Date:         Wed, 13 Jan 2010 00:13:55 -0500
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: Motor Oil (Synthetic)
In-Reply-To:  <0f0501ca93da$a3225410$e966fc30$@net>
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I have been getting somewhat amused by all this oil stuff. The miss information, etc is becoming too much to bear. I am going to make an attempt to simplify things and give some useful information. I have many years experience not only with automobile stuff but industrial engines, motors, gearboxes, compressors, etc. I started working on VW's at 14 (now 49) and remember all the lubricant failures of the 70's and 80's. The best was often known as the "Black Death" where so much carbon and sludge would form in an engine removing the valve covers revealed carbon troughs were the rockers moved and the oil galleys would be clogged solid. We now bitch when a water boxer needs head gaskets but I remember the days most cars did not go 100,000 miles due to rust, engine or transmission failures. As a kid we frequently traveled from Islip Long Island to Brooklyn to visit grandparents and it was common occurrence to cars broken down on the "Belt" Parkway. We are now somewhat spoiled. Oh and let's look at web postings of oil performance based on 1991 information. 

The most important consideration for oil selection is viscosity. Back in the old days there were no multi-weights. Oil had to be seasonally selected. SAE 30 was the popular compromise for most cars. 10 or 20 in really cold climates but no extended highway use for that. Tropical got the SAE 40. SAE 50 or 60 was specialty or race stuff. 
Later engines though had a major problem. The oil would get just as hot with little regard to outside temperatures. We need oil that could flow at the lowest prevailing temperatures yet maintain viscosity at full operating temperature. Viscosity index improvers and multi-weight oils to the rescue. This did not work as well as planned as first. One difficulty was the waxes present in most of those oils. As temperatures dropped, at some point the waxes would congeal and separate out and regardless of design viscosity. No starts or engine damage was the result. So here is the first major advantage of synthetic oils. Improved viscosity range cold weather performance. Of course modern conventional oils have also come a long way. 

For our Vanagons proper oil viscosity is the number one priority. As compared to most modern engines higher viscosity is required for a number of reasons. Both the owner's manual and the Bentley have the viscosity charts in them and these requirements really have not changed. Available choices have. For the most part SAE 20w-50 is the preferred choice for most normal temperatures. The chart does shoe that for tropical use a straight 40 is preferred. Back then a straight 40 would hold a higher viscosity than the 20w-50. With current oils I would stay with the 20w-50. As for synthetics some of the equivalents use slightly different numbers. For example Mobil 1 is a 15w-50. 
Now for these ratings it should be noted how the ratings work. The first number or "W" rating is the oils viscosity at 40C, (104F), and the higher number is the viscosity at 100C, (212F). This alone does not tell you what you have at -20C or 150C. These are the extremes where the synthetics again shine. 

Now, why does the Waterboxer, (WB), need special attention to this? There are two things that occur in this engine that do not normally happen in most modern engines. The first is mechanical tolerances. The WB just like the older air cooled engines is really a very sloppy loose fitting engine, especially the bearing clearances. As the engine warms up the clearances increase further and the pump has limited reserve capacity to keep up. The pump also loses its ability to pump as the housing and case expand faster that the gears. The problem gets worse as the case expands around the bearings and you get more internal leakage there. Now while this is happening we have another enemy, oil temperature. During extended high speed high load operation the oil heats up and can get hotter than the coolant. Remember that not only is the oil getting heat form the bearings and being pumped it is picking up heat form the pistons. The oil can easily get much hotter than the coolant. So as the oil gets hotter we lose pressure. As we lose pressure in the bearing, the oil gets hotter still until at some point we have a thermal run away. On the 2.1L engines the oil cooler was added to help this and dynamic oil pressure warning system detects this. No a Mann or Mahle filter does not fix it. Especially since the sending switch for the buzzer is before the filter.  So we need the heavier oil. And oil level is also extremely important here. DO NOT OVERFILL! Between the marks is good. The top mark is not the full mark. It is the maximum do not exceed no matter what mark.  

So what about winter? For the most part conventional 20w-50 oil is only suitable down to about -7C, (20F). Below that engine starting can become difficult. Even if starting is not an issue you need to be real careful here. The oil pressure relief does not handle this extreme well. Allow warm up time and keep the revs down until the engine gets some heat. Some real damage can occur here. Excessive oil pressure can blow out the oil filter gasket, oil cooler seal and oil cooler itself. I have seen the oil pressure galley plugs blown out and the drive tab on the oil pump shaft sheared off. If the oil is cold and thick enough the bearing shells can actually try to lock to the crankshaft and turn with it. This is known as a "Spun" bearing. The spin may not be a problem right away. The rod bearings can also fail this way but we will tell ourselves that it was the stretch bolts that caused the failure.   

So what do we do for winter? If using conventional oils you need to go down to 10w-40 or even a 5w-30 depending on how cold it can get where you live. I would not recommend any long high speed trips on the 5w-30. If using synthetics Castrol offers a 5w-40 and Mobil 1 offers the 0w-40 European Formulae. I run my Fox, 600SEL Benz and Audi A8 on this oil year round. Great stuff. The Mobil 1 15w-50 is also good for intermittent cold weather use should have no problem down to about -15C. Castrol also offers a 5w-50 Syntec that should be good for almost any temperature. 

It is interesting to note that while most American and Asian manufacturers are calling for low viscosity oils such as 5w-20 or even 0w-12 the European manufacturers are not. My son's 2009 Jetta calls for 5w-40.  

Now what type of oil should I use? This is becoming a real challenge now. There are so many choices and more manufacturer specific stuff is regularly arriving. The Mobil 1 market place alone is amazing and a lot of oils are becoming available through dealers only. Basically though next to viscosity is the API classifications. The oldest labeling the S?/C? designations. The "S" refers to spark ignition (gasoline), and the "C" refers to compression ignition, (Diesel) engines. If you go into the industrial world you also have spark ignition oils for natural and propane gas engines. The Diesel engine world has become more perverse that the gas world but I will stick mostly with our Vanagons. SM (2004) is currently the latest gasoline engine oil. Any of these oils will do a great job including some of the benefits of synthetics. Other classifications relate to fuel economy and some other manufacturer specific specifications. For Diesel oils CJ-4 is now the latest. 

Now a number of folks have suggested using the diesel oils thinker are real heavy duty lubricants with all the zinc or whatever a Vanagon needs. 
C rated Diesel lubricants are specialty lubricants that are designed to address certain requirements of Diesel engines. In particular they need to control and keep soot in suspension and from before 2007 they need to neutralize sulfuric acid, (the result of Diesel sulfur, heat and moisture). Problems gasoline engines should not have. Now the additives that are needed to do this can foul oxygen sensors and catalytic converters. These oils really do not belong in modern gas engines. Now since 2007 and later truck Diesels have exhaust after treatment devices these oils have been reformulated. The difference between CI and the new CJ-4 rated diesel oils. The synthetic versions of these oils will now usually have the gasoline engine ratings so they can be used in mixed fleets.   

Do note that most of the 20w-50 oils and especially the Mobil 1 15w-50 are still relatively high zinc formulations and will protect and flat tappet engine of the 70's and 80's no problem. There is some detail on the Mobil 1 site. 

How often do I need to change my oil? To really answer this question you need to do some oil analysis. There are many variables. The Vanagon owner's manual indicated that for both conventional and synthetic oil 7,500 miles is the limit for normal driving. With 254K on FUN BUS and a few years of analysis this works for the Mobil 1 15w-50. My 1988 Fox can go as high as 14,000 miles with good filters,(not Mann or Mahle). The Vanagon oil tends to need replacing due to nitration, (high ring temps burning the oil). The fox needs changes based on silica and wear particles. The air filter placement obviously cleans the road. While oil analysis costs almost as much as an oil change it really is a good investment. You can often get good information and detect problems you do not know you have such as coolant getting into the oil or that the air filter has failed.    


I hope this is good info for some. For those that have more questions I will try to help. For me I am addicted to the Mobil 1. The FUNBUS gets the 15w-50 all year. Red van has had the 0w-40 in Winter, (daily driver). Both on 7,500 mile change intervals. The FOX, Audi A8, Benz get the 0w-40 all year. The fox gets oil testing at 5,000 miles or after nasty winter like we have now. And now looking at 10,000 mile oil changes, (was trying for 15,000). The Audi and Benz on 10,000 mile changes. The Motor home (Cat-C7) gets once a year or 15,000 miles if that come first. That gets 5 gallons of Mobil Delvac 1, oil testing every 5K. 

Dennis