TDI Used Oil Lab Analyses Results & Discussions

I could not be happier with the Rotella T6. My engine is running smoother and quieter than ever, and it's now at 183k miles. Just switched from the 505.01 to the T6 about 5k miles ago and I can definitely tell a difference. Quieter and smoother at startup, shutdown and running. I know that's all very non-quantifiable... I'm one of those guys who's very in tune with their cars and can feel and hear every little thing going on.

> I can definitely tell a difference.
> I'm one of those guys who's very in tune with their cars and can feel and hear every little thing going on.

cool, glad youre happy with Rotella T6

I suggest you get some oil tests done, and post your results.

I posted to this thread because it is about oil lab analyses, not about personal opinion as to which oil brand is best. Lots of people have opinions, but, wheres the test?

High iron? Change oil brands?

I have a 2005 Jetta, I have performed two UOA and here are the iron and other info. The oil I am using is Pentosin HP2 5w40.

Miles oil time iron base number nitration

90300 11400 75 3.54 26
99200 7000 74 3.55 15

I have 100000 miles now and just about due for another oil change (last one at 92000)

Thoughts on oil change interval and possibly going to a different oil?

I have used 505.01 since new, the last two changes have been Pentosin.
Driving is a mix of short trips (60%) and longer drives (40%)
Never had the oil changed at the dealer, have used Motul and others.

> Thoughts on oil change interval and possibly going to a different oil?

It seems to me, and I am a newb but have reviewed this entire thread, that your 10k mile interval is fine, per your base number and iron levels, congrats.

IF you try a different oil, my advice is to stay with a 5w40. There is some concensus that Shell Rotella T6 5w40 is an excellent choice. It happens to be the least expensive among the 3 Ive considered.

I currently use a Castrol 5w40. My next change I plan to switch to the Shell 5w40.

Do NOT use a 15w40 (Shell has a cheap one), do not use a 0-30 (all the oil tests with that viscosity have higher iron than 5w40 oils).. whatever you do, stick with 5w40.

Just my opinion. Stay tuned for a more knowledgeable contributor.

Congrats on your diligence in testing your oil, and thanks for sharing your results.

Enjoy the ride!

Samcar222 said:

Guys, firstly I apologize for momentarily hijacking this thread, but I have a silly question...
My JSW is coming on its 40k service (done at a European indy shop that we know well) and currently has 39,300 miles, and its motor oil change was due at 38,800... By the time it gets to the shop this coming monday (earliest appointment, obviously) it will be about 900 miles over the oil interval (39,700)... I know it's fine and it won't hurt the engine, blah bla bla, I'm just OCD and paranoid about my cars ..... to all the oil gurus here.. tell me my car is ok.. And the car is meticulously maintained, with proper Castrol SLX 507.00 as by the book at 10k intervals, correct amount, etc. Of the 700 miles over, most likely 400 or 500 of them were on the highway, which is apparently easier on oil than stop/go (probably 2/3 of the 40k miles on the car were highway driven, to be precise).
Thanks and sorry again for the hijack.
Cheers

Click to expand...

Considering that manufacturers allow for a margin of owner neglect and that most cars are almost never serviced when they should be and still reach high mileage I would say your just fine

Led and silicone is high and only at 2500 miles. What do you guys think?

TDI Smog,

It's hard to evaluate wear rates after a short run. There are always residual wear particles remaining in the engine after an oil change. If you tested the new oil after only 25 miles of service you find measurable wear metal concentrations. Having said that, the levels of Pb and Si are elevated. Has any engine work been done recently?

There is some indirect evidence that unfiltered air is entering the engine. So I'd check the intake tract, air filter housing and CCV system for leaks.

The oil you're using looks like the Mobil 1, Turbo Diesel Truck, which generates consistently good results in these motors. Oil selection isn't an issue here.

TS

Yeah, I changed the cam and lifters out 500 miles before this batch oil. Also I have a massive egr cooler air leak where the valve opens and closes.

That would have been useful information to have. In that case I'd expect the wear profile to settle down over the next 20k miles. The silicon(e) is simply chemical leaching from the new valve cover gasket.

TS

Sounds about right. The lead level worries me. I'm wondering if the turbo is going out :x we'll find out I guess.

Thanks for all the info!

I don't think the turbo bearings have any lead in them. Someone else can confirm???

TS

I think rod bearings have something like lead--> copper--> iron in them...not sure what comes first or last tho...

Generally they're lead, tin and then copper, ie the bearing shells are brass. There is a trace (3 ppm) of tin (Sn) in your analysis which makes sense, given the lead levels.

TS

Recent sample, 10k mile on T6. Viscosity seems high, must be thickening. Previous samples were castrol 505.01 pro oem 5w30.



Double click on icon and it pulls up the Cat pdf. I think.

Ski in NC said:

Recent sample, 10k mile on T6. Viscosity seems high, must be thickening. Previous samples were castrol 505.01 pro oem 5w30.



Double click on icon and it pulls up the Cat pdf. I think.

Click to expand...

1.5 quarts of make up oil added? 100C visco is 14.2 cSt on the spec sheet.

Viscosity is almost never going to stay exactly the same as fresh oil. Causes of thickening include:

1) evaporation of lighter fractions of the base oil and/or additives
2) oxidation and nitration - chemical reactions with O2 and NO2.
3) buildup of soot and silicon

Nothing to see here, analysis results are fine.

TS

Bob_Fout said:

1.5 quarts of make up oil added? 100C visco is 14.2 cSt on the spec sheet.

Click to expand...

1.5 total qt burned. Started off full, at about 6000mi added 3/4qt. At change time it was back at add mark. So only added 3/4qt, but it burned twice that. Not going to top up at change time!

Ski,

Are you running the Rotella T6 in the Cummins marine engine? I'd be interested to see how it holds up under continuous heavy load. Most 5w-40's will shear under those conditions....

TS

Ski in NC said:

1.5 total qt burned. Started off full, at about 6000mi added 3/4qt. At change time it was back at add mark. So only added 3/4qt, but it burned twice that. Not going to top up at change time!

Click to expand...

OK, if you only added 0.75 quarts of new oil over the OCI, it should reflect that.

TooSlick said:

Ski,

Are you running the Rotella T6 in the Cummins marine engine? I'd be interested to see how it holds up under continuous heavy load. Most 5w-40's will shear under those conditions....

TS

Click to expand...

No, I run regular Rotella T 15-40 dino oil in that engine. On that boat it runs a very light duty cycle, cruising at 1100rpm and about 10% load. Not enough heat anywhere in the engine to justify running synthetic. Occasionally I run at 75% power and 2100rpm to blow things clean. I did an oil sample and it came out ok, but copper was high. I think the low load may get some moisture in oil and it leaches the oil cooler. Otherwise, sample ok at 300hr interval.

If fuel prices were lower, I'd cruise at 1900-2100rpm but that's about 12gph (estimated) and that's 50 bucks an hour. At 1100rpm its 2gph (verified over 8500nm).

I know the low load is not the best for the engine, but the fuel prices dictate duty cycle.

I often take oil samples on other Cummins marine engines, and none of these were using synthetic. Even at high load factors, the Cummins samples show good results unless there is an underlying issue such as sea water driven corrosion. Even dino oil holds up well.

The marine engine crowd has not adopted syn oil, except late model MAN engines, where it required. Cummins, Cat, Yanmar do not require it for warranty, even with high specific output.


Bob Fout: You are being picky. It used 1.5 qt. If I never added oil, it would be 1.5qt low and makeup would be zero!! And I think I was in the beers when I filled out the slip, so there.

Ski in NC said:

Bob Fout: You are being picky. It used 1.5 qt. If I never added oil, it would be 1.5qt low and makeup would be zero!! And I think I was in the beers when I filled out the slip, so there.

Click to expand...

I'm not being picky really. "They"/"We" really don't care how much oil was consumed, only how much "new" oil has been added during the interval, as this will skew the results. Take into account how much new oil has "contaminated" the sample and how long ago it was added.

Below is a recent UOA.

Details: Mobile 1 TDT, bypass filter, original cam/lifters, almost all highway commute miles, 3 oz. ZDDP added at about 10K into this interval. I burn between 5% and 20% biodiesel with no additives.

No obvious problems I can see in terms of wear. I'm interested in knowing what the boundary is with regard to interval extension and whether TBN is something I need to be getting on future UOAs. Any/all analyses and comments welcome.

Thanks!

Bob_Fout said:

I'm not being picky really. "They"/"We" really don't care how much oil was consumed, only how much "new" oil has been added during the interval, as this will skew the results. Take into account how much new oil has "contaminated" the sample and how long ago it was added.

Click to expand...

Fair enough. Dilution by new added oil would not change much regarding the numbers in this case.

My thinking with this sample makes me a bit skeptical of those engines that can go a full OCI without top up. Do they consider the oil level drop as I did, are the engines that tight, or a little BS involved??

Oly- That sample looks stellar. Wear metals low, insolubles low, TBN still high, dilution low. You could run that oil longer.... How much longer?? Good question. Others may have an opinion.

Thanks, Ski -- it's certainly encouraging!

Oly,

It's always tough to extrapolate test results based on one data point. However I'd certainly feel comfortable extending this batch of oil out to 20,000 miles based on the overall parameters shown here. As for the TBN limit, if you're using Blackstone labs I'd use a condemnation limit of 25% of the baseline TBN (~ 2.6 for the Mobil 1). If you're testing with other labs using the ASTM "D-4739" protocol (Oil Analyzers Inc., AVLube, etc), I'd use a lower limit of 33% of the baseline TBN.


The TBN may not be the limiting factor in how long you can run the oil. You also have to look at viscosity, soot, silicon, fuel dilution, etc.

FWIW, I don't think doping any oil with supplemental additives is advisable.

TS

TooSlick said:

FWIW, I don't think doping any oil with supplemental additives is advisable.

TS

Click to expand...

Amen to that!

Ski in NC said:

Fair enough. Dilution by new added oil would not change much regarding the numbers in this case.

My thinking with this sample makes me a bit skeptical of those engines that can go a full OCI without top up. Do they consider the oil level drop as I did, are the engines that tight, or a little BS involved??

Click to expand...

All the numbers are affected *some* by new oil. TBN, additive levels, visco etc. 15% volume isn't a lot though, and well within normal usage.

I would say 0.5 quarts is "normal" average oil used for 10K miles for most. If you fill the to max mark (this is not the hash, but the bend) at an oil change, 0.5 quarts puts you at about the middle of the hash at change-out.

Thanks, TooSlick and Scratcher -- I was sort of under the impression that zinc was a primary limiting factor in longevity of the interval -- perhaps not. I also understand that excess would probably not be good for the CAT but that this was't too excessive.

So do you think that the added ZDDP made no difference? Do you think my analysis would be similar had I not added the ZDDP?

Thanks for the input guys!

Oly,

Look at the results of your previous test. You had 1/2 as much ZDDP and the wear profile was essentially the same. You're not going to use up the ZDDP in any oil under normal conditions...

TS