'00 TDI 120k(7.8k OCI) GC0w30

[Thermo1223]

Here we go, first sample.

Bought her back in 2004 with 85k on the clock.

The silicon is my aftermarket foam air filter I thing, ITG for those who follow VW's. It did use RTV on the oil pan though as well, "Right Stuff" in the aerosol can because the drain plug was stripped. The pan was replaced right before this oil was dumped in. It could also be that.

Also the fuel I think is my short tripping to & from in-town places but still in check so no worries there.

 

[Thermo1223]

Also I'll add my that I drive fairly agressively, the motor sees 3k every day and 4.5k weekly. I try and work it as much as possible when I don't short trip to prevent and build-up off soot. I also use ULSD now exclusively.

 

[Tornado Red]

The numbers are very good, except for the silicon, and I suspect you are right about the source. Any other cause and there would probably be other anomalies.

Just curious -- did you observe any improvement in fuel economy running this 30-weight oil versus a 40-weight?

 

[Thermo1223]

Too be honest, it seemed the same as usual. Although I think the engine liked it much more then the Mobil 1 TDT in now. Now the engine just seems louder but it could all be my hearing.

 

[JAG]

It did thicken some and the insolubles are on the high side. Maybe that's typical of GC in diesels...I don't know. M1 TDT will certainly work well.

 

[Thermo1223]

Ya gonna run it to 10k, change they try out some Elf. UOA's for both.

 

[Tornado Red]

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It did thicken some and the insolubles are on the high side. Maybe that's typical of GC in diesels...I don't know. M1 TDT will certainly work well.

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RE: insolubles, aka soot. Oil doesn't cause soot. The UOA only reveals how much soot there is, and how well the oil handled it.

The usual pattern is that new oil gradually drops in viscosity until soot causes it to start thickening again. The wear numbers, the TBN, and the remaining additives -- plus the strong results from other UOA -- suggests to me at least that the GC held up very well and maybe the viscosity didn't drop much at all before soot kicked in. But 0.7% isn't extraordinarily high.

[I'm still very new at this stuff, so take my comments with the usual grain of salt.]

 

[JAG]

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RE: insolubles, aka soot. Oil doesn't cause soot.

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Increased blowby, which is oil dependent, does cause soot in oil.

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The usual pattern is that new oil gradually drops in viscosity until soot causes it to start thickening again.

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GC is almost unique in that it doesn't lose viscosity from shear in most engines.

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But 0.7% isn't extraordinarily high.

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That's the condemnation limit so it has high and getting that high is not the path toward a long term clean engine.

But yeah GC did pretty well, as usual. It can probably be bested by a good HDEO though. Thermo may find out in his next UOA.