Mobil Delvac 1 2004 VW TDI 14,955 miles

Status
Not open for further replies.
Joined
Oct 1, 2004
Messages
197
Location
Hartford, Ohio
OK gang, here's my latest UOA:

Car: 2004 Jetta GL (PD engine)
Miles on car at time of sample: 125445
Miles on oil sample: 14955
Oil: Mobil Delvac 1 5w40
Oil in service from April 8th, 2007 til August 14th, 2007
Fuel used: Sunoco#2 Diesel, plus 2 tankfuls of B-20 (Sunoco/Soylect blend)
4 ounces of Stanadyne Performance Formula were added at each fillup
Makeup oil added:400ml
Lab used: AV Lube/Predictive Maintenance Services

Iron:60
Chromium:2
Lead:4
Copper:5
Tin:0
Aluminum:9
Nickel:1
Silver:0
Silicon:6
Boron:24
Sodium:27
Potassium:9
Magnesium:423
Calcium:2527
Phosphorus:1181
Zinc:1337
Molybdenum:1
Fuel:A
Water: Glycol:N
Viscosity @ 100C:17.6 cst
Soot:0.8
Oxidation:17
Nitration:12.00

TBN:6.42

Notes: Values in bold font show significant changes from the previous UOA.
Soot exactly doubled (previous number was 0.4) and as a consequence, the oil thickened to nearly a 50 weight and TBN dropped a little. Sodium more than quadrupled (previous number was 6), so I must investigate the possibility of an EGR cooler leak or other problem. (yes the EGR cooler recall has already been performed). Iron rose very slightly (probably from the soot), but lead, copper and aluminum all dropped slightly. Chromium remained the same, and silver was unchanged. Silicon also dropped slightly, so air filtration continues to look good. I'm still using stock oil filtration (Mann filters).

The B-20 was run on two consecutive tankfuls, and barely into the second, the car began to run very poorly. Suspecting a clogged filter, I removed the filter and took a sample which was so dark that light would barely pass through it. I was able to siphon nearly all of the bad fuel out and replaced the filter and refilled the tank with with Shell #2 Diesel. The car ran normally immediately after doing this and has exhibited no problems since. Obviously, the solvency of the B-20 caused the problem since it effectively "cleaned out" my fuel system.

Just to try something different, I switched from the normal BP#2 Diesel to Sunoco. Exhaust soot increased significantly with this fuel.

Aside from the fuel issues, the engine continues to run well, and wear metals remain very good as shown here.

The engine now has over 75k on Delvac 1.
 
Last edited:
Soot is not out of line,you can run up to the range of 2.0 Nit and Oxid are well within limits, synthetic oils can run up to 50.0 cm-1. Oil has not thickened too bad. As soon as you go into a solid and climbing 50wt then change the oil. TBN retention is great. This looks like a 20to25K oil to me!
 
It never ceases to amaze me at how much iron these VW's shed under normal wear. What is the life expectancy of these engines?
 
Soot isn't too bad, but the previous high was only 0.4. I did find a mechanical problem in the EGR/intercooler system which was the likely cause of the high soot and expect the number to trend back downwards. The real concern that I have is with the sodium count. Surprisingly, the lab made no mention of this. Delvac 1 has shown excellent TBN retention, on my last UOA (which had 20k on it), TBN was still a strong 7.52
 
Originally Posted By: D-Roc
It never ceases to amaze me at how much iron these VW's shed under normal wear. What is the life expectancy of these engines?


There are a number of TDIs with 250-300k on them. They do seem to throw large amounts of Fe. Guess that's just the nature of the beast.
frown.gif
 
Originally Posted By: a4tdi
Originally Posted By: D-Roc
It never ceases to amaze me at how much iron these VW's shed under normal wear. What is the life expectancy of these engines?


There are a number of TDIs with 250-300k on them. They do seem to throw large amounts of Fe. Guess that's just the nature of the beast.
frown.gif



On the Pumpe Douche engines (I have one) it look like they are running the cams at the ragged edge of metallurgical limits. If the manufacturing processes were bit off or the wrong oil used, they have a short life. If everything is good, they last forever.

Had I known what I know now I would have gotten a 2003 (pre-PD) instead of a 2005.
 
Hi,

I won't comment on the UOA but I'm interested as to why Delvac 1 5w-40 has become so viscous in this case - especially with sucha low soot figure

In the future it may be wise to consider geting the viscosity readings taken at both 40C and 100C. With diesel engines the 40C reading is quite important

Regards
Doug
 
Originally Posted By: Doug Hillary
I won't comment on the UOA but I'm interested as to why Delvac 1 5w-40 has become so viscous in this case - especially with sucha low soot figure

Good point -- it's thickened well into the 50-weight range.
 
Originally Posted By: Doug Hillary
Hi,

I won't comment on the UOA but I'm interested as to why Delvac 1 5w-40 has become so viscous in this case - especially with sucha low soot figure

In the future it may be wise to consider geting the viscosity readings taken at both 40C and 100C. With diesel engines the 40C reading is quite important

Regards
Doug


Doug,

Delvac 1 has a much higher NOACK volatility than any of the oils VW recommends for this engine. The only drawback (thus far) to using D1 has been increased oil consumption (which I attribute to evaporative loss). Perhaps this explains the viscosity increase?

Cheers,

Mark
 
My understanding is that most Mobil brand engine oils contain some Sodium based additives, and therefore, seeing Sodium in a UOA is to be expected.
 
0.8% soot isn't all that much compared to what it can be, so I'd suspect the significant viscosity increase to be mostly from something other than the soot increase. Would a slight coolant leak account for that much viscosity increase?

The basis for my thoughts are that in one study on soot ("Soot wear in diesel engines"), ~8% soot caused ~22% avg. viscosity increase. Your soot level is only 1/10 of that but your viscosity increase is close to 20%.
 
Jag,

I don't have the answer to your question, but I do have another sample (11k) ready to go to the lab for analysis. It will be interesting to see if the sodium is still as high.
 
Hi,
Mark - I have run Delvac in heavy diesel engines and never seen the viscosity vary more than 1 or 2% from virgin oil! This is on average OCIs 0f 90k kms and out to a max of 130k kms

As well, my condemnation level for soot was 3.5% (DD = 3, Mobil 3.5)
I know that Delvac 1 5w-40 will tolerate soot levels to around 6% without causing increased wear levels. I amd not suggesting this as a limit - 3.5% is/was tops for me. And over millions of kms too!

Perhaps the viscosity number in the UOA report is simply wrong as there is nothing in there to suggest it should be this high!!

Regards
Doug
 
Last edited:
Doug,

You may be correct in that the soot level was a "typo" or some such thing, and thus, incorrect. I do have confidence in the lab but was surprised that they made no mention of the drastically elevated sodium in this UOA. Perhaps that's an error as well?
21.gif


Thanks for your response.

Mark
 
Hi,
a number of diesel engine makers suggest a min of 12.5cSt and a max of 16.3cSt

Some will allow a viscosity increase at 40C of 40% or a decrease of 15%

This is why I suggested earlier that viscosities at both 40C and 100C along with TAN and TBN are IMO very important indicators when evaluating any oil's condition in diesel engines

Regards
Doug
 
Last edited:
My previous UOA had 20k on it, and yet the 100c viscosity was 14.5 cST.
Very solidly still in the 40-weight range and outstanding considering the type of engine, mileage, and usage.
I don't know if this lab will provide 40c visc, but I'll certainly ask. Additionally, I think the correction of the EGR/intercooler problem will allow soot levels to return to normal.
Fingers crossed!
wink.gif
 
Mark,
The Sodium average at the 90k kms OCI point in my diesels using Del 1 was 16ppm

The Sodium average for all Porsche engines I have data on using Del 1 is 6ppm

Fuel dilution to around 2.5% is allowed by most diesel engine manufacturers

Regards
Doug
 
Status
Not open for further replies.
Back
Top