Coolant temp

[gmcman]

This is a little different from the others which is why I started a new thread.

Had a CEL for low coolant temp, trigger temp was something like 156 deg. I replaced the thermostat with a dealer part and while the temp is now "warmer", no lights but the gauge on the cluster stays around 2, sometimes 3 marks to the left...mainly 2. I checked the temp with my scan tool and reverified when I swapped my stepper motor since I needed to lift the needles.

Average temp is around 185 deg, it did get to 195 at one point and the needle was about 1 mark to the left of 210, I watch my gauges religiously and the coolant never really gets to 210 and stays there, it did though when it was brand new.

Could this be a bad sensor and does the ECM use a different sensor for the data it sends the scan tool?

If it's from the same sensor then obviously i need a new sensor but the gauge and scan tool are in check.

When it gets to 195 it pretty much stays there, this only happens on warmer days during longer idling periods...which leads me to believe the stat is opening, but is 195 the opening temp?

Could I possibly have a rich mixture? Fuel mileage has gone down slightly but I contribute that to my 5 min warm up times and winter gas...looking at about 20-30 miles difference in tanks.

 

[The_Roadie]

There's only one sensor, and it looks to be bad. Thermostat could also be a poor performer. Rich mixture could be a bad or sluggish O2 sensor, but that should have thrown a code.

 

[gmcman]

Are these O2 sensors (or any)... known to get the mix out of whack and still not throw a code? I don't have an O2 code but they are the stock sensors.

Generally I change them out every 60K but never had a code thrown with this one.

 

[MichEnvoyGuy]

I just replaced my t-stat, coolant sensor and O2 sensor within the past 2 months. Now when I hook up my scantool, my truck stays at 190 degrees almost all of the time.
My oxy sensor wasnt bad, I somehow mashed the wires when I replaced my motor mounts so I had to replace it. I have a 2002 like you so it was probably time.

 

[Harpo]

Mine is steady at 195,8F 91C have been up to 201F 94C occasionally according to the Torque app.

 

[RayVoy]

The temp gauge should read right around 212 f (100 c), which is straight up on the gauge.

You could have a bad sensor, a bad gauge, a new (but faulty) t-stat, or, perhaps the wrong t-stat.

Perhaps you purchased a 195 deg t-stat instead of the higher temp t-stat (maybe 210 deg, I'm not sure).

See is you can borrow a wireless temp reader (the point and read pistol style), at least the actual temperature will be answered.

 

[Harpo]

The temp gauge should read right around 212 f (100 c), which is straight up on the gauge.

You could have a bad sensor, a bad gauge, a new (but faulty) t-stat, or, perhaps the wrong t-stat.

Perhaps you purchased a 195 deg t-stat instead of the higher temp t-stat (maybe 210 deg, I'm not sure).

See is you can borrow a wireless temp reader (the point and read pistol style), at least the actual temperature will be answered.

On my part i bought a OEM T-stat and it was marked 90C 195F if i remember it right.

 

[djthumper]

I would check the part number of the thermostat that you bought. It sounds like you got a 160 degree thermostat instead of the 192 degree. I would not totally rule out the temp sensor at this point either.

 

[MichEnvoyGuy]

Now you guys got me thinking. I bought my the Stant t-stat and I dont remember the temperature of it but my scan tool reaches 190 degrees and thats about it. Hope I didnt buy the wrong one because with all of the trouble I had last time I DONT want to do that job again for a long time!

 

[Harpo]

I would check the part number of the thermostat that you bought. It sounds like you got a 160 degree thermostat instead of the 192 degree. I would not totally rule out the temp sensor at this point either.

Lets see 192F is about 88C,,,I got the right one, i have to check my temp sensor then.
I have a IR-tempgauge at work that i can borrow to check the actual temp, cant get to it until next week unfortunately.

Sorry for

 

[gmcman]

I know I have the 195 because it will stay at around 185 but when it climbs to 195 that's where it stops. At least I assume that's the correct one.

Temps wouldn't get above 165 before the change. I may change the sensor first hoping to avoid the labor of the stat.