I have a ls1 in a 87 Trans Am. I am using a 3rd gen radiator. I have a autometer sending unit that connects to my stock temp gauge. I have a 160* stat. Sometimes, the cars rans at about 160*, sometimes at 220*. The gauge could be off, I know. what can I do to keep the temp from flexing so much?
Yesterday it stayed at 160* all day! Then I left my buds house at 9 pm and it went to 220 and stayed there all night.


Should I get a 4th gen radiator?

 

4th gen rads are no better. In fact I think they are smaller. Sounds to me like you have air in there somewhere or a sticky thermostat. I've had brand new thermostats give me grief before but I'm betting on air in the system

 

I would check you fans and make sure they are coming on when they are supposed to. Also, log in to the LS1 PCM to see what temp the computer is seeing. It could be that you have a bad connection on your gauge sending unit.

 

i got confused w/ that issue also. sit there and look at the temperature gauge.
the line before 220 is around 195, and the gauge is not seperated evenly. the first half of the guage is spread out while the second half of the guage is compressed. i was thinking my car was running hot, when it actually was reading correctly, i hooked a scanner on it to find i was running at 195 when the gauge was looking like it was near 220. i run at 220 when in extremely hot weather in traffic, but when i turn on the secondary fan it drops right back to 195..

im also not comfortable with the temp its running at right now, i'm looking to pick up a set of aftermarket fans, anyone have recommendations?