CAR - AE86
MOTOR - 7age, bigport head, mild cams, itb's, running adaptronic, only run 350kms since rebuild
USE - Street
PROBLEM/QUESTION -

I've got a fresh 7age that I'm running in, it has a Koyorad race alloy radiator. The water pump setup is a RWD 4AC rear housing with a FWD 4age front cover.There is a fitting in the top of the housing with a hose that goes to the FWD 4age top water outlet as a bypass. The engine is running on water only at the moment as it had a brand new head gasket.

I was using a aftermarket thermostat (Stant I think) that was rated at 180F (~82C) and the car would get up to around 90ish in traffic but drop below 60 on open roads.

I took the thermostat out and put in a genuine RWD 4AC Toyota thermostat rated at 82C. Now the car is running at 90-95ish on open roads and when travelling at low speeds (less than 25) will get up to nearly 100. When I turn the heater on it will drop a few degrees

The thermofan kicks in at 88 so is running most of the time. It never had any issues keeping my old 4age cool on the stock radiator.


I have since tested the first thermostat on the stove and it opens and closes around 82 as expected.


Does anyone have any idea what could be happening? Why the first thermostat ran so cold and the new one so hot.



Cheers