Diesel engine warm up time?

[RJCorazza]

Lot of informative posts from knowledgeable diesel operators. I used to "start it up and let it idle for 10 minutes" or so, but have since learned how hard this is on engines, oil, and the environment.
With your prospective diesel pickup, the chances of you wearing it out are slim with a heater, proper warmup and 30-100 mile trips. I preheat my diesel tractor with a block heater even on moderate days (40-50f) so those first couple seconds are a little easier. As for idling after warmup, I will idle for up to 15 minutes at a high rpm (1200) - if I'm out of the seat for longer than that I usually shut down.

 

[Jelly]

IMHO, no, not really. If you have to idle, this is the way to do it. Extended idling periods (over fifteen minutes or so) at "dead-idle" is what's not so good.

No...you're not gonna be hard on your truck. Babying it in my opinion.

On startup in cold weather, I recommend idling a MAX of thirty seconds to establish a full hydrodynamic oil film. After this, just take off nice and slow and just don't romp on it until she's warmed up.

Like you mentioned (and many people don't do this...THEY SHOULD!), it is very good to "idle-down" after a hard run. If you've just been running around, it doesn't really matter that much. If you've been pulling, idle-down a bit to cool off that turbo.

 

[JHZR2]

Start up should consist of a glow cycle, short stabilization idle time (30 seconds or so), then driving. Especially when cold, diesels have a high tendency to build up soot in various places. It is worse if your engine is EGR equipped, so you already have a sticky soot buildup ion the intake as-is. It is best (as it is in any car), to gently drive until the coolant temp is at least halfway between cold and normal. After that, you can push it a bit more, but hard throttle is not reccomended until youve driven at least 15 miles, so the oil is actually up to temp.

The most important thing is to limit boost when the engine is cold. Since diesels make more power by injecting more fuel, and that enrichment curve is based upon an aneroid compensator to adjust for boost, you want to avoid enrichign too much, which will cause less complete combustion due to cold cylinder temperatures, and/or too much heat on various surfaces.

Its best s a general rule to drive gently, as it saves fuel and lengthens engine life, but its especially important in the cold. But watch your boost levels (a turbo gauge helps in this, but 2000 rpm is a typical diesel turbo's max boost area). remeber, no matter how much torqque youre making, diesels are inherently slower than ga$$ers.

JMH

 

[Chris B.]

quote:

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Originally posted by Doug Hillary:
Hi,
it is best to avoid idling a diesel at any time!

Due to the usually large coolant and oil capacities most diesels do take a long time to attain their designed and stabilised "core" operating temperature

We instruct our drivers to stabilse the idle for about 30 seconds then move off and use the minimum revs needed until the idle oil pressure is at the normal "hot" position. In my heavy trucks this can be 20-30 minutes or so depending on circumstances

When shutting off a turbo diesel follow the makers idle down time if noted. We instruct our drivers to shut down when the pyrometer is at its normal flat road running temp or lower!
I never allow them to use the ECM's idle timer!

Regards
Doug

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Doug, You say diesels should never idle but if you go into a rest area all the trucks are idleing. Why is that? Diesels are ment to idle especially when the driver is sleeping in the sleeper. Can you explain this?

Also Diesels are supposed to run hotter then a gas engine in order to opperate properly???? So why is ideling bad?

 

[XS650]

quote:

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Originally posted by Chris B.:


Doug, You say diesels should never idle but ...

Also Diesels are supposed to run hotter then a gas engine in order to opperate properly???? So why is ideling bad?

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Diesels are more efficient than gas engines. Under some idle conditions, they don't generate enough heat to keep the cylinders at a good oeprating temperature range. This is also partly because diesel aren't throttled, so at idle, there is a lot of excess air going through the engine. This helps keep the internals of the engine even cooler. That's one reason some diesels have a fast idle setting for prolonged idling. They do more work at a fast idle, so stay warmer.

 

[marvinlee]

What is really amazing is that after years of debate over warmup time, no manufacturer has published authorative research on this topic. Partly, the issue may be engine-specific. On my Kubota tractor, the instructions are firm: Do not apply any load until the engine has run five minutes." Thats it! No allowances stated for outside air temperature, type of oil, or kind of load.

My view is that most engines are relatively insensitive to type of warmup. That view is based on the fact that engine makers must design their engines to achieve satisfactory operation from an extremely diverse population of engine operators. Even the very large stationary Caterpillars and Cummins start cold and run to full load immediately when used for nuclear plant power generator backups. Yes, they probably have a shorter life as a result.

 

[cryptokid]

in my dads dodge 2500 with cummins turbo diesel owner manual it says to idle the thing for atleast 5 minutes before driving away, and drive it real easy untill the coolant temp gauge reads the normal tempature.

the way i understand it is this. when an engine is warming up, the very first thing to start heating up is the pistons and rings. this is because they have a relativly small mass and are directly exposed to the heat. when pistons and rings heatup they expand, and the cylinders and head do not heat up as quickly as pistons because they have more physical mass. so you have a condition where you have fairly hot pistons in a relativly cool cylinder. this can led to scuffing of the pistons rings and cylinder because the cylinder has not gotten hot enough to expand outward and provide enough space for the pistons rings and oil layer.

somthing else interesting to note is that if i remember correctly, certain aw and fm additives do not work properly untill they reach a certain tempature. starting youre engine and simply driving off may render these adds useless untill the oil warms up.

on every engine i own, from my chainsaws to my car, i let the engines idle a few minutes to warm up, and if i have been running the **** out of them, i let them idle for a fre minutes to cool down.

 

[Cyprs]

I bought my first diesel 7 months ago in cold bitter January, -50 here with windchill, that is nearly the same in C or F. Inexperienced in diesel, I idled it as I do a cold car engine, 5 min and 10 min when extremely cold. My diesel oil change showed no dilution.

I ignored my 1992 Dodge Cummins diesel manual's 30 sec idle and drive off gentle as Government energy and enviromental lobby via Dodge. I then got into this exact same forum and read it this spring, I then believed my manual to be true, that ended my conspiracy theory.

I have been idling my diesel 30 seconds to 2 minutes and then gentle drive off for ten minutes min. since spring.

Today I read Cryptokid's post. He has a Dodge manual that suggests a 5 min idle, my exact first inexperienced instinct, I still dont know what to do with warm up idle, one has to take Dodge's 5 min idle seriously into consideration. What year is your Dad's Dodge Cryptokid?

Cyprs

 

[Gene K]

quote:

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Originally posted by Cyprs:
I bought my first diesel 7 months ago in cold bitter January, -50 here with windchill, that is nearly the same in C or F. Inexperienced in diesel, I idled it as I do a cold car engine, 5 min and 10 min when extremely cold. My diesel oil change showed no dilution.

I ignored my 1992 Dodge Cummins diesel manual's 30 sec idle and drive off gentle as Government energy and enviromental lobby via Dodge. I then got into this exact same forum and read it this spring, I then believed my manual to be true, that ended my conspiracy theory.

I have been idling my diesel 30 seconds to 2 minutes and then gentle drive off for ten minutes min. since spring.

Today I read Cryptokid's post. He has a Dodge manual that suggests a 5 min idle, my exact first inexperienced instinct, I still dont know what to do with warm up idle, one has to take Dodge's 5 min idle seriously into consideration. What year is your Dad's Dodge Cryptokid?

Cyprs

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If you read Doug Hillary's post you willl see he stated "Idle for 30 seconds ONCE IDLE STABILIZES, I have never started a cold diesel at less than -10F (-23C) but can assure you it will take several minutes for the idle to stabilize.

Contrary to Doug Hillary's post if you shut off a Diesel at -50F (-46C) you are a braver man than I. OF course I most likely would have the idle kicked up to 1200 rpm + in that case with the nose downwind and a radiator cover.

BTW Dodge knows @#$% about Diesels. I would go with Cummins recommendation for the 5.9L.

 

[theguru]

Whilst Doug has a lot of experience running a fleet, I'm not sure that he would get a lot of -50F starts here in Australia. Gets fairly cold in the Alps, but even then -50F?, dont think so.

 

[Cyprs]

Thanks Gene, makes more sense to me in waiting 30 seconds AFTER the idle stabilizes, my 92 manual states to idle 30 seconds and drive off gentle.

I actually live in the "banana belt of Saskatchewan" here, we are generally 15 C warmer here than anywhere else in Sask., we get the tail end of chinooks from rocky mountains farther to west in Alberta, colder than usual winter this past year.

thanks,
Cyprs

 

[Gurkha]

This topic had been hotly discussed in the MB forum and the engineers at MB reccomended that the engine should be driven as soon as there is oil pressure as warming up MB diesel engines leads to excessive carbon build up.

 

[RC]

quote:

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Originally posted by cryptokid:
in my dads dodge 2500 with cummins turbo diesel owner manual it says to idle the thing for atleast 5 minutes before driving away, and drive it real easy untill the coolant temp gauge reads the normal tempature.

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I'm finding this very hard to believe. What year is the truck?

 

[bulabula]

In my 2003 RAM Truck Diesel Owners Manual, all it says (concerning any 5 minute rule ... anyways) is if temps are below 32F (0C), operate the engine at moderate speeds for 5 minutes before full loads are applied.

It also gives a mediocre discussion on wet-stacking and fuel dilution concerns about prolonged idling too - which I agree with, but have still idled it "prolongingly".

Me? I let the oil pressure come up to normal, then drive away easily (keep her under 1800) until the temp needle rises off the stop (about 140F); then I can pull the trigger and let her rip.

Truck is an '03 Dodge Ram CTD HO/6 speed.

 

[blano]

In my 01 Cummins/dodge I use a high idle device to warm it up in the winter. It works great and I have been doing this since new with excellant uoa's. The main problem with idling is that it leeds to fuel contaminating the oil.

 

[cumminspuller]

I have a 99' Dodge 3500 CTD. I have 243,000 miles on it and usually do not let it idle to long. If I am just stopping for 5 or 10 I let it idle depending on outside temperature. I just try to use a bit of common sense. Just what I have done for the last 4 years and UOA come back great.

But my main reason for replying is I just bought a 1997 FL-50 with a Cummins 8.3C. It has no fast/high idle feature. Since this truck has a sleeper and I will be spending a little bit of time in it, is there somewhere or something I can buy to *** this feature? Being that it is a pre-electronic engine I am hoping there is something available.

How about starting the truck? My dodge has a wait to start light to let the heater cycle. I have noticed on a few friends big trucks they don't seem to have this, including the FL-50 I just bought. Why do these trucks not have this option? Other than plugging it in in cold weather, how about when no plug is available?

Jason

 

[Steve S]

There are various diesel powered bolt on devices that keep the coolant somewhat hot when you park over night. I don't remember what they are called . A device with a generator would be nice.Also a porta pottie so as not having to get up and dress ,to walk into the truck stops bathroom.

[ July 10, 2004, 09:51 PM: Message edited by: Steve S ]

 

[Neil Womack]

I have no real experience with this. However, when spending summers riding with my dad (cross country truck driver) he used a notched broom stick between the steering wheel and the throttle to keep the RPMs up.

 

[cumminspuller]

Thats not a bad idea. If I can not find anything else I will give that a try.

Jason

 

[budweiser]

i idle my m.benz before driving, only a short time.