biglatka said:
I believe it's 5k miles between oil changes, at least for the 4th generation 4Runner. I've seen that link, thanks for it anyway.
The 7.5k Toyota recommendation comes from this very good oil thread:
http://www.toyota-4runner.org/showthread.php?s=&threadid=674
(Quotes from Thai and others)
The oil forum:
http://theoildrop.server101.com/ubb/ultimatebb.php
Read some here on Mobil 1:
Not the be all, end all but informative. Take it as you will:
http://neptune.spacebears.com/cars/stories/oil-life.html
from the site:
*Engine wear actually decreases as oil ages. This has also been substantiated in testing conducted by Ford Motor Co. and ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119. What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it.
* Topping up the crankcase is a critical component of extended oil change intervals, and frequent filter changes are most likely the key to extreme-length intervals. The cumulative effect of even minor top-ups, let alone a filter change, substantially increases the longevity of the oil.
*One thing we're pretty sure about though: 3,000-mile intervals is a huge waste of resources.
*To date we have completed our test of Mobil 1. It held on for 18,000 miles, and didn't need its first oil filter until 12,000 miles
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I ran ~7500 miles on my last oil change with Valvoline Synthetic and sent the oil off for analysis. It came back showing that I had almost no particles or contaminants in the oil. The oil was still protecting the engine even after 10% of towing at least 5,000lbs during that oil change at high speeds (80mph)...
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This was posted by me a while back:
http://neptune.spacebears.com/cars/stories/mobil1.html
Their conclusion is similar to what I recommend:
"Based on the results we've got here, we'd recommend 8,000 miles between oil changes on an engine that uses no oil at all, perhaps 10,000 miles on an engine that uses some oil, and 15,000 miles or beyond with a filter change every 5,000 miles. This, of course, isn't any kind of guarantee, and you must evaluate for yourself what your engine requires. One thing we're pretty sure about though: 3,000-mile intervals is a huge waste of resources."
Basically, if your engine burns oil, then you have to TOP IT OFF, but do not have to change the oil. Topping off will keep fresh oil additives coming into the engine. You have to change the oil filter often to keep the oil clean (get rid of the crud and metal shavings in the oil).
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