1999-2009 [Subscribe to Daily Digest] |
I'm quite aware of the numerous theories about how sludge came about; I read the articles in Nines magazine from half a decade back too, and I read articles on how and why sludge came about in Toyota, VW/Audi, and Chrysler cars of similar vintage. There are more than a dozen reasons involved:
1. fuel-saving light/low-profile pistons leading to blow-by combustion contamination;
2. turbo high temperature causing accelerated oil oxidation;
3. short driving pattern not fully warming up oil to above 212F causing water condensation to form sludge in oil without being baked off;
4. early PCV design (before #6) not adequate in providing the ventilation;
5. extended oil change interval depleting additives;
6. oil used by cheap oil change places not having the requisite additives to begin with; i.e. cheap SA oil instead of the up-to-date SL and SM oil;
7. oil used by even dealership in the early years of the model cycle may not have the high temperature tolerance that the turbo requires; i.e. semi-synthetic (which can be 10% syn in volume or less) vs. "full"-synthetic;
8. once formed, sludge can plasticize and form solids or turn acidic in the liquid form, which in turn attacks rubber engine seals and the PCV system leading to additional damage and solid debris landing in the oil; extended oil change duration exacerbate the problem
9. the small holes in the oil pickup screen can be plugged up by the debris and that would lead to oil starvation at the top of the engine.
Please do not assume others to be idiots. Please do not waste time arguing for turning the clock back by 9 years and spend the $35k on something else. A Toyota from that time would have similar sludge issues. That's 7 million Toyota's! Keep in mind however, only a tiny percentage (on the order of 0.5% - 5%) of engines among the "affected" models have actually died due to sludge. IMHO, with more and more carmakers turning to turbo and other fuel saving measures, and manufacturing tolerance getting tighter and tighter, the oil sludge issue may well increase with new generations of cars, not decreasing, unless car owners change oil more often and with the right kind of oils.
As for the problem being expensive and time consuming, it is free in the first 5 years of the car's life as it's covered under warranty; it can indeed be expensive and time consuming in the following half decade. Then at this point in time, 9+ years since I bought the car new, the solution can not be expensive or time consuming: for the simple reason that the car is not worth much and I can get a different car if it gets "expensive and time consuming" for any reason whatsoever. That's why let's focus on inexpensive and low-risk solutions, and not waste time on hugely expensive solutions like tearing down the whole engine, and forget about impossible solutions like turning the clock back. For what it's worth, even knowing the sludge risk, I wouldn't have spent the $35k on any other new car. It has provided 9yrs of trouble-free service and still runs very smoothly today, despite a possibility of having sludge.
posted by 71.184.95...
, Tue, 3 Aug 2010 11:13:49
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