engine wont even come close to 190'

[rraulston]

just bought a used 1999 2500 quad 4x4 auto. The engine does not run up to 190 then drop back down then up ect like my 96 did Beeing that 190 is half of the guage, i run in the middle of 190 and the line to the left. Closer to the left. Sounds like a thermostat to you?? and when its cold, the tach fluctuates a little but the enging seems smooth. Gee, my 96 NEVER had any of this... RRR

 

[RACE427]

thermostat

Thermostats usually last about two years and then start to open at colder than rated temperatures. I would install a new Cummins 190 degree stat and your problem s should cured. Be sure to change the coolant while you are changing the thermostat as you can bet it was never done. Hope this helps, Tony G

 

[BK]

my 99 hardly ever gets up to 190. . If I run it hard I've been able to get it to there... doesnt stay long, comes back down to where yours is... I havent changed the thermostate yet... but it's been that way since day one (bought new)... my tach is just fine.

 

[LSMITH]

It is simply the nature of the beast. You have a 180 degree thermostat in the 99 and it is working fine. If you want it to go higher get a 190 thermostat and put it in. The tach in your 99 is 100% electronic running off of the crankshaft position sensor. They fluctuate a bit and you will notice if you look very closely and operate the pedal very slowly that it is notchy as it rises and falls. This is just the nature of the beast as well. If you have any more questions let us know.

 

[MidwestMotorman]

hit 190???

I do not know how one would hit 190, especially with a heavy duty cooling package like mine. I have only hit 190 once. It was on a 68 degree day, with my leather winter grille cover on, and all the grille vents closed, with 7500 pounds in tow at 60 mph. All hilly country too. My thermostat will fluctuate so I know it is not stuck open.

 

[Cooker]

It all sounds normal to me.

 

[MCummings]

The only way I can get my truck to get to 190* is to run against the rev-limiter in 5th gear for 1-2 minutes. then it holds a solid 190* but as soon as I back off a bit and try cruising at 85-100 it's back down to the 180* or so.



MerrickNJr

 

[speedracer]

By the way, Nathanbush, it's not a good idea to run with the grill opening completely blocked off. You need to allow some air flow to the intercooler.

 

[MidwestMotorman]

intercooler

Speedracer



If I remember right the intercooler sits near the bottom of the radiator. Ther is a 3/4 inch gap below the grille for air and the lower vents in the bumper are not blocked. Those bumper openings allow air to my oil cooler and do let air through the intercooler if I am not mistaken.

 

[Cooker]

illflem has done alot of research reguarding blocking the intercooler (he has an air intake temp gauge). Depending on your outside air temps, you can easily block 100% of the grill (I think the bumper openings do allow air into the intercooler). In the winter illflem runs grill inserts and fanless and sometimes his air intake temps still doesn't get warm enough. Caution is necessary though. No running the AC or running the defrost if you haven't disabled the AC compressor in defrost.

 

[ISBPilot]

T-stat history

I had one of the 99's with the bad batch of thermostats (didn't show up until out of the 36,000 mile warranty). It started heating up when under a load. Replaced it with a 190 degree, around 40,000/16 months old. The last few weeks when I started up in the morning it would run up and spike at about 205, then drop back to 190 and run all day just like normal. Now at 107,000/36 months old. Poped the top and found one side broke loose on top = bad feeling in stomach. Guy at NAPA gave me one for a 5. 9 gas burner . Returned it and 30 minutes later found out they didn't have the right type split O-ring to seal it with. Ran across town at 5:28 to get one from the Dodge place (this time a 180). Installed last night and runs up to 180 and rides there just fine.



Todd

 

[barryg41]

My story is the same as ISBPilot's. But today it started to cycle again. I have the 190 t-stat right now. But I might be looking at the 180 again.



I dont know who said it, but they recommended that changing the t-stat with the coolant might be the trick. Heck it is mt of coolant and three bolts off. You can change out the t-stat. I know, I know, it costs money... .



But it makes your baby run better.

 

[rraulston]

well i changed the4 thermo last nite. you wont believe what i found. Parts of another thermo bouncing around in there. I fished out the parts and put in the new one. Wouldnt you believe it. Arizona is in a cold spell. Got down to 34. Almost shut down the town!!! HAHAHA RRR

 

[BK]

I bought a cummins t-state from Genos in the summer when I orderd a filter kit. Figured it would come with any required gasket, but didnt. I was gonna change it and the antifreeze this fall, but corporate had other plans for me.

So I put it off till the spring. By than if things arent back to normal I probably wont own it anyway...





So if I do do it this spring, what gasket(s) are needed when changing it?



tnx



Bob

 

[barryg41]

If it's the right t-stat..... there is no gasket. Just pull out the old one. Make sure nothing is hanging around in the hole. Make sure nothing is stuck on the gasket seal area. The new t-stat has a kind of built in gasket.



It only adds 5 minutes to the job when you change the coolant!! If it's a 12'ver it might take a little longer taking off the upper altenator bracket to get to the t-stat.



Hope this explains the no gasket thing!

 

[BK]

Thanks Barry, ya mines a 99 like yours.



after reading what you found, I'm now wishing I did it in the fall. But since things got tight and I didnt think anything was broken, figured I'd leave it.



The t-state I got from Geno's is a Cummins. There is a rubber ring around the outside rim of the t-state. . so that explains it.



Thanks

Bob