how long to warm up motor

[Zoafan]

Why is it bad to let a diesel idle? How long is too long to let a diesel idle?

[MartinP]

I once read some where that the reason not let a diesel idle to long(what ever that means, depending on engine manufacture) was to prevent varnish building up in the cylinders. Well, tell this to the truck drivers who leave there engine idling for a prolong period of time. For me, I'm not real concerned leaving the engine idle to warm prior to driving. I do this with my car, bike and aeroplane and have never had any problems. To me warm oil circulation is more important as well as heat in the cylinders. Besides, Cummins had engine block cracking issues on the #53 ISB and recommended that the engine water temp was up prior to driving. I really think the bottom line here is to get some sort of heat into the engine prior to operation.

Martin

[wa8yxm]

A few minutes then use LOW gear (or drive slow enough that the transmission in Drive never gets out of low) till you are out of the park.

To get it up to temp at idle will take a long time, way more than what the word "Excessive" in the owner's manual says.

Plus it will annoy the blazes out of your next site neighbor and his next site neighbor, and the guy on the site behind you and across .. Well you get the idea.

Better plan yet.. Use block h eater pre-warm engine BEFORE starting, then let it idle a few minutes to COOL to operating temp.

[JohnBoyToo]

wa and I are on the same page here,
plugging in helps the start a bit,
but is usually more trouble than it's worth for us...

idling will never warm up a deezle - even at high idle...

and did someone say let it idle to warm up the wheel bearings and tranny ?!?

sorry, but if idling doesn't warm up the engine, it certainly won't warm up those remote parts especially if they are not turning ....

[Ernie Ekberg]

Or- turn on your block heater

[laj]

Originally Posted by JohnBoyToo

wa and I are on the same page here,
plugging in helps the start a bit,
but is usually more trouble than it's worth for us...

idling will never warm up a deezle - even at high idle...

and did someone say let it idle to warm up the wheel bearings and tranny ?!?

sorry, but if idling doesn't warm up the engine, it certainly won't warm up those remote parts especially if they are not turning ....

if you would read my post correctly you would be able do discern what i was saying. warm up the engine which for me takes about 15 min. by the time i have everything disconnected, and the toad hooked up. then start out slowly and let the bearings and tranny warm up at a slow pace under low power. not sitting there like an idiot waiting for the tranny gauge to show temperature on it. If your thermostats are working correctly your engine H2O gauge will come up to around 170 while idling in about 15-20 min

[palehorse89]

If it is cool out (50deg) I turn on the block heater when I go to bed, In the morning when we are ready to leave I unhook everything except the electric and close the slide, hit the HWH button and start the jack retract process and start the engine (block heater turned off now) engine temp is at 120 deg.
Go out and unhook the electric , do a jack up check on all 4 jacks and make sure the stored and a double check on everything outside, air dryer blew off, coach up, back inside (now it is have been 5 min. max) pull out and leave slow. I try run my engine (respect to the people around me) for the shortest time I can just to get it aired up to move it. Now it is up to 140-150 deg. and it dosn't take to long slowly going up the road for it to get to 180 deg. , by then tranny temp. is also coming up.

[Ray,IN]

Everyone remember, we are on the Duramax forum. This is a light-duty diesel engine, that warms up relatively quickly.

At low idle a diesel engine does not efficiently burn all the fuel in the combustion chamber. This contributes to cylinder "wash-down" (washes the oil film off the wall). This wash-down also allows fuel into the crankcase over time. I could say more, but I would be repeating what you will easily find with an internet search.
No light or medium duty diesel engine mfgr. I know of no mfgr. who recommends idling the engine for longer than 10 minutes.The main reason is engine inefficiency at low idle. A diesel engine will never reach normal operating temperature at low idle. In fact, an engine at normal temperature will actually cool-down at low idle.
The ignorant folks who let their RV sit and idle for 30 minutes before departing the CG are actually doing their engine harm according to all the search results I have ever found. Today several states and cities have idling laws stating no more than (usually) 10 minutes. Those also may be found with an internet search.

[MartinP]

Folks, Ray In is correct we are on the Duramax forum. We all know that there are different makes and models with different horsepower and mass. Some are going to warm up quicker than others. There a number of factors that come into play such as ambient air temperature, mass of the engine, fast idle/ slow idle, manufacturer. From what I can see on the internet at various sites the biggest concern as mentioned in early post is glazing and cylinder cool down. All are correct when they say refer to the operators manual. For those who don't have a manual, call the tech support line and ask. Other folks are correct also when stating be considerate to your fellow campers and neighbors. Again as I stated in a previous post get a little heat in to the engine before driving and certainly allow the temps to reach close to normal prior to placing the engine under full load. My views only. Enjoy the life we have being able to do this.
Martin

[fvstringpicker]

I usually crank it and drive it around the neighborhood. By the time I back it and hook up, its approaching operating temp.

[caissiel]

Originally Posted by JohnBoyToo

The best warm up is slow driving... just ease off and let the gearing get you going...

otherwise your idling is contributing to that dastardly global warming and Al Gore will come get you (When he's not counting his oil money )

Same for me and in 40 years I never could warm an engine enough or fast enough by idling it. Just start and take off. Drive easy till water temperature is above low mark. Uusaly less then a mile. That's at low outside temperature of -20F. Summer time I never worry. And I had VWs,GM and now a Ford Powerstroke. The EGR would cause problems if I idle it to much, its key on and go and when stop key is off. I was told one time that my VW did not smell like a diesel well there is the benefit of not idling.

[HTFireMedic]

Originally Posted by Zoafan

Why is it bad to let a diesel idle? How long is too long to let a diesel idle?

I have been in fire and EMS for 20+ years. We often let our trucks idle for an hour or more. Some have fast idle, some don't.
That being said, our engines are no different than any other Diesel engine. We have to maintain ours, often by the hour meter not mileage.
I have not had a problem with extended idle, other than more carbon in the exhaust system. Our NAEVT (emergency vehicle technician) said that we needed to bring them up to temp and "run the hell out of them" quarterly. He said that this would remove the carbon deposits.
I believe that several hours of consecutive idle time at low idle would be worse that an hour at fast idle, there again each opinion is different.

[JohnBoyToo]

Originally Posted by laj

if you would read my post correctly you would be able do discern what i was saying. warm up the engine which for me takes about 15 min. by the time i have everything disconnected, and the toad hooked up. then start out slowly and let the bearings and tranny warm up at a slow pace under low power. not sitting there like an idiot waiting for the tranny gauge to show temperature on it. If your thermostats are working correctly your engine H2O gauge will come up to around 170 while idling in about 15-20 min

no harm no foul laj

not intended to be personal, but if I took it wrong others may too, so just wanted to clarify... as stated, started and driving our RV is a nice problem to have

[laj]

JohnBoyToo,

Agree, no harm no foul. Not that I would do it to mine but there is a way to warm the tranny without leaving.