Engine/Transmission (1998.5 - 2002) 2002 HO Thermostat problems?

[CAPTPHIL]

Your original thermostat could have been sticking, also summer temps. It could be nerves with new truck.
Good Luck CAPTPHIL

 

[Bunyan]

Ok cool. Is there a reason why I have never noticed this in the 2 months I have owned this truck? Maybe I am just being overly concerned! Thanks for the help.

I had the same problem with my 01. When towing heavy it was even worse. When towing heavy long grades the engine would also have a rattle. Mopar issued a TSB for this # 09-008-02 which called for a special replacement thermostat. Mopar# 05015708-AC or Cummins# 3946849. The replacement thermostat looks like a hockey puck. This corrected the cooling and rattle problem. The truck does not get over 190 at anytime. I live in central Tx and it gets hot. I've towed backhoes in August and the problem has not occured since the above repair.



You can read about this TSB at TSB 09-008-02



The cheapest place I've found to buy this replacement thermostat is Pollard Mopar @ Pollard Mopar Parts - Genuine Parts and Accessories $67. 18 w/ shipping and handling.



Any other Dodge dealership wants $96. 00. The local Cummins dealer wanted $78. 00 for part only.



(Also when replacing the coolant, DO NOT HAVE ENGINE RUNNING WHILE FILLING WITH NEW COOLANT AND WATER! There is a baffle that will close and create a air pocket inside the block. ONLY FILL WHEN TRUCK IS OFF!) This info is in the service manual.

 

[upsyes]

Just returned from a long trip to yellowstone etc... and your gauge is reading completely normal. I replaced my thermostat with a genuine Cummins thermostat as a precaution and consistently had the same readings as yours no matter whath the grade or outside temp.



If your Fan Clutch, Thermostat, Radiator, Water Pump, Coolant and associated parts are all known functional then your readings should be as shown above. It can get a tad higher but not by much.



I was towing a 6500gvw travel trailer with bikes mounted up front and the bed full of junk and I never topped the readings shown by "twheat" above

 

[Turboman]

sounds normal to me for a 190 tstat, If your interested in a 180 I found a Cummins #4929642 that is a wide mouth or large hole tstat, it will also fit a 6. 7 I think.

 

[upsyes]

no need

I would NOT change your thermostat to a lower than OEM degree thermostat. Your Dodge is computer controlled and relies on the temps to be at a certain range for everything to work together in harmony. Also a diesel is way more efficient at higher temps than lower ones.



Check out this website to learn everything you ever wanted to know about cooling systems and how and why they work the way they do. Some day I will change over to Evans NPG+.



NPG+ » Engine Cooling Systems



CLICK ON THE "HOW IT WORKS" LINK AT THE TOP OF THE EVANS' PAGE!

 

[twheat]

UPDATE: Looks like I have a faulty temperature sensor. Here is the reason why I say that. I decided to grab my digital laser temp sensor to see what the temp reading was at the temp sensor housing right next to thermostat. After reading on this site and others these motors take a long time fully warm up due to their size and capacity of fluids they hold. I have noticed it takes my motor according to temp gauge about 8-10 minutes to reach the 190 degree mark driving on 25-35mph side streets which after reading seems really quick. So today I grabbed my digital laser temp gauge and ran the truck until the temp gauge hit 190 and started to creep like it does into the 200 degree zone. Today when it started to do that the digital laser temp gauge said right around 120 degrees. As I drove around more I hit between 140-160 and had to stop due to lack of time. So if my gauge in my truck is moving past the 190 degree mark but my digital temp sensor is reading around 140-160 it seems to me the sending unit for the water temp gauge is bad. What do you guys think?

 

[Sticks]

Presuming your thermometer is accurate, and you were taking readings right at the sensor mount, then yes. I'd be checking the upper radiator hose at the radiator as well. Air blowing on metal will cool it (engine fan), whereas the inside will be hotter.

 

[mhenon]

twheat, PUT THE LASER GUN DOWN AND BACK AWAY FROM THE ENGINE!!!

Seriously... you're fine. Those readings are perfectly normal. Given your location you could run that rig without a fan, thermostat or temp gauge and never have a problem. With a new fan clutch you'll know when things are getting too hot.

Mike

 

[twheat]

twheat, PUT THE LASER GUN DOWN AND BACK AWAY FROM THE ENGINE!!!

Seriously... you're fine. Those readings are perfectly normal. Given your location you could run that rig without a fan, thermostat or temp gauge and never have a problem. With a new fan clutch you'll know when things are getting too hot.

Mike

I knew I'm fine, the gauge is acting up so I am just trying to correct the problem. I understood with a new thermostat and fan clutch I am good. I am just seeing some really weird readings on the gauge from the inside of the truck that's all. Like I said its a new truck to me so I am just trying to learn as much as I can and make sure it is running properly. Thanks for the help guys.

 

[CAPTPHIL]

Trust us,
I have over one million miles exp. pulling boats to the four corners of the U. S. and Can. , with two 2nd Gen 24-valve 3500`s.
YOUR TEMP. GAUGE IS NORMAL Enjoy your truck and drive it like you stole it. And keep it serviced.
Good Luck Capt Phil