Hi All, I have a 2005 Vette with a 6.0l in it, a couple weeks back it started running hot it went past the factory set 192 degree stat and jumped up to 242 degrees by the time I got the car back to the house and shut it down. After that I replaced the stat with a new one and the car is still running hot, I put the old stat in a pot of boiling water and verified the stat was opening, the fans come on when it reaches temperature so I know that's not the problem. I set the inside heater up to it's highest fan speed and temperature setting to see if I got hot air out of the lower vents and all I got was cold air so I figured I had a bad water pump. Today I replaced the water pump, new upper and lower radiator hoses and unfortunately it's still running hot, it went to 230 degrees before I shut it down, and the heater is still blowing cold air, the antifreeze level in the reservoir is full and it never lowered when the car reached 192 degrees, so i'm thinking maybe it' air bound, when I put the stat in I did install it with the air vent facing up I don't think I have a clogged radiator the car only has 40000 miles on it and I flushed the system 4 or 5years ago the fluid looked good then and the antifreeze I removed today still looked good, the only thing I can think of is possibly it's air bound can anyone tell me how to purge the system of air or if there's something else I should be looking at. Any help would be appreciated i'm hoping I don't have to bring the car out to a repair shop.

 

Start the car with AC on, and make sure that the raditor fan is running.
A/c will turn the fan on, even if the motor is bone cold.


If raditor fan is not running, then start by checking the power connector for the fan,
The connector is on the back side of the radiator, on the passenger side and has the red dot on it in the photo.
Attachment 48334002

When you pull the connector apart, pray is not melted to hell.


If connector is not melted, then will need to check the connector on the PWM on the bottom of the raditor back side plastic housing to make sure its not melted, then the check that connector for power and ground, to weed out if the problem is just the fan needing to be rebuilt or replaced, Bad PWM, or problem up line to the ECM instead.

If fan is running, then may be half way out of the wood.
Hence get under the noise of the front fender, and see if you sucked up something that is blocking the front of the heat exchanger in front of the radiator to start with. Next since this a 2005, might have pop the top plastic molding of the radiator cover so you can move the heat exchanger forward to clean between the back of the heat exchanger, and the front of the radiator that may be blocking air through both as well.

As for heater not blowing hot when the car over heats, screaming that you still have air in the radiator fluid system. Some on the T stats lack the weep hole to allow the air to bleed correctly, while some have the Weep hole not TDC so it can get all the all out of the system. Either way, to get the system to bleed correctly if the T stat weep is positioned correctly, you need to put a vacuum on the tank with the car idling/warming up to draw the last of the air out of the system.

 

Is it possible the sensor is reading incorrectly?

 

Thanks Dano, Yesterday when the car was running I could hear the fan come on,but I didn't physically look to see if it was spinning, so today I will check that and if the fan isn't spinning I will look at the connections, when I installed the stat I was careful to make sure the weep hole was up in the 12:00 position, as far as putting a vacuum on the reservoir, at this point the reservoir is full should I empty the reservoir first and then put the vacuum on it, or just suck the fluid through the wet vac, I feel like I just asked a stupid question but I've never put a vacuum on a antifreeze reservoir before. Thanks again for the help.

 

What is your definition of full. Cold should be at the level line on the front of the tank. Remove some if is totally full.

 

I agree with the others, sounds like air in the system.

I don't know if you have to pull vacuum on the reservoir to bleed it, I would think you could run it with the reservoir open like most cars, but maybe that'd not the top of the system? You say you t Stat has a weep hole pointing up, do it have a steam vent with a screw? That's how you would bleed it...

 

That's correct the fluid level is at the level lint at the front of the tank
no screw on the stat just a weep hole
temps here yesterday in NJ were at 32 degrees today should go to mid 40
and I do have the car parked on a incline and I will try leveling it off and see if that helps

 

Take the fan cover off and look down between your radiator & a/c condenser. The two at the angle together is like having a mini hoover vacuum cleaner. It will suck up leaves and grass and anything else you can think off.PS And get into the radiator fins and block the air flow.

 

Pressure test you system and look for any leaks anywhere

 

Thank You Everyone for all the help, pulled the car out of the driveway and leveled it off , my driveway has a small incline, anyway started the car up and filled the reservoir and let the car heat up and finally the thermostat opened and the water started pumping through the engine, I guess the incline was stopping it from working anyway drove it down the parkway and the temps are staying in the 195 -205 range. I will keep an eye on the fluid level in the reservoir for the next couple of days but so far all's good.

 

I also use VP Racing water treatment in my cooling system and it really helps. I replaced my stock radiator at the end of last year with a Griffin 2 row 11/4" tubes and went from using Redline water treatment to the VP Racing water treatment. And I brought another bottle of VP water treatment last week I will put in in May. I learn the water wetter really helps in my all aluminum race engines & the LS 3 is all aluminum. You can't go wrong using the water wetter even if you don't have a overheating problem.