I changed my oil yesterday. Previously I had put in rotella 5w40 back in October. I was just shy over 4800 miles.

I changed it and collected a sample for a Blackstone oil analysis. It was changed hot.

The oil had a distinct burnt smell. Not like burnt toast, but burnt smelling. I can't really compare to what it smells like.

I know the oil analysis will tell me a lot when it comes back, but I can't wait 4 weeks for that.

Why would motor oil smell burnt? A google search says it's oxidation, but the article was for a gasoline engine and not a diesel one. Should I be particularly worried?

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-Typos courtesy of my mobile phone.

Have you burned only your normal diesel fuel from your usual source?

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Gone to the dark side

- Jeff

"Dino" Rotella OR the Synthetic...
ONLY 3,000 Miles between oil + Filter changes.

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'84 300SD sold
124.128

Oh goodness. I was overdue for a change by 1000 miles I'll remember that from now on.

I only burn what is sold at the pumps. Up here it's strict D2 ulsd. I've never seen any biodiesel blends.

Any tips on extended change intervals? I do a lot of driving up while I'm at school and the parking lot isn't a very good place to change my oil. Right now I put in two gallons of Mobil 1 5w40.

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-Typos courtesy of my mobile phone.

Normal dino oil has an odor hot we are used to. There is no reason I can think of that the synthetic may also have it's own distinct aroma.

The engine was never hot enough to burn the oil I would think. Even the oil going through the turbo bearings travels fast enough usually to avoid that.

You may have discovered a way to tell the type of oil in an unknown engine by noticing this. Or you have started a dip stick smelling contest.

4k miles isn't much, and the smell doesn't mean much. Wait and see what the lab says.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Back in early fall when I changed the oil from the Rotella 15w40 dino the oil didn't smell like anything.

The smell when i was changing this was just a big surprise for me. I will post the results back when they come in due time.

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-Typos courtesy of my mobile phone.

Speculation: at 336,000 the Exhaust Valves/Guides/Stem Seals are worn and you are smelling Exhaust in the Oil.
I suppose the same could be said for the Piston Ring Seal/Land area on the Turbo Charger Turbine Wheel.

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84 300D, 82 Volvo 244Gl Diesel

Up until 1 year ago I had been using Gasoline Engine type Oil in my Mercedes.
I have done 2 Rotella T regular 30wt Oil Changes and the Oil is always a lot blacker than when I used the 30wt Gasser Oil.

From what I have read extended Oil changes are most ofte done with synthetic Oil. Or, regardless of the Oil used; by folks who have installed a low micron by-pass Oil Filter system.

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84 300D, 82 Volvo 244Gl Diesel

Gasoline Engine oil? In a diesel? Why? And I thought that was a big no-no.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Let's talk about this.

I understand that the 3,000 mile oil change interval may no longer be valid as a blanket rule. Going back 30 years or more, oil chemistry was not as evolved as it is now. Much of what is depleted in oil are the additives, such as anti-foam, rust inhibitors, etc. These chemicals as I've understood it, lose their potency long before oil viscosity moves in the wrong direction.

I will support that the soot created in the diesel engine will soil the oil and of course one has to assume that while miniscule, those particles can cause additional wear, but is this beyond the scope of the oil and filter's normal job?

I will also support that an ounce of prevention is worth a pound of cure.

Oil from my MB does have a different aroma than oil from my Honda. My Honda has oil change intervals that are often 6,000 miles plus. My previous Mercedes ML350 only required oil changes every 10,000 or so.

I do believe that oil is more durable than we give it credit for, and certainly much longer than what oil change shops prefer.

Is there new research stating that 3,000 is the limit for conventional or synthetic oil? If so, I'm unaware and would like to read it.

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This area is typically used to brag about one's current or former automobiles.

I use Blackstone too. If you Priority mail the sample tomorrow (Friday) they will have it by Tuesday and you should have an analysis in your email by Thursday.

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Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K

I just freaked and thought the smell indicated something abnormal. It was immediately apparent to me when I pulled the little test cup away from my oil collection bucket and i held it closer.

I'm anxious to see the results of the oil analysis. I'm just being overly paranoid at this point, but I am curious to see if it is worth continuing to repair the little odds and ends in this car. If something major happens to this car I won't be able to swallow the repair costs right now. In the summer i'm going to do a compression test to REALLY see where I stand in terms of repair.

Edit: Sweet, I sent the sample in yesterday. So Wednesday sounds pretty good in my opinion.

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-Typos courtesy of my mobile phone.

'Detail please the Great Pleasure experienced ,when last you R+R ed your
engine to replace worn: Rings,Bearings,Etc.,Etc.

(Delvac 1 and Mobil Truck+SUV[Or whatever they're calling it this week] are
ALMOST as good as class IV Synthetics like Redline.)

Although the Diesel additive packages in Shell's Rotella products are superior
to Mobil's...The Dino Rotella T 15W40 is a non-synthetic [oil+filter every 3k]
AND unfortunately the Synthetic Rotella T 5W40 is substandard to Mobil's
class III synthetics,So [oil+filter every 3k for it too].

I use the Rotella T Synthetic 5W40, But only for 3K miles, MAXIMUM.

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'84 300SD sold
124.128

Also, Blackstone will email you a PDF of the analysis the day they do it, which is often the day they receive it or the day after.

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1985 300SD 99K