Drove my 06 LR3 2 miles to a local lunch joint the other day, cold and windy, truck had hit operating temp but just barely. Went in, returned 20 minutes later, truck went into it's cold start mode RPMs 1200, fan on high, temp gauge pegged on the floor - like the key was off (odd).

After the typical warm up time, it never returned to normal idle, fan stayed on high, and temp gauge never moved off the floor. THERE WAS NO CEL.

Drove it 2 miles back home, felt like it had no power, stumbling, idled high, fan stayed on high. Right as I was turning into my neighborhood - temp gauge finally started moving and the truck began running better.

After turning truck off for 10 minutes, cranked it up, everything normal. pulled a p0116 code.

Does this sound like a typical Engine Coolant Temp sensor symptom? Most OBD explanations for P0116 say it should have triggered a CEL.

Regardless, if I'm going to replace the ECT should I just go the extra step and replace the entire t-stat housing since I'll have the TB off? Truck has 75K miles on it.

Thanks,
/Clint

 

It should have triggered a CEL so that by itself is weird...

I would replace the coolant sensor AND the thermostat. Thermostat isn't that expensive and is not hard to replace. My guess is the sensor is inop and since the t stat is set up to fail open, the computer may default to running the motor cooler to be on the safe side if the sensor stops sending data.

 

Thanks for the reply. Can the sensor be replaced w/o removing the throttle-body? Or is it recommended to just to remove the TB and do the entire t-stat housing, which includes the t-stat and sensor? From a mileage perspective I think mine is a little early for the entire housing, but maybe it makes sense to just replace it anyway.

 

Good question.

If you're only replacing the t-stat, not the full housing, you can get away without removing the throttle body.

For the whole thing, you can unbolt the throttle body housing and leave it over to one side still connected to the coolant hoses. No real need to replace the housing entirely unless you see signs of cracking or leaking. Once they start you'll want to address that.

But it looks like since the whole housing comes with both the t stat and temp sensor it may be easier to do the whole kit.