Hey Scotty, I started tinkering with diesels approx 8 years ago (I even named my dog Diesel), I started with a Ford 6 liter. I figured if I could tackle its issues, any other diesel I get in the future would be a piece of cake. Since then I went to VW diesels (A lot less issues and easier to work on). Back in March I bought an 06 2.8 Liberty Common Rail Diesel as a fixer upper for towing a small travel trailer. I have fixed all the mechanical issues, no more Christmas lights on the dash but my Temperature gauge goes wonky sometimes. When I first purchased the vehicle, the gauge would only go a quarter of the way (approx 130 F). I automatically assumed it was the Thermostat. I changed the thermostat and took it for a spin and sure enough the gauge is up to the halfway normal mark. Recently though I have noticed that sometimes it takes a long time to get to temperature and when it does, if I stop at a drive thru and idle the gauge will drop back again. I was reading it in real time through my obd connector and when normal, it runs at 78 C (172F), but when idle it drops back to 66 C (150 F). What I find odd is it doesn’t do this all the time, it’s very intermittent. What could be causing this issue? Thanks, -Confused in Canada

Comments (2)
No. 1-2
DieselDog
DieselDog

Yes I do, it's located in the thermostat housing assembly that was replaced (temp sensor wasn't replaced) I also forgot to mention I used a handheld laser temperature gauge and pointed it at the hose before and after the thermostat and the reading was similar to the obd reading 66 degrees C at idle.

Techsus
Techsus

Do you have an Engine Coolant (Water) Temperature Sensor?