I realize there aren't a lot of guys on here with gen 3 3SGTE's but maybe you guys can throw out some ideas for me! So ever since I did my gen 3 swap in my ST165 I have had a problem with the engine not warming up all the way. It has only gotten worse since I installed a Mishimoto rad. I can let the car idle until the fans come on and it gets up to operating temp (takes at LEAST 15 min) but as soon as I start driving and get air going through the rad the temp drops like a rock. So bad that my heater has barely any heat coming out of it...Could my T-Stat be stuck open/shut? what is the opening temp of the stock 205 t-stat? I know KO racing has one that opens at 160F but I would definetely like a hotter one if possible!
It has to be your thermostat, it does not matter what gen the engine is the cooling system has to be the most basic system in the car. Some hoses, a radiator and fan, some temperature sensors, an engine block with cooling passages, a water pump and a thermostat. The ONLY thing that controls the temperature of the engine is the thermostat and it is a very basic mechanical device with a valve, a spring, a wax pellet and a piston. when the wax pellet heats up it expands forcing the piston to open the valve allowing coolant from the radiator to flow into the engine. When the engine cools down enough the wax cools down and shrinks allowing the spring to close the valve in the thermostat. Since your having a heating problem, not a cooling problem we can do away with the radiator and fans and sensors and water pump and hoses. We don't need to pump coolant, or cool coolant, and the sensors are just for pollution control and fan control. So were just left with the block and the thermostat. We could plug the 2 coolant connections and the engine would run until it got to hot. Since that's not happening, you must have a constant flow of coolant going through the engine soooooooooooo.......... Your thermostat has to be stuck at least partially open either through mechanical failure or because the thermostat housing is becoming heat soaked and giving the thermostat a false high reading.
Thanks for the reply. Unfortunately that motor cracked 2 pistons and is in the process of being replaced. When I pulled the thermostat everything looked normal on it but I'm not sure if it would look any different.
If its failed totally it would be in the open position but if its just a weak spring you need to test the thermostat with a pot of water and a thermometer on the stove and it will tell you what temp the thermostat opens at, that's really the only way to test them.
make it easy on yourself en change the thermostat, probably a bad spring on this one keeping it open all the time. Thermostats only costs a few bucks. At least you know it won't overheat very fast
I've had the temperature slider fail on my heater control (cracked solder joints on the circuit board). This was preventing any heat to come out of my ventilation system. You can validate your heater control is functional or not by checking the mechanical valve operation in the engine bay. It is located on the driver side, just beside the firewall, not so far from the diagnostic connector. It is a small box allowing coolant to pass into the heater lines, with a small lever on top, operated by a steel wire coming from the cabin. If I remember correctly, I believe the lever is closer to the firewall when heat is slider is set to hot, and towards the front when set at coldest position. It can be checked easily without dismantling anything, helping to rule out any heater control malfunction. Also, head lift under boost+high rpm or failed head gasket can also allow combustion gasses to enter the cooling system, creating air pockets, hot spots, and erratic heater operation (bubbles in the cooling system tend to stick around the heater circuit).
