Engine/Transmission (1998.5 - 2002) Warm up time

[tajensen]

How long is sufficient to let a cold engine warm up. In the dead of winter, I was fine with waiting 5 min. to drive, but now that it's nearly 80 degrees, I'm wondering if I still need to let it idle that long.



-Tim

 

[WestTN]

warm up

I start mine and drive away. I did the same with my old truck and put 246,000 miles on it. It still ran better than new with no detectable engine wear. It now has more than 265,000 and runs the same as when I owned it. These Cummins diesels don't need babying. Baby the rest of the truck.



PS: These engines don't warm up very fast with no load on them. Cold running isn't good for them.



My $. 02

 

[WMeyers]

I agree. If you let it idle for 5 minutes that's just about 5 minutes longer that it's running cold.

 

[Joseph Donnelly]

Gas pigs get up to 1200 deg. egt right away idling. In the cold, a diese idles with under 200 deg. egt, not good for it. Put a light load to it, not foot on the floor, but drive it so it can warm up.

 

[Hohn]

Drive it! I fire mine up, let it run about 10 seconds while I put on seatbelt and such and scan the gauges.



Be easy on the RPM when the motor is first running. Short shift it, since this will not only keep RPM down, but place more load on the engine which will help it warm up.



Once you have enough temp to where the needle has moved off of max cold (even a little), it's warm enough for you to drive normally. Once mine is warmed to this point, I wind it up a bit, and cruise around 2K rpm. I have found that cruising around at higher RPM has helped the engine break in and has smoothed it out a lot.



Don't abuse your engine, but you don't need to baby it either. .



Hohn

 

[KWIKKURT]

From cold start up I would wait at least 30 - 45 sec then DRIVE EASY until operating temp is reached. I have seen several blown head gaskets in stock trucks from starting and then running them hard. After it's warm 10 sec onds after OIL pressure is reading should be fine.



We just installed a Cummins 8. 3L 24V ISC and the ECM won't even let you throttle up from idle for about 1 minute.

 

[Idaho Native]

I think there's even something in the owner's manual that talks about the 24V engines being "too efficient" (I don't know if that's the exact wording, but that's what it essentially means) for extended periods of idling. The head loses too much heat and the valves will actually get build-up on them, especially if the coolant temp isn't at 140+ degrees. I believe there was thread on this topic some time back, but I couldn't find it... anyone else seen it?



Loren

 

[KWIKKURT]

I know that my truck will not heat up until I drive it. And when your truck is below operating temp the combustion temps are not adequate for a clean burn. Not necessarily bad enough for gray smoke but probably the Cylinder walls are getting "wet" with fuel.



It doesn't take much load to get you past that cold condition. A Idle speed of 1200+ will usually do the job. And of course a Engine brake is perfect for warm up. I wonder if turning on the A/C so the compressor is running may be enough?



Weather fronts in cold weather are a good Idea.

 

[Sageair]

When it's really cold here (15 below f) or so I let mine idle for about 2 minutes just to loosen the engine up a bit, I also put the transfer case in neutral and put the NV 5600 into fifth gear to let it warm up a might as well.

 

[MD500E]

For you auto transmission guys, drop it in gear to help warm it up. My EGT goes up to about 550-600 when in drive. When its below freezing i do this for about 4-5 minutes. I usually start to get heat out of the vents about a mile down the road.

 

[rspinks]

I also put the transfer case in neutral and put the NV 5600 into fifth gear to let it warm up a might as well

Thanks, good tip.

 

[illflem]

No need to drop an auto into gear for a warm up, N does the same thing.

 

[MD500E]

Dropping into gear loads the engine and raises the egt by several hundred degrees. Definitely not the same as putting it in neutral.

 

[KKaiser]

Auto in gear

I agree with putting the automatic in gear to get a quick warm up.

I do this whenever I'm going to pull my trailer, as there is no such thing as being light on the throttle then. Otherwise the 10 seconds after oil pressure is my rule, too.



Kent