Thread: Direction of coolant flow in v8

My 3.9 Rangie with Thor manifold recorded 82C on a thermocouple placed in a head thread next to the thermostat.
Seeing the Thermostat is supposed to open at 88C , I do not know whether the thermostat is wrongly marked or the thermocouple is inaccurate.
If there is an 88c or 92c Thermostat in the system, it generally should run around that , or am I missing something???
In any case if it is really running at 115C. if a V8 runs over 100c you will soon have problems with moving sleeves. I think you have a problem.
Regards Philip A

My 3.5 with edelbrock manifold and an autometer gauge sender in place of the original one runs at around 88 degrees mostly. Stuck in traffic with the aircon on full on a 35 degree plus day and it maybe and very rarely gets to 92. I would have thought anything over 95 was too hot.

Ian

I agree that 88 deg C is the proper temperature for the thermostat to open. I guess the temperature reading will be different, depending on where the sender is located. Another thing too is to make sure that any sender or guage is actually reading correctly. Best to have them calibrated against a known accurate one.

The marked temperature on a thermostat is the temperature at which it is fully open. They actually start to open a good bit lower. The boiling point of your radiator water is governed by the pressure. With a 15psi cap the boiling point is 250 f./ 121 c. Stuee say he is registering 107 with the a/c on, so he has a pretty big margin before the jigger tea-kettles and blows all its water out.

My 84 RR has the thermostat at the outlet from the head, whereas the D2 has the thermostat on the inlet to the pump, but with about the same opening temp, so the D2 is going to be hotter at the head outlet.

Well at least I know the sensor is roughly in the right place (factory sensor still there but that things useless). Guess to be on the safe side its time to get a radiator flush and service. Guess theres no beach fishing for me anytime soon