hello my name is chris and im a mechanic but this lt1 is pushing my skills I have replaced radiator, head temp sens, water pump and water pump temp sensor thermostat the fans don't kick on till the gauge reads just after 260 but the scanner reads 226 and ive used a laser temp gun and I believe the sensors are reading accurately on the scanner the temp reads 226 wich is normal when the fans kick on but the head is reading 260 so I thought I had an air pocket due to the reverse flow cooling system Ive tilted it on a lift tryin to get this air pocket out but still it allways boils over I have a vaccume fill and stills boil over I use a radiator cap fill funnel and I start with little to no antifreeze in funnel and it still pours out over the sides and every time I burp the screw vents also im stumped here if I leave the cap on and let it idle it hits 260 then the fans kick on and the coolant low light comes on but by the time I can get the cap off (cools down) the antifreeze is up to level it seems like I have an air pocket but why cant I get it out am I doing something wrong ??? are the head passages plugged green antifreeze and when I bought the car I never had this problem it started one day all of the sudden that's why ive replaced all I have but still im stumped and if there wasent a problem I don't think I would be boiling over any one ever had this problem???? helppleas I love it too much to give up on her with the cap off it boils over but with the cap on it seems to be fine not blowing out of over flow tank or any thing im just stumped

 

and I am certain there are no plugs left on radiator witch ive seen ppl do and it appears I have no coolant leaks either if I hit the high way the car stays at 190 but when I stop and idle for a while it does it over and over again and my heat seems to come n go

 

Check out Shoebox's write up here:

4th Gen LT1 F-body Tech Articles

I never knew that the cooling fans wouldn't come on if the A/C wasn't working or not charged up.

 

They won't come on when the a/c is turned on. They will still come on by engine temp when required. I'll clarify the language in the article to avoid confusion.

 

Have you checked the harness for the coolant temp sensor in the water pump, to insure it is supplying 5.0V reference, with the harness connector off the sensor?


[EDIT]
Just notice, you've had thus problem for nearly 2 years, and bumped your earlier thread up to the top. No need to do that. Either start a new thread, or continue the old thread. If you have two active threads you will lose the continuity of help.

https://www.camaroz28.com/forums/lt1...roblem-857693/