Thanks for looking
I have APS TT with built short block. My car was running fine till yesterday. It has about 20k miles boosted.

Here is what happened.

Cold start. The engine temp goes upto "H", but water temp (sensor located right before the upper radiator hose) was between 140F (60C) and 158F (70c). Oil temp (Sensor located before oil filter using sandwich plate) was near 86F(30c) tp 104F(40c). Radiator fan is on after the stock engine temp goes above 9 o'clock position. Heater is working fine. Radiotor fluid is full. Oil and all other things seems ok. There was no leak from radiator too.

Once thermostat opens up, the engine temp on stock gauge is at 9 oclock position and the defi water temp is at 90c. so basically it returns to normal. It taeks up to 10 minutes, from "H" on stock gauges to return to 9 oclock position.

Is it gonna be my thermostat goes bad, or engine temp sensor?

Where is stock engine temp sensor located?

Thank you for your help guys

 

most likelly thermostat but no way to tell for sure without knowing true temp.

 

You most likely have air in the cooling system and the factory sensor was reading so high because of an air pocket around the sensor.

Throughly bleed the cooling system and this should fix your problem.

-George

 

+1

 

yeah they are most likely right

 

+1 on the other advice.

If the thermostat is bad, when the temp spikes on the car turn the heat on, if it blows cold air then the thermostat is bad.

 

could also blow cold air at idle due to a air pocket. they are stupid hard to get out of these cars.

 

Correct, these cars are a PITA to bleed properly.

I am 99% sure the OP has an air pocket, I wouldn't worry about it - just bleed it as soon as you can.

-George

 

Can you please elaborate or show where you have posted before on the "proper" way to bleed? Not being a smart ***...but I have been through the ringer with this "bleeding" crap.

I would really like your version...

 

Jarrad, George, Vash350z, Cass007, Red Rider, Thanks for your replies.

I will try to bleed coolant first, but that's pain in axx.

One thing I don't know is that my car was running perfect for 20k after I put turbo. Hmmmm. How did air get into the coolant system?

 

do you really want that answer?

 

Headlift maybe.

 

I know I wouldn't

 

^ +1

 

exactly what I was thinking...I don't know why after 20k of boosting with no issues, all of a sudden he needs to bleed his system, unless its the dreaded you know what

 

Who built the OP's short block? Is it sleeved?

 

 

not to thread jack... but I just got done with my build and I think I have a little air in my heater hose/core. every once in a while when the car is hot it bubbles in my heater hoses.

so what about bleeding the system?