98v70dad wrote:I never asked for anyone's advice about what oil filter to buy. I asked how it is justified to use the same filters for dino oil and change them fairly frequently due to the change interval of 3000-4000 miles compared to synthetic oil changed much less frequently with a change interval of up to 15000 miles. That is the standard industry practice and it doesn't make sense.
The sled currently has a bit over 211,000 mi on her. I'm the original owner to boot. After much oil research over on BITOG, I now use M1 10W-30 HIGH MILEAGE, which runs very well, with very little oil consumption. I leave the synthetic oil in for about 10,000 mi, but change the oil filter (I too use Puralator) every 5,000. When the oil is changed, I also drain the oil cooler.
I might be able to go even longer, with an oil test, but haven't bothered. One thing I did learn is that just topping up the new filter with replacement oil, refreshes some of the additive package and detergents, even though the spin-on filters won't hold an entire quart. There is documention at BITOG to back this up.
Before one change, I used BG109 engine flush several years back, to remove some very dirty oil that reaked of gas when PCV system had an open vacuum line. You may want to use 109 to flush out as much dino oil as possible before going to 100% synthetic.
Yeah, I understand the frustration when you don't actually receive an answer to the question you asked! Very frustrating indeed!98v70dad wrote:Most responses were, use a good filter and then people indicated what they use. Maybe people haven't thought about the issue of a filter staying on the car twice as long with synthetic oil ... don't know.
