Ok so today I finally wanted to tackle putting in a new temp sending unit after replacing it I hopped in and realized the needle is going up to 260 without the engine even running and when I did start it the just maxed out. with that being said I went to napa and bought another one and switched it this time the needle stayed where it should be but with my obd2 scanner and live data the scanner says the coolant temperature after a 10 minute drive is 201 degress and the gauge says it is around 220. so which do I belive and what do I do about it?

 

Two different temperature sensors in 2 different locations. Could be different temperatures because of where they are. One is on the back of the block (I'm pretty sure) and one is on the thermostat housing.

 

One a sender ones a sensor. Back of cyl head does gauge.

 

As stated, the rear sensor is for your temperature gauge. Also, and it's a common problem, non-OEM sensors run hot. The one i got from Napa rana good 30 degrees too hot, and I replaced it with a Mopar. It's closer to correct now.

 

sorry my bad, didn't know that. I'll remember for next time.

 

Yeah I'm going to order one from Mopar today then see what happens when it gets here thanks guys

 

Only on certain years.

 

yeah. 1997-2001 only have one on the thermostat housing.

 

Ok update mopar sender came today seems to be doing the right thing thanks everyone