I have a quick question, i used the search bar and all i could find were threads about how its normal for a coolant temp gauges to fluctuate, but my problem is that my thermostat appears not to be fluctuating at all once it reaches operating temp. It runs around 180*, or 3/4 of the way to the 190* mark, i dont understand if its the thermostat, or a dead giveaway for something else, my water pump was leaking a miniscule amount of coolant when looked under the hood, and by miniscule i mean enough for the block to look a little wet in the area underneath the pump, my rad hose is hard and hot when the truck is up to temp and there are no signs of a head gasket leak.
I read somewhere that in 98' they replaced the fluctuating gauge with an "idiot gauge" because of the complaints.
Looking into the pump..But i just wanted to share and figure it out before i start throwing the cash
Thoughts?
it will fluctuate barely and when it does the needle barely moves an 8th of an inch. Its usually when i drive on the highway. Would it be worth it to buy a new cummins oem thermostat just to see?
Not trying to highjack here but I have the same issue, mine always seems to climb 3/4 of the way then hang out there all day. And every now and then it will spike up or down and bounce around for a bit then back to the 3/4 ish mark. Im guessing that means a thermostat is needed?
Would you guys recommend a cummins one or any replacement?
Again, you don't have a problem. They're not *supposed* to fluctuate. The large cooling system can sometimes cause it. I forget exactly which it is, but I know there is a thermostat available that stops the fluctuation and keeps the engine at a constant temp.
Mine fluctuates when the air is cool. I doesn't fluctuate when it is hot. Normal temp on my gauge is about halfway between the 140 and 190 marks. It was the same when the truck was brand new. If your t-stat was stuck open the temp would never come up and if it was stuck closed the engine would overheat. Leave it be.
One more thing. I've replaced my share of t-stats, always with Cummins parts. One didn't fluctuate, but I never considered it to be faulty or special.
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