09 Volkswagen Jetta 2.0T (146k Miles) 7600 OCI

[davizzel]

Hello Oil Gurus,

This is my first oil sample sent to be analyzed. Car is driven daily about 80 miles, 70% Highway -30% city. I have added no additives, this was the first time using Mobil 1 OW-40. Please provide any input or suggestions I guess, not sure what I was looking for having the oil analyzed in the first place.

09 Jetta 2.0T (Gas)
146K Miles
7600 OCI - Mobil 1 Ow-40

 

[RooflessVW]

When was the last time you replaced your cam follower?

 

[Virtus_Probi]

I don't think 44ppm of iron in 7653 miles sounds great compared to an average of 24ppm in 6200 miles...the former is a nearly 50% higher wear rate than the latter.
Guess Blackstone isn't alarmed...

 

[davizzel]

Originally Posted By: rooflessVW
When was the last time you replaced your cam follower?


I have never replaced this in the 5 years of ownership, purchased car with 60k miles.

 

[davizzel]

Originally Posted By: Virtus_Probi
I don't think 44ppm of iron in 7653 miles sounds great compared to an average of 24ppm in 6200 miles...the former is a nearly 50% higher wear rate than the latter.
Guess Blackstone isn't alarmed...


What might be the cause of this?.....I just noticed the difference.

 

[zorobabel]

I'm not saying that this is the cause but it does rhyme with the "Mobil 1 produces more iron in UOA's" school of thought.

 

[OVERKILL]

Both silicon and sodium are elevated and warrant investigation. Silicon points to an air intake tract leak, which would cause an uptick in iron and aluminum, and sodium could conceivably be as well, if what it is ingesting is road salt. Could also point to coolant though.

 

[davizzel]

Excuse the ignorance, how does one determine if coolant is indeed making its way through.....Also, I do live in Chicago where road salt was heavily used this winter/during this oil cycle.

 

[OVERKILL]

Originally Posted By: davizzel
Excuse the ignorance, how does one determine if coolant is indeed making its way through.....Also, I do live in Chicago where road salt was heavily used this winter/during this oil cycle.


Is your coolant level changing in the overflow? Have you had to add coolant? That's the easy way to check. You could also have the system pressure tested if need be. I'd start with looking for an air intake tract leak first, however.

 

[davizzel]

Originally Posted By: OVERKILL
Originally Posted By: davizzel
Excuse the ignorance, how does one determine if coolant is indeed making its way through.....Also, I do live in Chicago where road salt was heavily used this winter/during this oil cycle.


Is your coolant level changing in the overflow? Have you had to add coolant? That's the easy way to check. You could also have the system pressure tested if need be. I'd start with looking for an air intake tract leak first, however.



Haven't added any coolant, but will definitely check the air filter box and attachments. Appreciate the info.

 

[RooflessVW]

Originally Posted By: davizzel
Originally Posted By: rooflessVW
When was the last time you replaced your cam follower?

I have never replaced this in the 5 years of ownership, purchased car with 60k miles.

Your iron level says it's time.

 

[davizzel]

Originally Posted By: rooflessVW
Originally Posted By: davizzel
Originally Posted By: rooflessVW
When was the last time you replaced your cam follower?

I have never replaced this in the 5 years of ownership, purchased car with 60k miles.

Your iron level says it's time.


Thanks, never heard of this being a problem on the MK5's, looks like a fairly quick repair.

 

[OVERKILL]

Originally Posted By: davizzel
Originally Posted By: OVERKILL
Originally Posted By: davizzel
Excuse the ignorance, how does one determine if coolant is indeed making its way through.....Also, I do live in Chicago where road salt was heavily used this winter/during this oil cycle.


Is your coolant level changing in the overflow? Have you had to add coolant? That's the easy way to check. You could also have the system pressure tested if need be. I'd start with looking for an air intake tract leak first, however.



Haven't added any coolant, but will definitely check the air filter box and attachments. Appreciate the info.


Let us know what you find

 

[Hammehead]

Now I keep looking to every 0w40 reported viscosity ... and this one has sheared.
5cst base with VII ...

 

[davizzel]

Originally Posted By: Hammehead
Now I keep looking to every 0w40 reported viscosity ... and this one has sheared.
5cst base with VII ...


Can you explain that in English to a newb?

 

[OVERKILL]

Originally Posted By: Hammehead
Now I keep looking to every 0w40 reported viscosity ... and this one has sheared.
5cst base with VII ...


A lot of the time, you see viscosity loss and it is due to fuel dilution, but in this case, I believe you are correct, that we are seeing the result of shear, based on the flash point still remaining reasonably high. It is actually a relatively low viscosity xW-30 at this juncture.

 

[OVERKILL]

Originally Posted By: davizzel
Originally Posted By: Hammehead
Now I keep looking to every 0w40 reported viscosity ... and this one has sheared.
5cst base with VII ...


Can you explain that in English to a newb?


Basically your typical PCMO is a blend of base oils that reach a certain viscosity target, and then Viscosity Index Improvers are used to thicken it up, whilst PPD's are used to keep low temp performance acceptable.

Assuming this is the "FS" version of M1 0w-40, it is primarily GTL-based, and likely uses a light base oil blend that is then brought up to the 40 designation, whilst retaining the 0w-xx cold temp performance spec, via the manner described above.

Now, when we see viscosity loss in a UOA, it comes from two sources:
1. Fuel. Fuel dilutes the oil and makes it thinner. This is accompanied by a decrease in the Flash Point of the oil.
2. Shear. Mechanical action on the VII (polymer) compounds in the oil actually breaking them apart, which causes permanent viscosity loss.

Since your Flash Point is still around 400F, that indicates little fuel in the oil. This means that the majority of your viscosity loss is due to the VII's being sheared, leaving less of them to prop up the viscosity and resulting in a thinner product. In this case, an oil that is in the lower range of an xW-30.

 

[davizzel]

Thank you, incredible the knowledge possessed by members here.

 

[OVERKILL]

You are quite welcome.