good point! Then, any idea why my modern 2,0l tdi engine running with full syn oil is burning a quart oil on 3000km?
Oyle So, being dumber than a flat rock I now asume that this sludge build up comes from the old regular dinosaur and compost motoroil????????? Which comes back to what I've been told and learned along the way. Use a good name brand regular motoroil and the engine will remain reasonably clean. It's the cold starts and short runs that kill an engine plus some oils just naturally sludge more. I learned that with a popular brand that I used for years simple because I also used the same filling station and brands my parents used. Once I stopped using that oil, famous for sea shells, my engines actually cleaned themselves of much of the foam and sludge. For years I used oil from Pa. Your usage may vary!
I never used Pennsy-grade oils in any car I owned because of the high paraffin content, which carbons very easily. Shell oils had that problem to a slightly lesser degree, in addition to the lack of detergent, causing foaming. But nowadays, the EPA mandates base stock cleanliness and since some base stocks from various oil regions are too expensive to clean, new types of base stocks from other than mineral oils are coming onto market. Pennzoil advertises a new oil where the base stock is synthesized from natural gas, which would guarantee high purity, but then how many additives go into it to give it the same properties as mineral oil?
It was Shell that used to cause the foaming and sludge. Like written oil has changed so that problem may be cured.
I used this for my last oil change in the wagon http://www.valvoline.com/products/consumer-products/motor-oil/racing-motor-oil/6