Last post on Nov 17, 2013 at 8:38 AM
You are in the Volkswagen Jetta
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Volkswagen Jetta, Biodiesel, Diesel, Sedan
#4437 of 4777 Learned something interesting about the new TDI engine (2009+)
Dec 31, 2010 (5:17 pm)
Still shopping for a replacement for my Jeep. Looked a t left over 2010 Jetta Sedan TDI. Nicer ride than the 2011 Sportwagen TDI but there was more engine noise intrusion at idle.
I asked several questions of the tech concerning how the DPF regenerates. Turns out that they could not (VW diesel techs) could not answer this. But what I did learn is this, there is no extra injector/valve to dump fuel into the exhaust stream to cook the soot so the only other way to do this is to spray some fuel into the combustion chamber at the end of the exhaust portion of the cycle when the exhaust valves are open. Now this is not without its consequences. As I have read, not all of this fuel gets exhausted/pushed out of combustion chamber and some does remain and gets on the cylinder walls, thinning out the oil film on them. Also, some does get past the rings into the crankcase causing oil dilution and a reduction in lubricating power.
The Einsteins (sorry Albert) at VW may or may not have taken this into consideration but some of the major U.S. diesel engine manufacturers including Cummins and Caterpillar have issued bulletins for their newer engines calling for more frequent oil changes because of fuel dilution of the crankcase oil.
With this in mind, it would behoove the owners of the newer TDI (2009+) to consider more frequent oil changes say every 5000 miles versus the 10000 miles VW calls for.
#4438 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [winter2]
Jan 01, 2011 (8:53 am)
While that very well might be a very logical conclusion, there are a host of variables that make it more complicated. Suffice to say I would have no issues doing 20,000 to 25,000 miles OCI's.
Part of the VW 507 specifications is to be able to go to 31,069 miles (aka 50,000 km).
#4439 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [winter2]
by MrShift@Edmunds HOST
Jan 01, 2011 (8:56 am)
Any concerns could easily be addressed by doing an oil analysis to either prove or disprove the possibility of fuel dilution. If your oil checks out just fine at 5K, do the next analysis at 7.5K and if that's good, then go to 10K without worries from that point on in the car's lifetime.
#4440 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [Mr_Shiftright]
Jan 01, 2011 (10:00 am)
Yes that is really one of the best ways. In fact (on another more VW specific cite) there were HUGE concerns, beginning with the 09 TDI. One of the conclusions after quite a few (break in) UOA's 10,000 miles OCI's (VWA makes a HUGE deal of factory fill going a FULL 10,000 miles (break in) interval, were UOA's were ALMOST cookie cutter in wear metal results ZERO fuel dilution (was Winter's concern) . The longer term conclusion was (given use of the correct VW507.00) 1. dont bother with any UOA's till 30,000 miles to 60,000 miles 2. and do those as BASELINES.
Sidebar was 30,000 miles was recommended if one had engine warranty demand concerns as the BIG warranty is more like 3 years and or 36,000 miles.
#4441 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [rdub7]
Jan 06, 2011 (10:18 am)
I have to take issue with what is said here in that VW has had a problem setting standards for the motor oil. I have always found that VW oil standards are a constantly moving target that even VW cannot seem hit.
Oil analysis is all fine and good but using 60K miles driven as a baseline reading is senseless. Beyond 60K miles is the issue and as injectors wear, they do not work as efficiently as when they were younger so they may not close as quickly or they could leak and since there is an extra spray of fuel during the exhaust cycle during DPF regeneration that means, depending on driving habits, faster injector wear/break down. Oil change intervals are an issue too. I feel that 5K is about as long as one should good on a crankcase full of oil be it gas or diesel and even if the oil is a synthetic.
#4442 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [winter2]
Jan 06, 2011 (10:51 am)
I would not disagree with your take about VW setting standards and then having their own representatives (i.e.,VWA dealers) not fulfilling them.
Oil analysis is really the sum total, if you will of all those things you mentioned in effect MANIFESTING itself in the oil ! Ergo that is the real reason for the analysis. There is really NO question that all those things you mentioned and more are happening. Measurement and/or the analysis is really done to confirm (in effect) the RATE of engine degradation (slo mo of course) and whether or not your (developed for FLEET) maintenance schedules make (normally) economic sense. The other truth is even as lower OCI's (under 15,000 miles) yield much more aggressive wear metals and really induce a higher detergency state, statistically anything from 1,000 to 30,000 miles OCI's are just fine !!
So if they are, it really begs the question why change AT 1,000 to say your 5,000 when 30,000 miles will do?? The operative reality is something like why change 30,000 miles when 1,000 to say your 5,000 miles OCI will do !!!
#4443 of 4777 CPU Chip Modification
Jan 08, 2011 (11:29 am)
This guy I work with had his '04 Jetta TDI chipped and said he gained 35 HP and boosted his mpg to 62 . His turbo is always at 5 PSI and experiences no turbo lag when he needs it. If you've had your '09, or newer, TDI chipped, please let me know who provided the chip, how much it cost and what results you acheived.
#4444 of 4777 Re: CPU Chip Modification [rrollntdi]
by MrShift@Edmunds HOST
Jan 08, 2011 (11:48 am)
You'd want to do a whole lotta research before you believed claims like that. It's really a question of investigating the engineering of the "chip" or "reflash" to see what it's actually doing to the engine. Also there are "power boxes" which are easier to deal with. I'm personally not fond of chips that are "interfere" and trick the ECU---these strike me as rudimentary and perhaps harmful.
As for horsepower claims, unless they show you a dyno slip, they got nothin'.
#4445 of 4777 Re: CPU Chip Modification [Mr_Shiftright]
Jan 09, 2011 (3:21 pm)
Mr_Shiftright, thank you for your reply. I'm skeptical of the claims that my coworker made and will question him further. I'm also not sure the reflash would be safe for the newer engines. They all claim to be, but who really knows when it comes to a real engine problem. Maybe others have ventured into this technology and can report.
#4446 of 4777 Re: Learned something interesting about the new TDI engine (2009+) [rdub7]
Jan 11, 2011 (6:33 am)
I must disagree with part of what you say in your reply. OCI's are developed under ideal driving conditions with ideal fuel. Diesel fuel in the United States borders on swill and is high in aromatic compounds that produce more particulate matter. Also, the cetane rating is in the low to mid-40's. EU diesel is a higher quality fuel with far less aromatic compounds and a cetane rating of 51 or 52.
The OCI's proposed by VW and other EU diesel makers are based on EU diesel fuel and not our domestic swill.
I also take issue with your comments concerning detergency and I have a good example to give you. My wife drives a 1998 Chrysler with the 2.7L V-6. This engine along with several VW engines are known sludge producers. The timing chain tension is controlled by oil pressure and any iota of dirt in this tensioning system produces catastrophic results. I have been using a good high detergent synthetic oil in the engine for most of its life (Amsoil 10W-30) with an OCI of 3500 miles. I have done two oil analysis and no metal residue found in the spent oil. The oil pan gasket was replaced recently and the was absolutely no sludge, varnish, etc. found. Passages were examined with a fiberoptic device and found to be factory clean after 65K miles. The car sees city driving 90% of the time.
The crankcase in any diesel is a very dirty environment compared to gassers. The VW diesel holds barely five quarts of oil which is simply not enough for such a long OCI. Mercedes Benz 3.0L V-6 diesel holds ten + quarts. It is one-third larger than the VW diesel and holds 100% more oil. That makes more sense to me.