Why would truck run hotter???

[brillmtb]

2003 with 200K on it. Seems to be running hotter than in the past. Possible causes? Was generally not getting much above the 200 mark now can get half way up. Fan clutch, radiator just getting old. Is there an aftermarket radiator with more cores? Thanks

 

[Grizzly]

It could be many reasons; Here are only a few.

1. Sticky thermostat
2. Radiator may need to be cleaned out
3. Low inflation on tires.
4. With 200k on the engine, it may need some work.
5. Fuel injectors
6. Too much load on truck

 

[Bill Lins]

When I replaced my radiator (cracked tank) I was amazed at the amount of debris trapped between it and the intercooler. You might want to check there, also.

 

[BigPapa]

When was your last coolant system flush?

Have you ever cleaned the outside of the radiator and between it and the CAC, A/C condenser, and transmission cooler?

Those would be the first two things I'd look at.

 

[rashwor]

All good suggestions. Also check the fan clutch. If you can't hear the fan roar when it hits ~ 210* F, the fan clutch is probably bad. I changed my clutch about a year ago. I did not have any roar of the fan when it was hot and the old clutch still had a lot of drag on it when you would spin it by had without the engine running; in that regard, it felt like a new clutch and no different from the replacement clutch so that is not always an indication of a bad clutch (excessive spinning by hand).

Also, if the water pump has never been changed, it may be bad as well. I have seen a JD tractor with the impellor blades worn completely off so that no water was being pumped and causing the tractor to run hot. I was amazed that the pump never leaked!

 

[brillmtb]

THanks, will look to cleaning between radiator, drop in new thermostat and I do hear roar, too loud in my opinion, so I think the fan is fine. Will consider water pump next vs just an old radiator?

 

[Tuesdak]

THanks, will look to cleaning between radiator, drop in new thermostat and I do hear roar, too loud in my opinion, so I think the fan is fine. Will consider water pump next vs just an old radiator?

So you are saying the roar of the fan is louder than you are used to? Aside of hot weather... I suggest that this clue is the electronics seeing the engine get hot and locking in the fan to cool it down. So that part of the system is more or less ok with the exception of a weak fan clutch. Aka some roar, but, not enough roar. I would look elsewhere first.

Why the engine is getting so hot and unable to be cooled is covered with suggestions above.

 

[brillmtb]

So you are saying the roar of the fan is louder than you are used to? Aside of hot weather... I suggest that this clue is the electronics seeing the engine get hot and locking in the fan to cool it down. So that part of the system is more or less ok with the exception of a weak fan clutch. Aka some roar, but, not enough roar. I would look elsewhere first.

Why the engine is getting so hot and unable to be cooled is covered with suggestions above.

Its always been loud. I considered putting in electric fans at one point for extra cooling and improved mileage but they are not cheap. Haven't had a chance to look between radiator

 

[Mingoglia]

I'd replace the thermostat with a genuine Cummins part and flush the system and start from there. This is cheap and easy to do. Make sure to burp the system good. If the third gen was like my second, the thermostat had this little bleed hole thing, make sure it's oriented the same way.

 

[Tuesdak]

Its always been loud. I considered putting in electric fans at one point for extra cooling and improved mileage but they are not cheap. Haven't had a chance to look between radiator

Coming from GM's inadequate cooling systems I love this huge electronically controlled clutch fan. Electric fans do not move enough air for anything but maybe a no load daily driver. Last clutch fan for a gas engine I measured had in excess of 10,000 CFM with the radiators in place and hood closed. You can't get more than 5000 CFM freestanding, without radiators and hood closed restriction, on electric fans. Diesel clutch fans have a more aggressive blade pitch and move even more CFM including dealing with the additional CAC restriction. The noise to me is a comfort and means things are working from keeping the AC cold to climbing a grade.

I can buy a lot of diesel for the cost of electric fans. Never mind they don't work well in AZ heat and grades.

 

[Mingoglia]

Coming from GM's inadequate cooling systems I love this huge electronically controlled clutch fan. Electric fans do not move enough air for anything but maybe a no load daily driver. Last clutch fan for a gas engine I measured had in excess of 10,000 CFM with the radiators in place and hood closed. You can't get more than 5000 CFM freestanding, without radiators and hood closed restriction, on electric fans. Diesel clutch fans have a more aggressive blade pitch and move even more CFM including dealing with the additional CAC restriction. The noise to me is a comfort and means things are working from keeping the AC cold to climbing a grade.

I can buy a lot of diesel for the cost of electric fans. Never mind they don't work well in AZ heat and grades.

I agree, particularly with the noise being a comfort. Although I recently moved to GA, I spent 14 years going back and forth towing across the AZ desert back and forth between Southern California. The excess fan noise kicking in meant work was getting done, and the cooling system was doing it's part.