I am ashamed at the way car manufacturers take such unfair advantage of the gullible public, and feel it is high time the underhanded practice of lengthy change intervals was exposed.
It has been my experience that many franchised dealer workshop foremen and managers constantly remark on the premature failures they have to resolve, failures that they deem are indirectly caused by the extended change/service intervals.
There is no real evidence to support the idea that long service intervals are beneficial to the engines.
Considering that engines these days are far superior to their counterparts of 20 years ago, and are made from far better materials with vastly superior engineering, we should expect them to last a lot longer than engines from earlier days. My company recently decided not to replace a Mercedes Vito with a newer model.
The Mercedes salesman could not understand why we were disgusted with his proud statement that the oil change interval had been increased and was now 30 000 km – on a four cylinder commercial diesel.
Why are car manufacturers recommending the same oil change intervals for passenger and commercial vehicles using the same engine (such as a Mercedes Vito) when it is blatantly obvious that the hours of use between change intervals are hugely different? (Shortened)
JOE O’CARROLL – Kenilworth
Joe O’Carroll has been active in the motor trade for a long time, so his opinion carries a lot of weight.
The subject of oil change intervals and oil quality has become topical since Volkswagen SA decided that all its engines, even those in the lowly CitiGolf, have to be filled with very expensive synthetic oil. (see Technimail, November 2009)
There are tremendous pressures on engine manufacturers to increase oil change intervals, not only to save dwindling oil supplies, but also to reduce motoring costs.
Modern mineral oils are a lot better than they were 10 years ago, and synthetics are in a league of their own when it comes to combating sludge.
In mitigation we would like to say that the oil monitoring system used by Mercedes-Benz is similar to that used by many other brands.
For example, GM has discovered that during freeway driving, high-load service and city driving the oil degradation is caused mainly by high oil temperatures, but during extreme short-term driving water condensation and other contaminants are the main cause of oil degradation, because the oil never gets hot enough.
Most oil monitors therefore log the prevalence of these stressful conditions. The system used by Mercedes-Benz as well as some other manufacturers goes one step further and tests the oil’s resistance to electrical current flow from time to time, because this changes as the oil gets dirtier.
These manufacturers are obviously confident that the monitoring devices are working. Surely they would not damage their own reputation by persisting with a device that leads to engine failure.