Coolant temperature

[RSCTRANS]

OK, here goes – I just started driving my 2010 international lone star a week and a half ago. I have steadily been doing preventive maintenance on this truck since I joined this form and have learned so much. I noticed when I started driving this truck that the temperature would remain around 205° weather I was loaded or not on on flat ground or not. But now, I am scratching my head. Here is why – yesterday I decided to stop in Georgia and replace all of the relays. ( I did all of the fuses last week). After I started driving again, after replacing the relays, my temperature went down to normal. I have since picked up a load this morning and I am traveling up interstate 81 and the temperature is still staying normal, with some increase when pulling the hills. Is this a coincidence? Or could changing the relays actually have something to do with the temperature?

[RSCTRANS]

I forgot to mention that it is cm870

[Waterloo]

A 2010? Should be a CM-871... Duh, I saw your looking at coolant... Oil should be running just a tad over 200 degrees. Water should, under normal conditions, be running around 180-185.

And owning a ProStar, replacing fuses and relays will do some odd things... But I doubt they would physically change your operating temps. I don't recall a relay for the dash cluster or gauges, maybe there was a resistance issue somewhere and the new fuses relays solved that. I don't know, these new trucks are a real adventure, and rarely a good one.

[RSCTRANS]

Thanks Waterloo. I agree with you on the experience. It has become less frustrating since I found this forum. I am learning tons of information trying to take it in as fast as I can as I have five trucks. Four with Cummins.

[Waterloo]

One thing too, have you changed the coolant filter? It is located on the frame rail up on the passenger side near the bottom coolant line. That could cause you some real headaches if it is clogged. many guys do not know there is a filter there and never change the damn thing. I forget the part number, but we use the straight filter, non additive one. TA normally carries them.

[Nilao]

If the thermostat has never been replaced I would do that. At 600k miles mine had groves cut into the metal and was sticking. I plan on making that a 500k mile item to replace.

[Waterloo]

Yep, thermostat! And if it were me, I would drain the coolant and put all fresh in, replace the thermostat and coolant filter. If able, I would flush the system too... Quick serve has the procedure.