Hello all ,
I have a question I'm hoping someone might be able to answer.. I recently bought a 1999 s10 pickup 2.2
The check engine light is on so I had it scanned and it says Insufficient Coolant temp. My temp guage in the truck only reads about 150 degrees and never goes above 160 no matter how much or long I drive. I checked my fluid level and it is fine. Everything I'm reading is saying a stuck open thermostat. So I bought a new thermostat (195 degrees) and my friend put it in and I still have the same results. Temperature is still only around 150-160 . now my question is could the thermostat he put in possibly be not seated properly and give the same effect? Because I noticed when he unbolted the housing the old thermostat was kinda loose/wobbly and when he installed the new one it also looked to sit in kinda loose/wobbly.. Im mainly worried about this issue because my gas mileage is suffering and I've been told with the low Coolant temp is a likely cause.... Thanks in advanced.

 

Possibly or the sensor could also be bad I'd check into both

 

Ok I'll check that next. Thanks for the reply.

This is kind of random but I took a digital thermometer and checked the temp of the Coolant in my reservoir tank after a good drive and it was reading 90°F and then I checked the Coolant temp in the radiator and it was reading 148°F I didn't know if the two should be that far off or not or if that's a normal thing . I just thought I'd add that if it helps any

 

The temperature in the reservoir will not be close unless the radiator pressure exceeds the pound # pressure stamped on top of the radiator cap, then it pushes coolant from the radiator into the coolant recovery tank, that's the way it was designed to work.
Take you old thermostat and make sure it's closed, put in in a pan of water on the stove and boil it, while you can put your gauge in there also and see what temperature it opens. Be sure and tie a piece of wire to it so you can pull it out of the boiling water and see when it opens. The temperature is also stamped on the thermostat. This wont cost you any $$ to see how it should work. Good luck,
David g.

 

I know this is a diff prob I got intirally but my choke light stays on in my 1984 s10 durango pickup but when I jus barrally tap the gas it idalls down so I know my choke is working good but I also know it's missing some parts off the carburetor can't complain bout it tho it been a Damn good lil truck pulled some heavy loads with it have put a lil money into her to jus some things I got a deal on