VW 3.0 TDI

[jmartin]

Starting this thread to document working on my VW 3.0 diesel. The experts on here may be able to weigh in now and then and keep me from doing something too stupid. Maybe there are others on here who own small automotive diesels who wish to maintain them properly and can benefit from such a discussion.

I picked up a very good deal on a 2012 VW Touareg TDI with 139k miles on it. The engine is the 225hp 3.0L CATA version with EGR/DPF/SCR.

Some reading material on this engine: 3.0 SSP

It runs and drives "fine" but of course suffers from "deferred maintenance" like every used euro vehicle here. The plan is to start with an EGR tune up and fix the minor issues found so far.

-No stored engine or emissions codes
-RPM/boost dependent turbo whistle
-Exhaust leak from engine bay at startup and standstill with engine running
-Slight RPM fluctuation at idle at times

The "turbo pulsation damper" seal (at turbo inlet) was leaking, as was at least one of the intercooler connections. I'm going through the intake system and replacing all the orings and seals which I hope will fix the turbo whistle. Turbo itself feels ok - I cannot feel any movement in the turbine bearing, either axial or radial. There is a significant amount of oil in the charge air piping - I drained a cup out of one of the intercoolers. Not sure if that's normal for these engines or if the oil separator has failed - no PCV on these.

Think I found the exhaust leak source - there is a crack in the EGR flex pipe coming from the turbo pedestal. What's interesting about this pipe is it contains a mini-DOC which is supposed to burn up soot before it gets into the intake. Unfortunately that little sucker is expensive - currently $600+ from VW. Seems they are known to crack, maybe due to the heat cycling caused by that catalyst. It doesn't look very fun to replace.

This engine has 4 timing chains located at the back of the engine. Chain stretch is a known issue on these, which I blame on the low-SAPS 5w50 or 5w30 oil spec on long intervals. Maybe there are other factors as well. Fortunately, it is easy to check chain wear via an adaptation value. Mine shows around +4.3 degrees (new engine would be at 0 deg). I'm told they can generally get to +7 before you need to start thinking about replacing them. There is zero chain rattle at startup. Obviously the goal is to slow the chain wear rate as much as is possible going forward, hence my comments in the "gear lube in engine oil" thread. Thinking I will either go with Rotella T6 (5w40 or 14w40) + 10% GL5, or Motul X-power 10W60. The Motul oil appears to be higher SAPS and most importantly can be purchased from a certain Euro parts supplier that offers lifetime warranty on everything they sell including engine oil - the savings can be substantial. You can do regular maintenance for the cost of return shipping the filters/oil etc back to them.

Enough for now... I will try to update here as I go through EGR tuneup and maintenance etc.