LT1 Running Hot

[pontiacgp]

When I install a new thermal fan switch I test the temperature with a infrared temperature gun and use that to gauge the accuracy of my gauge. What fan set up do you have?

 

[1979Calais]

I just thought about something. the computer has its on temp gauge (connected to water pump) and the cluster has its on temp gauge (driver side head). Don't know if that makes a difference.

 

[1979Calais]

When I install a new thermal fan switch I test the temperature with a infrared temperature gun and use that to gauge the accuracy of my gauge. What fan set up do you have?

Turbo Buick Dual Fans with Caspers' Hi-Low Fan Relays
Also just found out that the fans kicked on at 195.

 

[Ribbedroof]

Did you install the coolant crossover on the back of the heads, or were the holes plugged?

If the crossover is installed, to what is it connected?

Who assembled the engine, who supplied the head gaskets and do you have records of what head gaskets were used?

 

[1979Calais]

I have the steam line connected to the heater hose going to the return on th water pump. The engine was put together at the machine shop, but I don't know what brand gasket. I have the box in my shed and will check tomorrow.

 

[1979Calais]

One last thought on the water pump coupling, mine is (1994) there is a small O-ring on the shaft sticking out of timing chain cover, that holds the coupling on, I replaced this O-ring along with the seals also, in the directions that came with the gasket (seal kit) it stated to install the coupling onto the shaft coming from the engine and make sure it's seated on the splines then install the water pump, it may be possible to install on the water pump and it not be seated on the splines of the drive shaft. Also there is a groove on the OD of coupling, the groove side goes towards the block. See picture

So I received a text from crucial118 today asking me if I was sure about the coupling. I took the water pump back off and seen the coupling was not turned the right way. I will be testing it again this weekend. I hope that's the reason its running hot.

 

[Mat1227]

Lets hope that's all it takes, low cost repairs. Good luck.

 

[1979Calais]

Got the temp to stay at 200 tonight, so it could have been the coupling that was making it over heat. Also there is still air in the block, because the antifreeze is not flowing out of the bleeder screw like it should.

 

[1979Calais]

240* isn't that hot for an LT1, they like heat.
Are the fans coming on when they're supposed to?
Were any of the temp settings messed with in the ecu?
Are you using the LT1 coolant tank?
If you're using a G-body radiator, what about the radiator cap?
LT1's run a closed system, so if that cap is venting under pressure, then you're going to end up chasing your tail.

This is the cap I have, so do I need to change it?