Running a MB Sprinter diesel engine at idle

[barnbnb]

How long is a "safe" time to let the engine run at normal idle speed?
I have seen various opinions on this, but no consensus.

I do know is there are two options that can be dealer installed to increase your idle for extended periods. One is a fixed high idle and the other is a variable high idle option. There is also a secondary alternator that can be installed with a direct feed to the house batteries or in tandem with the chassis alternator.
Many people idle to recharge batteries when boondocking. Dual AGM batteries at 50% take 1.5 to 2 hours at a 1500 rpm idle to fully charge, from what I see on other forums. Other people may simply idle for heat or A/C.

I don't boondock often and I only do an occasional idle of a half hour or so. If I were to do it often and for longer periods, I'd be concerned about the DFP burn-off cycle. It is suggested by some to drive at least 40 minutes at highway speeds after every 2 hours of idling. I'd also want to change the oil more frequently, especially if using any type of biofuel.

If Mercedes will upfit you with a High Idle Option, they evidently have the expectation that the engine can handle extended periods of idling.

Without that option, can anyone document a "safe" amount of time to run the engine at normal idle speed?

[Rkloud9]

Here is a link on the Sprinter Forum that addresses your question.

https://sprinter-source.com/forum/sh...ht=engine+idle

I believe you can search the forum and find many discussions on this issue. Hope this helps.

[kenandterry]

Originally Posted by barnbnb

How long is a "safe" time to let the engine run at normal idle speed?
I have seen various opinions on this, but no consensus.

I do know is there are two options that can be dealer installed to increase your idle for extended periods. One is a fixed high idle and the other is a variable high idle option. There is also a secondary alternator that can be installed with a direct feed to the house batteries or in tandem with the chassis alternator.
Many people idle to recharge batteries when boondocking. Dual AGM batteries at 50% take 1.5 to 2 hours at a 1500 rpm idle to fully charge, from what I see on other forums. Other people may simply idle for heat or A/C.

I don't boondock often and I only do an occasional idle of a half hour or so. If I were to do it often and for longer periods, I'd be concerned about the DFP burn-off cycle. It is suggested by some to drive at least 40 minutes at highway speeds after every 2 hours of idling. I'd also want to change the oil more frequently, especially if using any type of biofuel.

If Mercedes will upfit you with a High Idle Option, they evidently have the expectation that the engine can handle extended periods of idling.

Without that option, can anyone document a "safe" amount of time to run the engine at normal idle speed?

I don’t understand all the questions surrounding idle time of your Mercedes.
You mention you don’t boondock often.
Therefore you should have access to electrical connections to charge your batteries.
Does you motorhome NOT have a generator?

[barnbnb]

Originally Posted by kenandterry

I don’t understand all the questions surrounding idle time of your Mercedes.
You mention you don’t boondock often.
Therefore you should have access to electrical connections to charge your batteries.
Does you motorhome NOT have a generator?

Over the summer we stayed at a state park with no electric available and no generators allowed. Also, we have pulled over for lunch many times in places inappropriate for running the generator.

Yes, I have a generator. But the question I asked is not about generators. I appreciate your input.

[raptor]

I've asked the very same question to the Mercedes servicemen. They can't tell me exactly what to do. The most was 5 minutes long. I've searched and asked and finally I just do it if I really need it.

[MNtraveler]

I'm an MBS owner too. It's just not good to idle diesels other than for a very brief warmup - you can foul up your DPF (diesel particulate filter). Don't use your engine idling to charge your batteries - use your generator. Yes, I know that wasn't your question, but that is actually your answer.

We've stayed at roughly 100 campgrounds in the last few years, everything from fancy commercial places to KOAs, to national and state parks, local campgrounds and state and national forests. I've never seen a place that BANS generators except a few places that have all electric sites where generators are not needed. Everyone else has limited hours which are always more than sufficient to run whatever is needed for cooking and to charge the house batteries. (EDIT: some campgrounds don't allow generators in their tent-only type sections, where only primitive camping is allowed.)

Can you share with us which state park bans generators? I think a lot of us would like to know about this to see if it's true at other parks in that state and also to see if it's becoming "a thing."

[The Evil Twin]

I doubt there is anything special about the sprinter motor, so like any modern diesel you should be able to idle safely. A couple hours here and there will not hurt a thing. Thousands of diesels idle for hours on end every day. A high idle switch/ rheostat is definitely recommended to keep EGT up which helps the DPF and EGR stay cleaner. The DPF will regen and be fine but the EGR only gets passive regen when EGT is high enough. One other thing to consider is oil change intervals- more idle = more often due to soot loading and oil dilution.

[DieselDrax]

Originally Posted by The Evil Twin

but the EGR only gets passive regen when EGT is high enough.

EGR regen? No, there's no such thing. The regen only happens for the DPF to burn the soot to ash.

[The Evil Twin]

Originally Posted by DieselDrax

EGR regen? No, there's no such thing. The regen only happens for the DPF to burn the soot to ash.

Regen was probably not the right thing to say. My intent was to convey that the only way particulate gets any chance to be removed from the EGR is if it happens passively when EGT is high enough- over 600*f. Or by removing it which no one likes doing.

[barnbnb]

Originally Posted by MNtraveler

Can you share with us which state park bans generators? I think a lot of us would like to know about this to see if it's true at other parks in that state and also to see if it's becoming "a thing."

We stayed at Knob Noster State Park in Missouri. Here is info from the Missouri State website regarding that campground:

"The use of generators is prohibited in the campground, unless approved by the park manager. Special consideration will be given for use of generators relating to customer health and safety."

I must assume this is not unique to Knob Noster state park, and probably not unique to Missouri either. We knew that the electric sites were sold out, but never dreamed we couldn't use a generator. From now on I will check in advance before reserving a non-electric RV site.

With temps and humidity both in the 90's we had no choice other than to quietly idle and use the dash air to cool things down before bedtime. And yes, there was no rule against idling your engine in the park. Of course, the MB engine is quiet. You probably could not get away with a Cummins idling.

[babock]

Highly doubt you could even come close to charging a pair of AGMs discharged 50% to full charge in 2 hours. These people are not using battery monitors that say this.

[DieselDrax]

Originally Posted by The Evil Twin

Regen was probably not the right thing to say. My intent was to convey that the only way particulate gets any chance to be removed from the EGR is if it happens passively when EGT is high enough- over 600*f. Or by removing it which no one likes doing.

Ok, but that is still not a thing that happens. There is no passive cleaning or burning of soot to ash going on within the EGR system which is why there is often times a need to remove and clean the EGR components and intake manifold due to soot build-up. Not to mention the temperatures needed to burn soot to ash would destroy components in the EGR and intake manifold, not to mention cause engine fires. Many modern diesel engines have composite intake manifolds that would simply melt if exposed to the EGTs needed for DPF regens.


There is minimal EGR flow during regens and this is purely to help increase downstream EGTs, nothing to do with any sort of EGR cleaning process. EGR cleaning is purely a maintenance/repair item that requires removing the components to clean them.

[The Evil Twin]

Hmm. Ok. I giess I dont understand how a truck that spends its life loaded has and EGR that is significantly cleaner than one that does not. I assumed it is because of higher EGT.

[DieselDrax]

Originally Posted by barnbnb

We stayed at Knob Noster State Park in Missouri. Here is info from the Missouri State website regarding that campground:

"The use of generators is prohibited in the campground, unless approved by the park manager. Special consideration will be given for use of generators relating to customer health and safety."

I must assume this is not unique to Knob Noster state park, and probably not unique to Missouri either. We knew that the electric sites were sold out, but never dreamed we couldn't use a generator. From now on I will check in advance before reserving a non-electric RV site.

It will vary by park, even in MO, as it's not a state-wide policy for MO state parks. You definitely want to check a park's generator policy if you can't get an electric site.


I would say most state parks are likely to have quiet hours and specify that generators, if permitted, are only allowed to run during non-quiet hours and they must also be below a specific decibel level (Which shouldn't be an issue for you, this is mainly to prevent people from bringing noisy open-frame contractor-style generators to parks).


If you avoid the no-generator parks then that will make the idling question/issue generally moot, but may be helpful to others to know the impact of idling a diesel for long periods of time (hours).


If the engine goes into regen and uses a late-injection strategy to increase EGTs then idling will increase fuel dilution of the oil. If a biodiesel blend is used then this can result in sludge forming in the crankcase, is why extended idling isn't recommended, and is why shorter oil change intervals are necessary.


https://www.autonews.com/article/201...y-goopy-sludge


Engines that use a fuel injector in the exhaust to increase EGTs for DPF regeneration don't have nearly the same issues/concerns, however excessive soot in the EGR system is still a concern.

[DieselDrax]

Originally Posted by The Evil Twin

Hmm. Ok. I giess I dont understand how a truck that spends its life loaded has and EGR that is significantly cleaner than one that does not. I assumed it is because of higher EGT.

There's more soot from engines that see more stop-and-go, idling, low-load, etc because more soot is generated under low-boost acceleration and idling. An engine that spends most of its time under constant load and boost is inherently cleaner and more efficient, as such it will generate less soot overall, require far fewer active DPF regens (able to utilize the higher EGTs from normal engine operation to reduce the need to switch to active regens), and generally have fewer emissions-related issues.


Based on the above, you can see that the EGR is staying cleaner while there are fewer active regens going on compared to vehicles that generate more soot and require more active regens. The vehicles with frequent active regens are the ones that are going to be problematic and get caked with soot.

[The Evil Twin]

Gotcha. I'm still learning new things about EPA neutered diesels.
Back to the original point of the thread. Lol. Don't idle all night but an hour or 2 wont hurt.

[FFred]

Buried in an air bag recall post is these words from MB


From the Sprinter Owner's Manual -

If the vehicle is predominantly used for short-distance driving or is stationary for long periods, this could lead to a malfunction in the automatic cleaning function for the diesel particle filter. This can lead to blockage of the diesel particle filter. This can also result in fuel collecting in the engine oil and cause engine failure..

A bit of a run for the genset is far cheaper than a new MB engine installed.

Cars and trucks are prohibited from ideling in about 30 states.

https://www.rd.com/advice/travel/car-idling-illegal/

[barnbnb]

Back to the original point of departure:

Imagine, if you will, a scenario where you are stranded in a blizzard....20 below.....out of propane to run your generator or furnace.....no option for heat other than to run your diesel engine. And you happen to have a full tank of good ol' non-bio diesel.....

Then you think, "I should check my owners' manual to see how long I can idle so I don't void my warranty!"

After having thoroughly read your manual and finding no issue with extended idling, you decide to choose life over death by hypothermia.

You idle your engine overnight for heat and survive to be rescued the next day by a pack of St. Bernards bearing libations.

'Nuff said.

Your engine and emission systems are OK and still under warranty if under 5 yr/100k for engine, 10 yr/100k for emission.

[DieselDrax]

Originally Posted by barnbnb

Back to the original point of departure:



Imagine, if you will, a scenario where you are stranded in a blizzard....20 below.....out of propane to run your generator or furnace.....no option for heat other than to run your diesel engine. And you happen to have a full tank of good ol' non-bio diesel.....



Then you think, "I should check my owners' manual to see how long I can idle so I don't void my warranty!"



After having thoroughly read your manual and finding no issue with extended idling, you decide to choose life over death by hypothermia.



You idle your engine overnight for heat and survive to be rescued the next day by a pack of St. Bernards bearing libations.



'Nuff said.



Your engine and emission systems are OK and still under warranty if under 5 yr/100k for engine, 10 yr/100k for emission.

Yes, there is a difference between doing it once in a blue moon and making a habit out of it. Just like most things, it’s about doing things in moderation or infrequently. That’s not a big deal.

Doing it daily for a week is not the same as doing it once in an emergency.

[TowPro]

Do they make a way to set the engine on high idle like Ram does?
does the engine idle up higher when its running in the cold (like Ram does?)