Temperatures fluctuating

[caninecop]

Temps showing on the Scangaufe D were fluctuating, going to a high of 200 down to 188 on the road. Not sure if it’s the thermostats doing what they are supposed to do or if there is a problem with one of the 2 thermostats.

Temperature at the time was 85 and on a straight road with no hills. I don’t think it is the radiator, I just cleaned it and the CAC. With the motor running I get great air flow through the radiator when standing behind the radiator.

[CountryB]

Possibly the engine temp got up to 200 then the hydraulic fan (if you have one, I'm not sure what engine you have) went to high speed and pulled the temps back down to 188.

[firedoc]

I routinely watched my temp go to 200 and back down to 185 and then back up and back down infinity. Then I had my cooling system flushed and new hoses and belts placed. Only because I thought it was time after 14 years[emoji33]. They found both thermostats broken. Replaced with 190 thermostats and now runs pretty consistently at 190. Have to find something else to watch.

[caninecop]

Originally Posted by firedoc

I routinely watched my temp go to 200 and back down to 185 and then back up and back down infinity. Then I had my cooling system flushed and new hoses and belts placed. Only because I thought it was time after 14 years[emoji33]. They found both thermostats broken. Replaced with 190 thermostats and now runs pretty consistently at 190. Have to find something else to watch.

Thanks for the post, the engine was rebuilt 3 years ago and the thermostats was one of the parts that were replaced. I know that parts can go at anytime, I will have freightliner check them and replaced if needed.