Do you let your Diesel run while sitting?...Why?

[Phase 3]

I'm new to diesel ownership.

Why do the Pro's leave their engines running all the time? Except when they shut them off.....

I can understand cold weather concerns, but why would the guy hauling a commercial trailer or otherwise, leave the sucker running for no other reason but to simply drive off?

[Texasoilman44]

I leave mine run when I get out of it at short stops. I do this because diesels are inherently hard on starters and batteries. Leaving it run means one less time that I had to crank it over, extending battery and starter life in my opinion.

I did not do this on the first diesel I had 15 years ago, and I replaced quite a few starters and batteries in it. The 3 trucks I have had since then, have had little to no problem with batteries and starters and I have been doing the "leave it run thing" on all 3.

Regards,

Kevin

[hd90rider]

Diesel engines are much higher compression, so therefor harder to crank over. I had the same experience as the last guy, with staters & batteries.

[Dewey Faircloth]

Leave mine running for the comfort of the air condition.May be some thing to saving on the starter.Has 196,000 miles no starter problem.

[RdTxTd]

I don't suppose there's any way to take the key out of these trucks while the engine's still running, is there? For that quick dash into the store?

[carco]

The trend is to shut down the engine if idleing for extended periods, say over 10-15 minutes. In the past diesels were ideled for up to much longer periods of time. One reason is for emmisions reduction, however todays diesels are much cleaner than a few years ago. Another reason is oil dilution and increased cylinder wall wear due to fuel "wet stacking" of cylinder walls and rings. This excess fuel problem is probably more a problem with bigger displacement diesels, ie. road tractor applications. As idleing time mounts, engine coolant temp drops and fuel in the cylinder fails to burn completely leaving wet fuel to accumulate over the rings and walls. This excess fuel will migrate to the crankcase and is believed to also dilute the engine oil on the cyl walls to the point of marginal protection of rings and walls. This raw fuel also increases emmissions as some makes its way out the exhaust. Some diesels idled long periods will actually slobber raw fuel around exh and turbo joints that are not sealed perfectly. This problem is aggravated during cold weather. One solution if extended idleing is needed is to bring idle speed up to say 1050 to 1300 rpm, enough to maintain cylinder temps to adequately burn all injected fuel. The added rpm also helps to circulate coolant faster to more uniformly maintain engine temps. Sorry for rambling, thanks...bob....

[Texasoilman44]

RdTxTd,

I leave the key in the ignition and take the remote for the keyless entry with me so I can lock the doors. If you don't have keyless entry, get a spare key cut so you can lock the doors and still get in.

Regards,

Kevin

[G. Gearloose]

A truck has only has so many trouble-free starts...
why use them up?

[Stephen1]

Most of the problems listed above are problems that have been long solved by most modern electronic injection diesels. Starters are designed for the load and batteries should be fine. Most corporate fleets are mandating that the engine be shut down for anything more than a few minutes. Idling the engine just wastes fuel. If you want to keep the AC or heat running that is another matter.

Look at UPS as an example. They have thousands of diesel delivery trucks. They train their drivers to shut the engine off at every stop they make. Most shut the engine off and roll to a stop. Then start it up and roar off to the next home or business. When they started this procedure their savings in fuel was huge and easily offset any negatives.

Just my thoughts.

Steve

[20050518|4|000086|000000|68.226.176.104]

I've always heard that you should let your diesel idle for several minutes after a long hot drive or pulling a heavy load to let the engine and turbo cool down. Is this still good advise??

[Snowbear]

Originally posted by thunderdude:
I've always heard that you should let your diesel idle for several minutes after a long hot drive or pulling a heavy load to let the engine and turbo cool down. Is this still good advise??

Definitly, it helps to allow the oil to cool down and get away from the engine. helps the turbo as the hot oil wont cooked the bearings in your turbo...

[n3qik]

Most states have some type of law to limit idle time to 15 min. NJ may be 5 min.

[hd90rider]

There are really very few states with an "idle law", & I guess someone forgot to tell the "starters" they have been improved. Have had 2 replaced on this 02 & 1 each on my 98 & 99.