Tstat bad????

[KDillard]

Ok so its getting colder out at nights and the truck has a reall issue at getting up to operating temps and staying there. I have an edge juice and I watch it climb to 180 degrees and then drop off to 158-165 depending on how cold it is. This is happening alot more noticeably in 25-45 degree weather. I drive 10 miles on the highway at 55mph and about 5 around town to get to work. Tonight on the way home it was 35 outside and truck never made it over 170. Talked to the tech at the dealership and he sad the tstat may be sticking slightly causing the motor to not regulate temps. :{ I dont know at what temp the computer needs to give full fueling. I mean driving 30 minutes at 160 degrees cant be optimum for the combustion of the fuel. Any thoughts at this? I mean its not like I am living in extreme temps here in MD. Average overnight temps dont get below 20 degrees.

 

[nickleinonen]

if i don't have my truck plugged in, when the temps are below freezing, my truck doesn't get up to operating temps very quick at all. if it gets really cold [-20°C] my temp gauge will not move during my drive home from work and i don't get heat in the cab until i am about 5 min from home [±30 min drive home from work]

i now have a piece of coroplast blocking my rad off 100% [slipped inbetween intercooler and rad - sits in the little groove in rad end tanks] and it helps with the engine getting warmer. need to watch the gauge during hwy driving when it is above freezing, gets up to +210°f [don't care about the water temp, but do care about excessive lube oil tempratures - water temp = oil temp ±10°f] but 99% of my driving is stop/go city

i think i need to make something to block off the intercooler so the intake air charge isn't near ambient temps

try blocking off the rad and see if it helps.

 

[RobertP]

mine was doing that too. but it always does when it gets colder outside. i just put a piece of cardboard between the radiator and the intercooler and my temp rises like normal again and stays right at 190-200*.

 

[RMalone]

Even with a cold front there is NO WAY I can get my truck to operating temp in less than 15mi, if the temps are 30deg and under. I am talking about after sitting all night of course. At 10-15deg it will not ever hit operating temps (I assume were talking about 190-200deg), unless the winter front is closed and I'm running at 65-75mph for several miles.



In fact, running empty at low temps and low speed, I doubt these trucks even need a radiator. What they really need is a coolant heater like an Espar or Webasto. Wish I had one I hate being cold. :{

 

[Grizzly]

You may need a new thermostat. However, I agree with what others have already said. Plug in at night.

 

[rbattelle]

I've never run any winter front, and obviously my water temp suffers as a result in the winter.

Nevertheless, I've always been able to reach operating temperature if I drive long enough. Even down to -10°F the thermostat will open within about 20 miles of highway driving.

As others have suggested, try blocking the radiator before doing anything to the thermostat.

Ryan

 

[DPKetchum]

I bet if engine temps don't rise correctly truck should(I think) throw a code for engine too cold etc. All the gas burners will if t/stat is removed or broken . They throw a code for overheat gassers and diesel.

 

[rbattelle]

I bet if engine temps don't rise correctly truck should(I think) throw a code for engine too cold etc. All the gas burners will if t/stat is removed or broken . They throw a code for overheat gassers and diesel.

Good call!



Code P0128 - Thermostat Rationality

Set condition: the coolant temperature does not rise by a calibrated amount over a calibrated amount of time.



The manual points out that the problem could also be an engine fan issue.



Ryan

 

[nickleinonen]

What they really need is a coolant heater like an Espar or Webasto. Wish I had one I hate being cold. :{

me too... .

 

[DPKetchum]

Well just DARN!

 

[RMalone]

Mine heats up normally it's just not going to happen on a 10mi commute to work after a cold night.

 

[KDillard]

see you guys are missing the point here. It reaches the operating temps and once the tstat opens it doesnt regulate the temps. The tsat opens up at approx 180 degrees and the the temp goes from 180 down to about 157 while driving on the highway and it never recoupes to anything above 170. Last weekend I drove for an hour and the truck was under 170 the whole trip after initial opening. Engine temps should not be at 143 degrees afrer running the truck for an hour with outside temps at 34 degrees. It may not trip the code but that dont seem right to me. Id think the tstat would be closed at 165 degrees.

The thermostat will begin to open at 85. 5 - 89. 4°C. (186 - 193°F ). If the valve starts to move before this temperature

is reached, it is opening too early. Replace thermostat. The thermostat should be fully open (valve will

stop moving) at 97°C (207°F). If the valve is still moving when the water temperature reaches 97°C (207°F), it is

opening too late. Replace thermostat. If the valve refuses to move at any time, replace thermostat.

 

[rbattelle]

see you guys are missing the point here. It reaches the operating temps and once the tstat opens it doesnt regulate the temps. The tsat opens up at approx 180 degrees and the the temp goes from 180 down to about 157 while driving on the highway and it never recoupes to anything above 170.

Yeah, that's not normal. Thermostat must be sticking open.



Piece of cake to change it out.



Ryan

 

[DPKetchum]

Please post the results of a new t/stat.

 

[KDillard]

Going in for service tomorrow!!!!

Ok I finally finished doing my own trouble shooting and I am almost 100% its the tstat. I drove on a 50 degree day and temps were never above 175. I took the edge off to make sure there wasnt anything to do with that being on there and drove around for the last 3 days with my snap on microscan plugged in only to find my temps reading the same as before. I also took a infrared thermometer and measured the heater core outlet and the tstat housing at the same reading as the scan tool to verify the acuracy of the sensor. Now with all this time spent and the temps pretty much staying way above freezing I am convinced it needs some warranty work. Appointment is tomorrow at 9 am . Will post back with the results from the trip home from work. By the way I was at 171 degrees on the interstate tonight. Outside temps were 49 degrees and i got off on my exit and sat at the light for +/- 4 minutes and the temps went down to 159 degrees. Definitely not good !! Its gonna really get cold here next month and I wanna have heat on the way to and from work. Wish me luck. :-laf

 

[KDillard]

Well dropped it off at the Dealership and went to work on Friday. They had it till about 3pm when they finally called and said that they wouldnt have a new tstat until this coming wednesday the 26th. No dealerships in this area stock a tstat for a cummins. I said thats fine and picked up the truck. They did however flash my puter for me and went from a version aa-ah. Truck runs much smoother now. Altenator charge at cruise is 14. 7 volts. Now to take the time to change out the oil and fuel filter. The tech there named Bob was awesome to deal with. He let me go through the steps of flashing the computer with him and even enabled high idle for no extra charge. I like that in a tech. I will see bob again probably next friday. Till then I got to deal with a tstat that opens too early and dont close till its bone cold.

 

[KDillard]

Called the dealership this morning and made an appointment to drop off the truck Friday morning before I go into work. They got the new tsat in waiting on me.

 

[KDillard]

this is what my temp was after driving for 20 minutes on the highway at 55 mph . Outside temps were 33 degrees