Last year I pulled the engine on my 82 to install a cam, aluminum heads ect. and ever since the temperature gauge is constantly fluctuating between 180 and 210. Stat is a high flow 195. Everything is new, radiator, heater core, water pump ect. At first I thought I had air in the system but after many drives and miles it still does the same thing. The one thing I did not change because it was fairly new was the temp sender so today I bought a new one but have not installed it yet. Could this be my culprit? It did not do this until these changes were made. Also I had a 180 deg stat in before the 195 and same thing....

 

No ideas anyone??

 

You left out some information.

Regardless if you have driven it a hundred times....IF the hose from your coolant overflow reservoir is not correct...there is no way of knowing if the coolant system is actually drawing in coolant mix from the RESERVOIR when it is cooling down. I have filled coolant system when dry...got the thermostat to open and filled it and capped it off and took it fora good drive and got it hot and under pressure. Then I filled up the overflow reservoir with coolant mix....and when I would come in the next day...the reservoir would be almost sucked dry. This us why I now drill a very small hole in the thermostat so it can allow the air that is in the cylinder heads to get out. And this small hole does not effect the cooling of the engine at all.

IS the radiator cap good???? has it been tested????

Have you pressure tested your coolant system????

ALSO...your temperature sender. You have to verify that it is GROUNDED to the head. SO...if thread tape or sealant was applied to it...OTHER THAN the sealant that is factory applied which has metal particles in it to aid in a good ground....You can have an issue there.

I do not know if I would put in a high flow thermostat.

DUB

 

What Dub sez about the reservoir, and keep it at the HOT level. After she cools off, open the rad cap and make sure its full. Repeat process

 

The rad cap has not been tested neither has the cooling system. The new sender has what looks like teflon tape around the threads. Have not installed it as of yet. And I think when I was installing the one that's in there now I used teflon tape as well. It said to use some for aluminum heads in the Edelbrock instructions.

Thanks for responding DUB.

The stat I am using is a Robert Shaw which I think has the hole in it and my reservoir is at the hot mark after driving.

 

Test the cap...if it holds 15 psi...your GOOD....then test the system and make sure they hold 15 psi for about 15 minutes.

The hose from the radiator to your coolant overflow reservoir is IMPORTANT....the clamps and hose MUST be in good condition so the system will operate as designed. Loose or leaking clamps and a pin hole in the hose will NOT allow the system not work as designed.

DUB

 

Ok will do but how do you test the cap?

 

A 190 stat floating between 190-210 isn't that far out of the norm. I would try a different thermostat and see if the reading is better. You may just have a sticky stat that's hanging up a little.

 

The tool that is used to pressurize the coolant system to make sure it is sealed up....will offer an attachment that goes on this same tool to test a radiator cap.

DUB