mbw

Does anyone know if there is a 160* t-stat available for a 99 Dodge diesel. I have tried all my local parts stores and all I can find is a 180*. I had the chip boosted and when under heavy load the truck has a tendency to run hot (220*) during the summer months, and I can't use A|C without it red lining at 240*. I have cleaned the outside of the radiator and trans cooler, but haven't had a coolant flush yet. All hoses look and feel good, so I don't think any are collapsing and I have replaced the air filter. Would the 180* be enough, if I can't find a 160*? Also my other question is on the cycling, I have read other people saying that their t-stat cyclings enough so that you can see it on the gauge, I bought my truck new and have never seen this, is this common to all 99's ?<br><br>

bulabula

I'll take a stab. I bet a Cummins Power Store would have a 160 t-stat. Engine heat is a good thing most of the time; but I would think a 160 is too cool.<br><br>I've only got an '03, and I haven't noticed any fluctuations in engine temp, nor would I expect too. But I've read here where that indeed happens with CTD's. The ONLY times I've ever seen the temp guage fluctuate, it was due to a faulty thermostat. If a thermostat opens and closes violently enough (ala spring open and closed) to where the readings bounce, it's not performing right. Its function in life is to maintain a steady-state temperature condition.<br><br>Not knowing how many miles on the coolant or installed thermostat, my first thought would be to replace the thermostat with a standard factory temp t-stat, or possibly a 180 to see how it performs.<br><br>I normally like to drill a small hole in the thermostat to help prevent an air-bound condition.

BigBlue

I went checking for a 180* T-stat for my 01. I called up Cummins and they said that they would not sell me one for my truck. 160* is way to cold. 180* would be the lowest I ever go.

emjay

A lower temperature thermostat will not cure overheating problems. You might want to check your fan clutch. You should be able to hear an increase in fan noise when pulling a grade with a load. Another quick check is when the overheating occurs, pull over, stop the engine, open the hood, and try to spin the fan by hand. It should be difficult to turn. If you can turn it easily or it spins freely, it is your fan clutch that is the problem.

mbw

73K miles with original t-stat and coolant. Scheduled for a system flush next week. <br><br>Will check the clutch fan too. <br><br>Thanks a bunch. <br><br>Molly<br>

sidekick

mbw, <br>the t-stat does not control engine overheating a t-stat<br>only maintains a minimum constant engine operating temp. A 160 t-stat is definitly a no-no. Your engine fan should ROAR at anything approaching 220 degrees. I believe the fan is the problem although the flush and refill is due and won't hurt a thing. Post an update with the results.

mbw

I know what a clutch fan sounds like, I have one in a GTO, but to be honest, I don't think I will hear it roar over the famous diesel rattle. I will however be pulling my camper Memorial Weekend, I will put on the AC and see what happens. I will forget the 160* t-stat in the meantime.<br>I will post my discovery. <br><br>Thanks everyone!

DarrellB

If I was a betting man (and I sometimes am) I would say your T-stat is stuck closed right now. I can run all day with the PM 2 on kill with 100hp injectors in 90* + heat and mine will never go over 190* with a 180* T-stat. Take the old T-stat out and replace it with a new one from Cummins. I'm willing to say this might solve you problem. If that doesn't then the fan clutch is shot. <br><br>Good Luck<br><br>DB