Factory Recommendations: Which is Right?
by Richard Widman

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This paper is basically a translation of my root cause investigation of some engine failures and my discovery of problems with oil flow in cold weather. I did not intend to publish an English version, but after a lot of searching I found that very little has been published on the subject of used oil flow in cold weather. Less yet about what I discovered: The vehicle manufacturer was not following the recommendations of the engine manufacturer!

I was encouraged to put it into English by many people who have written to express their thanks for my articles on engine oil for flat tappet engines and the difference between GL-4 and GL-5 gear oils in synchronized transmissions.

This paper was originally published in Spanish as my Maintenance Bulletin #85 at the end of August 2010 to several thousand subscribers and posted on www.widman.biz

The premise
When we buy a vehicle or piece of equipment we should consider the maintenance recommendations of the manufacturer. The key word here is “consider”. En my root cause study this month of the failure of several Cummins engines I found that the recommendations of Volkswagen for the maintenance of the Cummins engines in their trucks did not coincide with the recommendations of Cummins for those engines. This resulted in the catastrophic failure of several engines. In this paper I will detail the root cause analysis.

Problem identification
This month a company that had four trucks equipped to pick up and compact trash in the city contacted me. In the cold they were having troubles with noises on startup and one engine had seized. I immediately went to investigate.
As I have indicated in many previous bulletins, the first step in a root cause analysis is collect all of the information possible that might relate to the issue.

Pertinent data
  • The four trucks are Volkswagen 17-220 units and were bought new.
  • All four trucks had been in service for 3 years, accumulating between 14,000 miles and 33,000 miles in 2400 to 5600 hours of use.
  • The ambient temperature at the time had warmed up to 32℉ (0℃) from a low of 14℉ (-10℃) by the time I got there.
  • The oil in the filter had the appearance of black gelatin.
  • A visual inspection of the three trucks that had started did not show excessive soot in the exhaust.
  • The truck with the seized engine had 29,000 miles (48,000 km) and had accumulated 5175 hours since new. The oil had been in use for 4970 miles (8000 km) during 860 hours of trash collecting.
  • The engine is a Cummins 6CTAA 8.3 Euro II
  • The filters are “original” from Fleetguard.
  • The oil is a Group II API certified CI-4 SAE 15W-40. When new it has a pour point of -20℉ (-29℃). It is in use in thousands of other trucks.

This is the point where a lot of people stop their analysis and simply change brands of oil. With 20 different brands in the market, you can go through a lot of engines before finding the real problem. But in this case, the mechanic is good and wanted to find the real cause of the problem.

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