So I was driving along and my check guages light came on. I look at my temp guage and it's going into the red. I'm like O-crap so I pull over and come to a stop and i'm about to turn my car off when the temp needle goes down to normal in like 3 seconds. It just dropped right down. So I decided maybe it was just a glitch. So I continue on and decide to pull into a parking lot and pop the hood. I notice where I did the tb bypass a few days ago that there was a slight slit in the hose and i could see a little bit of coolant bubbling. So I cut the line after the slit and reconnect it. Problem solved or so I thought. I'm driving again and the check guages comes on so I was waiting for a spot where I could get off the road and then it went right back down again. So what is up with my car? Could I have air in the system? If so how do I get it out? Or is it something else?

 

Did you bleed the system after you did the bypass?

 

You have air in your system and need to bleed it out.

Ken R.

 

Alright that's what I figured. Can I just open the bleeder screws and once coolant starts coming out that means all the air is out right?

 

that happened to me and guess what blown hjead gasket the next couple days... good luck with that...... but now im getting a LE2 setup so im happy

 

Check your coolant level when the engine is cold.

 

Ok so I went out and bought some coolant to add to it. I filled it up to the filler neck and also added to the resivor. Started my car up with the cap off and the the bleeder valves open and let it run. Coolant came out of bleeder valves so i closed them and put the cap back on. Drove around tonight and it was right in the middle of the temp guage all night when all of a sudden I smell coolant. I stop my car pop the hood and coolant is flowing out of the the resivor cap and the radiator cap. So I had to buy some more coolant and fill it back up. It was running fine and I got to a parking lot and shut it off. Few minutes later i turn it back on and I drive it over to Mc.donalds which was like a 20 second drive and it already climbed back up to 260. I shut off my car again wait a few and start it back up and it goes right back down to the 200 range and stayed there until i got home. So what's causing these random spikes to 260?

 

Your car can't all of a sudden cool off from 260 to about 180 in 3 seconds

First off i'd think you would have cracked your block if it cooled that fast, but who knows, these are tough engines. But if you're getting random spikes to 260 then back down, i'd check the temp gauge sensor in the driver side head. It might be faulty and causing different readings. I think it's like a 20 dollar sensor or around there. You can check out shoebox's site here, just scroll down until you see "Testing the ECT (Engine Temperature) Sensors and Connections". That part talks about the sensors for the fans and the sensor in the head.

 

Yea but one time when it hit 260 coolant started pouring out of the radiator and resivor cap. I swear my car will hit 260 and then like in a matter of seconds the needle will drop back down to 200-210 mark. I know it's crazy and I don't see it being possible for my car to drop 40-50 degree's in a few seconds but according to the guage it does.

 

You might want to test or replace the radiator cap.

 

I filled my car back up with coolant today and I think why it overheated yesterday was because when i took off the cap to fill it up then I didnt tighten it all the way. So i guess that could have caused it. It was running about 15 degree's higher then usual today but i'm happy with that since it stayed there and my trip to work is about 40 minutes so it didnt overheat within that time period. Thanks for everyone's help

 

i had this same problem..it bugged me so bad i couldnt sleep..i bought a 160 Thermo. and i eventually talked to GM about it, and they said that it was totally normal for the Camaro's stock Thermo. to go up to 245-250 and it will go back down.....but if it is at the redline just keep your eye on it...our gauges are probably a little off so it looks like 260...i think its stupid...

 

your car can't, but the sensor can if there is air in the system, the air pocket will cause a high temp reading(will be air/steam), then when the liquid coolant hits the sensor, it reads the coolant temp(180-190)