last week i changed my oil with Mobil 1 0W-40. before, i was always running pennzoil 5W-40. since the switch, i have noticed im burning oil, there is blue smoke and the smell. its mostly when i first start the engine, it doesnt burn as much when its warm.

someone told me that switching to sythetic on an engine with over 100k miles will cause that, but that doesnt make sense to me. the engine never burned ANY oil before.

do i need to switch to a higher weight Mobil 1? or do i need to go back to dino oil to make this stop? will burning oil in itself cause any damage to the engine?

thanks

__________________
1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

If you are burning a little bit oil while your engine is cold, that is perfectly allright with a engine which has done 100,000 miles with dino oil, the reason is that Mobil-I flows way better than your previous oil and therefore you see some of it escaping when your piston etc. are cold.

Next time use Delvac-I, if you have a diesel or Mobil-I if you have a gasoline engine, just switch to 0W-50.

Switched to Synthetic Oil - Delvac1 5W-40 - after purchasing both the '93 2.5 Turbo and the '82 300D without any reservation over 1 1/2 & 1 year ago, respectively. Neither auto has so far succumbed to what the naysayers claimed: leaking oil and consuming oil; neither needs supplementary topping up between 5K changes. Perhaps I am lucky, though I do not view it as such.
FWIW, Mobil 1 is a fine oil for gasoline engines; however, it is not intended for use in diesel engines. Others may want to jump in here and take issue with that declaration. I would reply by having those with any disagreement call Mobil themselves. I did and learned that Mobil 1 (in whatever multi-grade variety) oils do not possess the additive package necessary to handle the soot which is, of course, a by-product of diesel combustion. Soot may or may not be related to your problem. I agree with Gurkha. Give Delvac 1 a try in place of Mobil 1 for your application. Just my $0.02.

__________________
'82 300D Turbo 204K
'10 Toyota Prius 85K
'13 AMG C63 (P30) 23K
'14 Audi Q5 TDI 46K
'16 RAM 2500 CTD 12K

'10 VW Jetta TDI 65K (traded)
'12 Nissan Leaf 34K (returned end of lease)
'15 Audi A6 TDI 25K (traded)
'95 E320 166K (traded)
'93 300D 2.5 Turbo 168K (sold)

Mobil 1 is now packaging Delvac Synthetic as Mobil 1 Truck & SUV. Just bought it at Wally World $3.88/qt.

Anything starting with 0W is too thin for your Diesel engine. Heavier Mobil-1 is better, but as long as you're spending the money for synthetic, the Diesel specific varieties are best.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Rick,

Why is 0W-40 too thin for diesels? Two of the dealers here in the Dallas area use it for their oil service and it is Mobil1. Without starting another oil thread, it seems to me that pre-98 diesels would benefit from soot reducing oils, but since the 98 and 99
diesels produce comparatively very little soot, that quality might be less important. Also, several techs have told me that since the newer engines have such incredibly close tolerances, the lighter weight oils are called for. Any thoughts?

Steve

btw, I've got a 99E300turbodiesel, and 0W-40 is what Pk. Place has been recommending.

Dealers don't always use what is best for the car. They use what is most convenient and cost effective for the dealer. I first became aware of that though Chris Ecklund, another member of this board, when our E300s were new. His dealer repeatedly used the wrong oil and Mercedes-Benz threatened to void his warranty (or maybe they did) because an improper oil was used.

There is no better proof of my statement than this. A 1999 E300 requires engine oil with a minimum CG-4 rating and no Mobil-1 oil carries that rating.

As for the 0W being too thin, that has been written about by others on this board with much more oil knowledge than me. So you'll have to search the archives for a more definitive answer.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Rick,
Thanks for the oil answers. I still think the issue with Mobil1 and the late model diesels is unsettled, though. On page 1 of the "Factory Approved Service Products October 2000" booklet, Mobil1 synthetic 15W-50 and 0W-40 are among others listed as approved engine oils. It hardly seems right or fair that MBUSA and the dealers would recommend, use at the dealerships, and approve in writing a certain oil and then deny a warranty claim for using that same oil.
But then nothing surprises me anymore. I've never had a car overwhich so much indescision exists as to a what type of oil to use in it. I'm not saying you are wrong--I'm saying MBUSA has been less than clear about proper oil maintenance for the 98 and 99 diesel engines.

Steve

I think the confusion may lie in the date of that booklet's publication. By that time Mercedes-Benz was not selling a Diesel engine in the U.S., so they probably felt no need to say anything about it. All the flavors of Mobil-1 are fine for the entire range of MB gasoline engines, so that made their job easier.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Rick ,I just got off the phone with MBUSA and they told me that the October 2000 fluids booklet is current and valid and tha Mobil1
15W-50 and 0W-40 are both still on the approved list. The Mobil1 website also lists the synthetic 0W-40 as approved for the 98 and newer diesels. The MBUSA booklet states that cars without the FSS ie. pre 98 should use oils with the API minimum classification that you wrote about.

Steve

Old Deis,

The "Spawn of Sam Walton" want $ 4.77 per qt. here in
Savannah!

I know a guy who tried Mobil synthetic in his '92 2.5 turbo (50k miles), and after
a short time it started smoking like crazy, became difficult to start and basically shows
signs of low compression. The guy actually got a ticket becasue it was smoking so bad!
Waiting to see now if a switch back to conventional solves the problem...hopefully the
engine isn't toast.

rant
Personally, I wouldn't run 'ANY' synthetic in an older Benz diesel - if they can go 500+k
miles using conventional oil, it stands to reason that it's probably entirely safe to run...and
that buying synthetic is a complete waste of money and possible risk...that is unless you're
using it for "eco" reasons, in which case I'd stick with a diesel synthetic...and not
anything "0" weight, I think common sense alone should say "don't run that it's too thin"
/rant

well, i guess ill switch to delvac 1 5w-40, i dont know if id rather burn the mobil1 or throw it out. either way, im gunna need a good oil change pump. theres no way im draining that thing into a pan again. anybody know where i can get a good one?

__________________
1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

At a boat store.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

I believe you can buy Pela pumps at any Harley Davidson dealer.

__________________
'91 300D 2.5 Turbo 330K
'00 VW TDI Golf, 190K
'67 BMW R50/2
'73 Norton Commando Interstate