder screws. After running car a time or two for a minute or two and re-opening bleeder screws I put the 180 degree thermostat back in. Basically after that I just ran car while still on ramps and refilled radiator until I was sure that thermostat had opened and system should have be fully purged of air. But maybe I missed something?

 

Make sure that your steam hose and your coolant res hose are not backwarrds on the upper passenger side of the radiator. The hose from the coolant res should be on the tube on the highest part of the radiator, just below the cap and the steam tube hose should be on the tube just below that.

 

I had previously checked the coolant reservoir hose during the flush process, and it is going to the neck just below the radiator cap. As for the steam hose, I can't say for sure where it may be going. I finally got fed up with the whole thing and dropped the car off at the shop this morning. I'm hoping they will have better luck then me??!?!

 

Sorry to hear about your luck...

1. It could very well be the waterpump, you may want to replace it.
2. Im sure that you have done this, but could it be possible to have air in the system.. Try bleeding it again

3. Putting in a 180 or 160 T-Stat isn't going to do much until you get the cooling fans to turn on at 180. The factory has it set to turn the fans on high at 220, i believe... You can purchase a programmer to adjust your fans. Highly Recommend

4. This doesn't sound like it's your problem, but I would check the catlaytic converters. If they get clogged the heat just backs up.

I hope that this helps.. good luck

 

I dunno... I just bled my cooling system while the front was in the air (first time I'd done it with front in air) and I had nothing but problems trying to get air out. I've always done this while the car was on the ground and it's always gone smooth.
Do you see a steady stream of coolant coming out of the coolant/steam return line into the radiator? Not sure if I saw where you listed actual tempterature, but what is it you consider dangerous?

 

Are the fans actually turning on from the heat? If the sensor on the front of the waterpump is bad it won't kick the fans on, however the fans will still work if you max out the AC. Mine was running dangerously hot for a while there until I ran a manual fan switch for the time until my waterpump temp switch gets in. Is it running rich too?