Oil contamination in this context refers to the presence of small particles in the oil itself.  This could include dust from a recent oil change or metal particles from previous engine trouble.  Most particle contaminants will be caught when passed through the oil filter.  However, if these small particles reach the turbo it can cause severe damage.

The turbocharger design on Volkswagen TDI engines does not use bearings.  Rather, the turbocharger shaft floats on a small film of oil that coats the inner race of the solid brass bearing.  A particle in that film will function as a piece of sandpaper and grind away the surface of the shaft and bearings.

Shaft! Can You Dig It?

The image above shows the grooved wear indicative of a particle caught between the bearing and the shaft.  The gold color of the left side worn areas comes from material transfer of the brass bearing.  The right side did not experience material transfer.

The outside material of the turbo shaft is often hardened, and therefore more durable than the inner metal.  Once a contaminant wears though the hardened surface failure occurs very quickly.

Groovy!

The same grooved pattern is seen on the inside of the bearing as well.  This wear widens the tolerance between the shaft and the bearing, allowing the turbine wheel to move latterly, this is more commonly referred to as “shaft play”.

Final turbocharger failure occurs when the turbine wheel itself contacts, or collides at high speed, with the housing.  The turbocharger housing will alter its shape when heated, and the grooved wear finally creates enough looseness that the wheel itself is unable to spin without contacting the heated turbocharger housing.

Maintaining proper turbocharger health in your Volkswagen TDI revolves around keeping to the maintenance schedule of 10,000 mile oil and filter changes.  If you live in or drive through dusty environments it may be worth considering switching to a shorter oil change interval.

505.00, 505.01, 507.00 – What do these mean?  10,000 mile oil change interval?  Really?  5W-40, 5W-30, 0W-30, which is better?

Driving a VW TDI means questioning and sometimes tossing out some long-held beliefs about oil and oil change intervals (OCI).  Pulling into your local quick-lube store and letting them put whatever’s in the drum below the floor into your car can be disastrous to your TDI.  We’re going to try to make it simple and help you choose the oil your TDI requires.

Why is Correct Oil so Important?

If you drive a TDI you already know it’s a remarkable engine.  Few, if any other engines offer a comparable combination of power, economy, and longevity.  However, several aspects of the TDI’s design make it hard on oil.

First, the TDI’s high compression puts its piston rings very close to the point of combustion.  Engineers soon learned that conventional oils could leave deposits, or coke, on the piston rings, which would jeopardize their function, increasing oil consumption.

Second, Oil is the life blood of a turbocharger.  If oil cokes or gathers residue then it can clog the turbo oil feed line, starving the turbo of oil and ending its life.  Not a good thing.

Third, newer TDIs (‘04 and later) have injection systems that are generate very high fuel injection pressures but are also hard on camshafts.  These cars require oil that can keep cam lobes lubricated in that high pressure environment.

Fourth, TDIs emissions systems have become much more sophisticated in recent years, requiring oils to be refined without components that can harm those systems.

Finally, all manufacturers are after maximum fuel economy and the longest possible oil change intervals in all their cars, and keeping oil in cars longer while providing the best possible fuel economy figures put additional demands on oils.

Oil Standards and Specifications

VW has established and tests oils to standards it has set for its engines.  There are several other industry standards for engine oils, but for simplicity we’ve stuck with VW’s standards here along with oil viscosity measures that are commonly used in the US.

Will oils that do not meet or include VW standards work in your TDI?  Probably.  Oils that meet other standards such as ACEA or API may be fine for your VW.  In fact, some owners purposely use oil that does not meet VW’s specifications because they believe it’s better for their TDIs than the ones VW certifies.   Just keep in mind that VW may ask for proof that your car has used only oil meeting their standards in the event of a warranty claim.

Synthetic versus Non-Synthetic

This distinction is not as simple as you may think.  Although all the oils that meet the standards in the chart above are considered synthetics, many of them may start with mineral oil base stocks, or esters.  You’ll see terms like “synthetic technology,” or “pure synthetic,” on labels.  But once again, if it meets the standard, it’s OK.  And in the world of TDIs, if it meets the standard it is going to be synthetic oil.

Diesel Versus Gasoline

There’s a simple point here: Diesel engine oils have different requirements because, in part, of the need to keep soot in suspension in the oil between changes.  You’ll notice that the oil in your TDI turns black very quickly after a change.  That doesn’t mean it’s dirty, it is keeping the soot the engine generates in suspension.  The presence of that soot is an oil design consideration.  There are many oils that meet both gasoline and diesel standards, but beware of oils that are designed only for gasoline engines, even if they are synthetic.

Match the Rating to Your Engine

The table below lists the TDIs sold in North America and years they were sold, the oil they require, and some (not all) of the oil brands that offer oils that meet the standard.

The brands listed here are not exhaustive, there are others.  And there are yet more oil brands that claim to be “designed for engines with 505.00 (or 505.01) oil requirements”, or words to that effect.  Just keep in mind that if the VW standard isn’t printed on the label, the oil probably hasn’t been certified by VW.  It’s your choice whether or not to use that oil.

What about 506.00?

VW has a 506.00 standard for oils that were considered good to use in cars that require 505.01 oils (PDs), and was also specified for the V-10 Touareg.  This was a 0W30 weight oil that helped improve fuel economy.  However, 506.00 oil was very expensive and did not match the lubrication or protective standards set by 505.01, and has been phased out.  The Lubro Moly Top Tech 4200, a higher 507.00 specification oil, is also specifically approved for vehicles requiring 506.00 and 506.01.

What about Weight?

Europe and America use multiple viscosity ratings for oils.  And there are a couple of trends in the oil industry when it comes to viscosity:

• Oil viscosity numbers are getting lower
• Lighter weight oils work better than they used to at high temperatures

Emissions and fuel economy requirements have, in many cases, driven manufacturers to use lighter weight oils.  Since EPA measures include a cold start, light weight oil helps cars perform better in that test.  Also, engine tolerances are much tighter than in past years.  Thinner oil (especially when cold) can help provide lubrication during those first few critical seconds after a cold start.  And today’s synthetics provide much better protection when hot than mineral-based oils did, even if their viscosity rating is lower.  For example, 5W30 weight oil is considered fine for all driving conditions in PD and Common Rail TDIs, even in the desert in summer.

505.00 oils (for rotary pump TDIS) have the widest viscosity ratings of VW oils, and include 0W30 and 0W40.  Although 5W40 oil is most popular in this category, many owners in cold climates like using 0W30 or 0W40 in winter.

And both 5W30 and 5W40 oils are available for oils meeting the 505.01 standard (PDs).  Both are fine for use in all climates, although some owners prefer 5W40 over 5W30.

10,000 miles?  Really?

All TDIs have a 10,000 mile oil change interval (OCI) after break-in.  After generations of 3,000 mile OCIs many owners have difficulty accepting the 10,000 mile interval as safe.  But 10,000 miles has proven to be a more than reasonable interval.  Many owners run their oil longer.  TDIs are proving to last many hundreds of thousands of miles without major wear using a 10,000 OCI with the correct oil, and many feel it’s wasteful to change it more often.

Soot build up is the primary reason for oil breakdown in diesels.  As oil advances further technologically the different specifications have been increasingly tolerant of high soot levels in the oil.  This results in many european vehicles with flexible service intervals to go 30,000 miles or more between oil changes.

Summary

Simple enough.  If your car:

• Has a rotary injection pump, use oil that meets VW’s 505.00 standard
• Is a PD, use oil that meets VW’s 505.01 standard
• Is a Common Rail, use oil that meets VW’s 507.00 standard

Diesel on!

VW has sold a lot of platforms and generations here, but only a few with TDIs. Here’s a guide to the platforms and engines in VW TDIs in North America. There are two basic engine types, rotary pump and PD (Pumpe Deuse). The engine codes for each platform are also listed below.

VW A3 Platform

Models:

• Jetta TDI in model years 1997, 1998, and first half of 1999.

These are all rotary pump cars, mostly with engine code AHU. Some early A3s (1997 only) have a very similar engine with the code 1Z. With the exception of some internal engine parts the AHU and 1Z engine components are interchangeable. All have manual transmissions.

VW A4 Platform

Models:

• Jetta sedan TDI from model year 1999.5 through the first half of 2005
• New Beetle from 1998 to 2006
• Jetta Wagon TDI from 2002 to 2005 (2006 in Canada)
• Golf TDI from 1999.5 through 2006.

All A4 models switched to Pumpe Deuse (PD) engines from model year 2004 on.

Engine Codes:

• 1999.5-2003: Rotary engine code ALH
  2004-2005 Jetta, 2004-2006 Golf and New Beetle, Pumpe Deuse engine code BEW.

VW A5 Plaform

Models:

• Jetta sedan from 2005.5 through model year 2009.

The A5 was produced in 2005 and 2006, had a special including special ‘diesel’ edition Jetta in late 2006. Some of these cars are actually 2007 model year cars sold as 2006s. The 2005.5 and 2006 cars all have Pumpe Deuse engines with code BRM. There were no TDIs sold in the US in model years 2007 or 2008. The 2009 “Clean Diesel” is a Common Rail engine with code CBEA.

VW B4 Platform

Models:

• Passat TDI sedan and wagon, model years 1996 and 1997.

All B4 Passats have engine code 1Z.  These were the first TDIs sold in the US. These cars also all have manual transmissions.

VW B5.5 Platform

Models:

• Passat TDI sedan and wagon, model years 2004 and 2005.

The B5 Passat was sold from 1998-2001. The B5.5 was introduced in 2001.5, but didn’t have a diesel in the US until 2004. All B5.5 Passats have a 2.0 liter Pumpe Deuse engine with code BHW. All are automatics.