Guest Veritas
Causes and effects of sludge go a lot farther than some suggest, in spite of frequent inferences by a few individuals that an as yet unproven flaw exists which relates to oil change intervals, or their insistence that engines are being properly maintained and still sludging.
There have even been allegations (By one or two more vocal spokespersons) that engines are sludging with as low as 3000 mile intervals--although although in fairness, there haven't been any hard numbers or any pertinent details shown to date.
Looking at that one factor alone is an acute case of "chronic tunnel vision",(We often get this in the ongoing crusade of misinformation by a few individuals here which always points blame at only one thing).
Oil change intervals are only a small part of a much larger "proper maintenance" equation.
At 3000 miles after an oil change, any auto engine is beyond the point where oil levels are going to start to shrink.
At this stage, especially under "average" driving conditions, the process of oil consumption is well under way.
Oil usage in an auto engine is a fact of life. If an engine isn't using oil to some degree, it isn't getting properly lubricated.
If an owner chooses to go beyond that "start to shrink" point in oil change intervals, then that owner had better start checking oil levels routinely.
This becomes extra critical if the owner opts to go to the longer intervals being suggested by many automakers these days, i.e., 7500 miles or more.
Letting oil levels go unchecked at these higher mileage intervals is an invitation to trouble, no matter what make or model of vehicle it is.
With today's oil formulations, especially the synthetics, the oil in your engine can handily cope with longer intervals.
If oil levels are maintained properly, your car's engine can also cope very nicely with extended drain intervals. (Even Toyota engines can, in spite of efforts by a few to suggest otherwise!)
However, if owners don't check and maintain oil levels with these longer intervals, it's not surprising that trouble happens.
Under these conditions, regardless of who made the car, there will be two categories of owners--the first will be those who have already had trouble, and the second being those who will eventually have trouble.
Just about every tale of woe we see and hear about re this sludge propaganda makes a big deal of "I maintained my car by the book, I changed my oil religiously, etc.,etc."
Then the finger pointing starts "See, that shows the Toyota engines are flawed,etc.,etc."
What we seldom, if ever, hear is how frequently the owner looked at oil levels and topped them up if required.
In fact, a case which was discussed here not too long ago started out with the "I got sludge, I went by the book on oil changes, and because I did so, Toyota should buy me a new engine"
And the "hate Toyota" faction had a field day with every accusation they could muster.
However, after some close and astute examination, it was determined that the owner NEVER checked oil levels between changes. The owner admitted to this habitual flaw in how he used his vehicle.
We often see the term " I maintained my car religiously" when an alledged sludge incident is reported.
"Maintained Religiously" means a whole lot more than oil change intervals.
Sludge development is a PROCESS, not an EVENT!!!
People who truly "Maintain their vehicles Religiously", a.k.a., among other things, check their oil regularly, aren't the ones who are going to have problems like sludge.
I invite comment.