1999-2009 [Subscribe to Daily Digest] |
Over the years the piston rings were moved up to reduce the space above the rings where trapped fuel did not burn properly. The rings run hotter and oil in the ring grooves is more prone to oxidation and coking. It is a chemical reaction and synthetic oils were developed to avoid things like this. What else has changed? FRG and RFG-II fuels may be partly to blame as well. Techron Concentrate removes carbon coke deposits from piston tops and cylinder heads, at least what you can see with a bore-scope. It would make a lot of sense to also have an expectation that it will also clean piston ring lands and free sticking rings.
The ring tension has been reduced to reduce friction, which makes stuck rings more possible and blow-by gases may be increased as well. The problems with the PCV system and crankcase pressures certainly are consistent with increased blow-by gases. The blow-by gas RFG-II partial combustion products might be quite reactive and responsible for promoting or forming sludge.
The biggest cause of sludge is neglect and some folks simply don't care or are ignorant. When changes are ignored, the high levels of wear metals will also act as catalysts. Metal compounds are added to some oil based paints where the drying process involves the oils oxidizing and cross linking to form solids... the same is happening in engine oils that sludge. When you have vege oils on baking dishes in the oven, the same happens and the varnish that results is very obvious and tough. Note that if you use a light coating of butter or animal fat instead, that these will not turn to varnish and this allows for a much easier clean up and effective non-stick treatment. The oil sprays such as the ones that contain olive oil are really dumb as these will turn to varnish in the oven, depending more or less on time and temperature. So the animal fat VS vege oil examples are a real good insight into oils that sludge VS not.
Short trips that allow for more condensation of moisture and the fact that the amount of unburnt or partially burnt fuel during warm up combine to create a hostile chemical environment. That is why oil change intervals must be shorter for city bound drivers with short trips.
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
