Never before have I dealt with a engine running too cold, it's a strange feeling to look at a temp gauge and wishing it was reading 50 degrees higher.. Anyways, I went for a drive this evening and logged the coolant temps and during the entire 30 minute drive the temp never went over 130 degrees.. I verified my sending unit is working properly and the temp is accurate, It's not reading improperly I am 100% sure of it.

I then had a theory and went home and put in a big piece of cardboard that covered half of the front of the radiator and went for another 30 minute drive, Temps were consistently @ 175 degrees.. Just by blocking the front of the radiator my temps went up almost 50 degrees and stayed there... Then to prove the radiator carbboard block actually made a difference I removed the cardboard right away and went for another drive and the temps never went over 130 degrees... The ONLY time my truck will reach 175/180 without the card-board block is if I let it idle in the driveway for 15 minutes... While idling it will slowly work up to 185 and the fans will come on and temp will drop to 175 and stay there... Then when it's at 175/180 I immediately jump in the truck, go for a quick ride and the temps will almost instantly drop back own to 130..

My radiator is not a LS swap radiator, It's a standard sbc/bbc style replacement aluminum 4 core high flow radiator that fills the entire front of the grill and my LS1 is 100% stock including the water pump.. right now I have the upper radiator hose going to the inlet by the water pump pulley and I have the lower hose going to the thermostat block on the motor. Also, My fans never come while I drive it because I have them set @ 190 and it doesn't ever get that warm. My thermostat is a 180, So what do you guys think is going on here? Do you think it's a thermostat issue? I just don't understand how my temps are nearly perfect if I block half the radiator from air flow and then without blocking the radiator at all the temps drop to 130 while driving it. Any advice let me know, I'm sure 130 degrees is not good on engine parts so I want to get it fixed soon. Thanks guys!

 

First check temps with an IR thermometer.
Second, replace the thermostat.
Third, any chance you hooked up the cooling system with a surge tank? I've seen setups with surge tanks incorrectly plumbed to bypass the thermostat.

 

My 98 Camaro has run about 130-150 since new unless I am sitting in traffic where it will get warm enough for the fans to come on. I thought it was an issue when I bought the car but I was told by the dealer that the LS1 runs better at cooler temps. I now have over 150k on the car and it has never been an issue. The heat has always been hot as well. If you have hot heat I would not be concerned with it.

 

You have water circulating through the radiator when the engine is cold. Your thermostat is either bad or like said above you are byassing it somehow.

You can test the thermostat in a pot of water on the stove. Use a kitchen thermometer to see what temp it opens.

 

The 4 core radiator is def a little overkill for a LS motor. IMO

 

Maybe put a hotter T-stat in ? (won't open until hotter) But ,yes, sounds like it's stuck open ?

 

Yes, I did verify with a IR thermo the temps are correct. I will post a pic of my engine bay when I get home tonight to see if something jumps out at any of you. I did purchase a new thermostat when I put the truck together 2 months ago. Thanks for the suggestions so far


nathan

 

I've seen new parts right out of the box that were faulty, don't assume just because you "purchase a new thermostat when I put the truck together 2 months ago" doesn't mean it couldn't be an issue. It's too easy to take it out and test it as Pop N Wood suggested to eliminate a possible cause of your problem. JMO