Generally, HDEO starts out around 12.

The synthetic basestock does not influence TBN, the additives do.


Tim

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

Do people get some thrill out of stretching their oil change intervals so they can brag about it? I just don't see the economy of trying to drive over 10K miles on a few quarts of oil when it is by far the cheapest and easiest bit of maintenance you can do to your car. I cringe at the thought of going 20K miles between changes.

I always change mine well before the FSS even comes close to saying to (usually it gives me 12K miles but I change it at 8K). That's less than twice a year for my driving. My oil analyses always come back glowing, everything is low, well below averages and this from a car coming up to 150K miles. OK, maybe it costs me an extra $30-$40 a year because I change it a little early. Compared the other costs associated with driving a MB it is truly not even worth counting! The peace of mind coming from knowing I'm not ruining my engine by squeezing every mile out of the oil is priceless.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Some folks liken frequent oil changes to automotive masturbation.

I think stretching oil changes beyond reason or without data results from a deep-seated guilt complex over having formerly wasted natural resources.

I agree that either extreme is false economy. But I would buy a used car from only one of those folks!


Tim

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

For people really interesting in oil change intervals, please go to the original thread at bobistheoilguy.com under oil analysis diesel auto, and READ.

First off, the guy used the wrong oil. Second, the evidence is clear that he has a coolant leak into the oil that ruined the TBN. Third, he probably never changed the bypass filter at all and that's why the wear metals are so high.

If not for those two mistakes, and a coolant leak, he'd be fine. Of course, it is a VW.

240Joe

You're kinda missing the point Joe, probably due to my poor writing.

Oil analysis saved this guy a lot of grief. It pointed out that, under his conditions and with that given oil (oil that had been recommended for 50k miles by his Amsoil dealer), extended drains would have been disasterous.

I posted this to show the value that oil analysis can bring an individual. Not to disprove a particular interval. I should have been more clear in how I worded my original post.

There are TDI folks who have run Amsoil HDD for 20k miles without any issue. The oil wasn't the problem.

But when you run extended intervals without the benefit of analysis, you may be playing Russian Roulette and not know it...until it is too late.


Tim

__________________
2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

Then you are advocating everyone should get oil analysis then, because even the 3kmile changers could have the coolant issue. That's a fact without or with extended drains.

He used the wrong oil and never changed the bypass filter. If he would have changed the filter, the wear metals would have been more normal and the TBN would have been the issue, clearly from the coolant leak.

The problem I have with oil analysis on these old diesels is that even if I see something that isn't exactly right, I'm not likely to rip into the engine and fix it. These cars can be bought for 1 to 3k$ all day long.

So oil analysis becomes another non-value added process. Interesting, but useless.

240Joe

I have already stated that I think a periodic oil analysis is a good idea. Period. It let's you know if you have issues.

It becomes all the more necessary during a long OCI. How much more glycol and water will enter the crankcase during a 30,000 mile OCI as opposed to a 3,000???

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

Buying another old diesel MB just because you have a headgasket failure or other engine component failure sounds pretty wasteful to me. Spending $1-3K on another car compared to spending somewhere as low as $500-1K for a good, used engine doesn't sound too "value added". I mean, if you won't spend $20 for a UOA (most folks only get those done once or twice a year, so that's about $40 a year), why would you spend hundreds or thousands more for another vehicle?

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Joe

The oil has proven capable in good running TDIs, even for up to 20k.

The fact that the bypass was not changed has very little to do with the issues pointed out in the analysis. If the bypass is plugged, it managed to pull something out of the oil that would not have been pulled out without the benefit of the bypass, otherwise it would not be plugged.

Do you think the bypass was plugged for the entire time? Of course not.

Do you think TDIs without bypasses (at all) explode? Of course not.

Logic says this analysis would have looked worse if there had been no bypass filter. It would have been marginally better if he had changed the filter at 15,000....maybe. I changed my bypass filters on my TDI at 15,000 and that was probably overkill.


Tim

__________________
2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

You don't have to rip into an engine to fix every problem shown by oil analysis.

One common example: You run your oil for 5,000 miles and send the bi-annual sample in. You find out your Si is 60ppm, your Cr is 10ppm and your Fe is 125ppm.

You instantly realize you are sucking unfiltered air into your engine from somewhere. You go out and find a poor connection in your intake and you correct it.

Oh, and my old Benz is worth a whole lot more than $3k!

Tim

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)

Another thing that ought to be mentioned is that not only should the bypass filter have been change before 20k, it should have been changed about 7 times!!

I don't know about Amsoil bypass filters, but the Toilet paper types like my Frantz have a recommended change interval of 3,000 miles for changing the bypass. Change the stock filter every 6k. Add a quart of oil whenever any filter is changed (as the toilet paper will remove about a quart.....)

I think these results only show one thing......... Do your oil analysis so you can make sure your not doing something(s) wrong like this guy was..... Which is just about as obvious as making sure you Buy an EGT gauge before bumping the fuel on your IP.

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-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

The response I got from here: http://theoildrop.server101.com/forums/showflat.php?Cat=0&Number=789793&an=0&page=1#Post789793

I've never heard anyone recommend changing the Amsoil bypass more frequently than 20,000 miles.

The TP filter is a completely different story.

__________________
2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)