whtscion04

I just installed a used engine with 80k miles on my 04 Scion xB yesterday. Everything seems to work fine, but the temp light began to blink. The radiator, water pump and thermostat are a month old and were on the old engine.
The temp sensor is brand new. There is no boiling over or anything that is out of the ordinary.

Any help is greatly appreciated.


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MileHightC

Pinched wire or a bad ground somewhere in the temp circuit...where did you get the new temp sensor and might not be a bad idea to invest in a new thermostat as it's a relatively cheap and easy thing to eliminate.

whtscion04

I got the temp sensor from O'Reillys. I will be changing the thermostat this morning.

How can you tell if there's a bad ground?

MileHightC

Bad grounds and pinches are a pain to troubleshoot but you can throw a meter on the circuit as it's running and see if your voltage fluctuates a fair bit...

Do you still have the old motor as I might be inclined to try the sensor off that one...when it comes to sensors and body panels my rule is to always go with OEM parts.

whtscion04

I do have the old motor, but the sensor that was in the old motor broke off lol. That sensor that broke off was also from O'Reilly's. Let me ask you this and maybe you can shed some light on this. Before I switched out the old motor I had a mechanic tell me that I had a blown head gasket. He decided to tell me the price which was more than what the car is worth. He said I can put some blue devil in there to give you some time to save up to change the engine. Well he put that in there and maybe 20 mins into into the water pump goes bad, water is gushing out. He replaces the water pump do you think there is still some blue devil residue in the radiator which is causing the light to turn on? New coolant was used after the used engine was installed.

MileHightC

I hate the 'quick fixes' as they never seem to work and cause way more trouble down the line...Stop-Leaks and Blue Devil, etc. I don't know if any residue would affect the temp sensor circuit but a flush, which sucks because you just added new coolant, couldn't hurt.

I'd still check the temp sensor circuit or replace the sensor itself first...

whtscion04

We installed the new temp sensor and the light is still blinking. The thermostat was also replaced and it's still blinking also. The light only comes on when you drive. Once the heater is turned on the light itself turns off and wont turn back on until it's being driven.

MileHightC

Given that the light turns off when you turn the heater on tells me that it may actually be running hot as that's another way to cool things down. If it only comes on when you drive then it shouldn't be an issue with the e-fan as it's getting air through the radiator. Does your fan turn on when you let the car sit and idle? Have you checked the fluid level in both the coolant reservoir and in the radiator by removing the cap to see what the level in there is...I'd make sure the radiator was full to the neck where the cap goes. Lastly, is it throwing any codes?

whtscion04

yea that fan turns on when the car is parked. The reservoir and radiator are topped off and there are no codes coming up. It's strange I'm thinking it's more of an electrical problem, but then again im not a mechanic lol. So you think it's okay to drive even though the temp light flashes?