OM642 care and feeding - PeachParts Mercedes-Benz Forum

ashedd · #1 02-12-2015, 12:45 AM

I have a new to me OM642 powered R320. This is by far the newest diesel I've messed with. I'm wondering how the 642 compares to the older engines(om617 etc) is regards to fuel/oil treatments etc.

I regularly put a bit of 2-cycle oil in with the D2 diesel used in my 617 powered cars. Is that still a good idea with the 642?
Or is it just fine since it was designed to run the ULSD?
Can I use diesel purge?
Is B5 the only mix of bio fuel I can use?
Use diesel kleen?
Can I use "Warren Distribution Howes Lubricator Fuel Additive Diesel Treatment"?
Occasional ATF in the fuel to clean injectors?

From the above list I only regularly used 2-cycle oil and the amber colored stuff known as "Warren Distribution Howes Lubricator Fuel Additive Diesel Treatment", I guess I never really knew the name of it.

I',m sure the biodiesel question has been answered before, please forgive me.

Thanks

PS: Do you think there is ever going to be a need to plug this thing in(block heater) when it's really cold? Never plugged 603's in, ever. But I did sometimes with the 617's.

2.5Turbo · #2 02-12-2015, 02:02 AM

I would avoid adding anything to the fuel or oil except additives that say they're compatible with your DPF. Anything that burns and creates too much ash will eventually plug the DPF; this is why DPF equipped vehicles require low-SAPS oils. At least in my opinion, the high pressure pump and injectors were designed to work with ULSD and the harm some additives may do to the DPF outweighs the minimal benefits to the fuel system.

I'm not 100% sure but I believe up to B20 is OK in the common rail engines. Oil change intervals may need to be shorter when running B20; I know Chrysler lets me go half as long on the oil in my Jeep when running B20. I know all diesel fuel in Minnesota is required to be at least B10 during the summer months and will go to B20 in 2018, so I think you'll be fine.

I would plug in below zero, if anything to get the oil to where it's needed faster. It'll probably start at -20, but the oil won't be pumping as easily as if it was warmer.

ashedd · #3 02-12-2015, 02:45 AM

Oh yes the DPF..

If/when that thing needs replaced I might just delete it from the system. But then I would likely need to get the computer re-tuned.

I'll keep an eye out for DPF computability on additives. Thanks

jcyuhn · #4 02-12-2015, 08:29 AM

I would use no additives at all. This thing does not have the old familiar Bosch injection pump which those were meant to lubricate and preserve.

I don't think mercedes has approved anything more than B5 for this engine.

Since your car is tagged as a CDi rather than a Bluetec, I don't believe it is equipped with a DPF.

I recently saw some postings where the direct injection engines started fine without a block heater down to -10F. Down here in Texas it's never even been cold enough to pergola the thing. Just turn the key and go, year round. It's indistinguishable from a petrol car.

Skid Row Joe · #5 02-12-2015, 09:34 AM

The only weak point of the V6, is the failure of the oil cooler O rings. I'm not thrilled about the V - configuration turbodiesel engines. Just change filters, fluids, and drive.

GregMN · #6 02-12-2015, 10:02 AM

Do not add anything to the fuel or crankcase.

You car does have a PDF.

Use only the approved crankcase oil unless the PDF is sitting on a shelf in the garage.

Your car does not have a block heater. It is not needed.

Green Diesel Engineering does custom tuning for that engine.
They can:
eliminate the EGR cycle and it's flapper motor and any associated codes
if you remove the PDF they can eliminate the regeneration cycle and any associated codes
add about 20% more power at the same fuel consumption
runs smoother and is more responsive.

engatwork · #7 02-12-2015, 10:43 AM

Make sure you use correct engine oil too.

ILUVMILS · #8 02-12-2015, 12:05 PM

DO NOT add anything to the fuel!!! The high-pressure pump, and/or injectors are easily damaged by anything other than ULSD fuel.

ashedd · #9 02-12-2015, 06:59 PM

Quote:

Originally Posted by GregMN

Green Diesel Engineering does custom tuning for that engine.
They can:
eliminate the EGR cycle and it's flapper motor and any associated codes
if you remove the PDF they can eliminate the regeneration cycle and any associated codes
add about 20% more power at the same fuel consumption
runs smoother and is more responsive.

I do want a custom tune at some point. Throttle response sucks on this thing, you gotta really mash it to get it to go anywhere.

How would one know when it's time for a "new" DPF? Is it fairly easy to hollow it out and leave it in place?

It could really use a stiffer suspension, perhaps some parts from the R55. Especially the brakes

Thanks

ashedd · #10 02-12-2015, 07:02 PM

Quote:

Originally Posted by engatwork

Make sure you use correct engine oil too.

Found it at pepboys

Problem is it doesn't seem to burn any oil, but I have a couple quarts just in-case.

Any real world advice on how frequently to change the oil? I do about 60/40 highway vs city driving.

jay_bob · #11 02-12-2015, 11:11 PM

Let the computer tell you when to do the services. It monitors the way you drive and adjusts the change interval accordingly.

jcyuhn · #12 02-13-2015, 07:58 AM

Quote:

Originally Posted by jay_bob

Let the computer tell you when to do the services. It monitors the way you drive and adjusts the change interval accordingly.

Actually, by 2008 it's a fixed 10k mile / 1 year oil service interval. Just change it when the computer tells you. I've had Blackstone analyze the oil after 10k miles on this engine and it had plenty of life remaining.

Oil levels will tend to rise over time on this engine due to the post injection for the DPF recycle. Some of the fuel injected during the exhaust stroke ends up in the crankcase. It's normal. I would suggest only filling to the midpoint of the dipstick when servicing the car. Otherwise the level will rise above the full line over time.

I find it is most cost effective to mail order the ESP oil. Amazon has good prices, of all places.

Skid Row Joe · #13 02-13-2015, 08:11 PM

Quote:

Originally Posted by jay_bob

Let the computer tell you when to do the services. It monitors the way you drive and adjusts the change interval accordingly.

^^^^^
Not necessarily good advise.

The computers aren't calibrated or capable in measuring the parameters of the oil's lubricating performance/capability remaining - to name just one reason why not to depend on them.

Skid Row Joe · #14 02-13-2015, 08:14 PM

Quote:

Originally Posted by jcyuhn

Actually, by 2008 it's a fixed 10k mile / 1 year oil service interval. Just change it when the computer tells you. I've had Blackstone analyze the oil after 10k miles on this engine and it had plenty of life remaining.

Oil levels will tend to rise over time on this engine due to the post injection for the DPF recycle. Some of the fuel injected during the exhaust stroke ends up in the crankcase. It's normal. I would suggest only filling to the midpoint of the dipstick when servicing the car. Otherwise the level will rise above the full line over time.

I find it is most cost effective to mail order the ESP oil. Amazon has good prices, of all places.

Good advise.....

To the point - I had a top-line indy try to tell me the CDI's oil needed changing after about 4K miles on it and the oil filter. -"Because the 'computer' said so."

ashedd · #15 02-13-2015, 11:02 PM

ok, I'll just plan on 10k oil changes. I might actually have to pay to have it done, since I no longer have a garage or even a place to do it. There is a place here in Seattle called strictly mercedes, they have great reviews. They're gonna have to do my maintenance until further notice. The oil sticker on the windshield says it was changed about 1500 miles ago, so I'm good for awhile. Will the service light/msg pop up at 10k from the time it was reset last? I know I can get into it and change that stuff when I need to.

I do have an oil leak, but the dealer said it's coming from the front someplace, they would have to steam clean it to find the leak. BUT the weep hole for the oil cooler is dry, so that's a good sign.

Next I will get the transmission/diff/transfer fluid's changed.

I was enjoying the torque all day today

Even for a 5000 lb vehicle it moves right on out.