I have a fairly fresh Big Block 496 (built by Lawrence Racing - 660hp/650tq) that is giving me temp spikes right when the thermostat opens.. I didnt have this problem last year however I did have to replace the intake gasket last winter when I pulled off the carb and noticed the intake gasket was squished out into the end ports so I replaced it (I assume it was originally over tightened).. Ever since then when the thermostat first opens the temperature begins to rise quickly until it reaches 220-240 and then it drops back down to 180 and stays there.. It only spies for a few seconds) and it only happens when I initially drive the car and the thermostat first opens, thereafter it will stay at 180.. Other than that, the motor runs perfect! Here is what I have tried so far
1. Pressure checked the coolant system and it held 16lbs for 24 hours.
2. Jacked front of car up, installed a tall funnel and filled it 1/2 way with coolant, fired the car up and left it there until the thermostat opened and until it completely cooled down again. I did this 3 times..
3. Installed 3 different thermostats (the last one I installed is now a 160 so the temp spike isnt as extreme when the Tstat opens)
4. Installed 2 different radiator caps (it never spits any fluid out the overflow into my catch can)
5. Tried drilling two 1/8" holes in my thermostat and it still did it so i put another new thermostat in..
5. Verified there is no coolant in the oil and no oil in the coolant.
6. My radiator never leaks and it never pushes coolant out the over flow
7. My temp gauge is a mechanical gauge located in the intake next to the thermostat housing
8. The bypass hose that goes from the intake to the water pump is installed and was installed last year too..
9. None of my hoses are colapsed.
I know i tried other things, just cat think of them at the moment.
As mentioned, I didnt not have this problem at all last year..
Any help is appreciated
1. Pressure checked the coolant system and it held 16lbs for 24 hours.
2. Jacked front of car up, installed a tall funnel and filled it 1/2 way with coolant, fired the car up and left it there until the thermostat opened and until it completely cooled down again. I did this 3 times..
3. Installed 3 different thermostats (the last one I installed is now a 160 so the temp spike isnt as extreme when the Tstat opens)
4. Installed 2 different radiator caps (it never spits any fluid out the overflow into my catch can)
5. Tried drilling two 1/8" holes in my thermostat and it still did it so i put another new thermostat in..
5. Verified there is no coolant in the oil and no oil in the coolant.
6. My radiator never leaks and it never pushes coolant out the over flow
7. My temp gauge is a mechanical gauge located in the intake next to the thermostat housing
8. The bypass hose that goes from the intake to the water pump is installed and was installed last year too..
9. None of my hoses are colapsed.
I know i tried other things, just cat think of them at the moment.
As mentioned, I didnt not have this problem at all last year..
Any help is appreciated