Synthetic oil used after Natural oil

[Hunter66]

The reason, I was told if you have high milage, synth can wash out carbon in the cylinders and cause lower compression thus not leaking oil but loosing it past the rings. I switched at 80K and I cant keep the oil at the full mark for more than a week or two, but it will hang at the 3/4 mark for weeks on end, I have no idea why.

oils today have detergents both kinds.I think it helps alot. I use Mobil 1 and I go 6,7,8K on an oil change.

Just a little story, TRUE by the way. Years ago I used Amsoil allthe time it was the only Syn on the market that stated a 25K oil change NOT the filter just the oil.My buddy ran a change to 28K then sent 4 oz of the oil to an oil analysis lab in South Jersey. they sent back his results. They said he wasted his $$$$ changing his oil it still fit the specs for new oil. Yes it was still dirty, he used Amsoil filter changed out every 6 to7K. It changed the way I see oil.

One more tid bit. I know a guys who used a dual remote (1 qt filters) under the hood and he never changed his oil per say. Once every other month he spun a new filter on and added 1qt THAT WAS HIS OIL CHANGE. he used Mobil 1 and only ever had the drain plug out once, he sold the Dodge Ramcharger with just over 300K on it.

 

[j-rad]

That is true----

The reason, I was told if you have high milage, synth can wash out carbon in the cylinders and cause lower compression thus not leaking oil but loosing it past the rings. I switched at 80K and I cant keep the oil at the full mark for more than a week or two, but it will hang at the 3/4 mark for weeks on end, I have no idea why.

oils today have detergents both kinds.I think it helps alot. I use Mobil 1 and I go 6,7,8K on an oil change.

Just a little story, TRUE by the way. Years ago I used Amsoil allthe time it was the only Syn on the market that stated a 25K oil change NOT the filter just the oil.My buddy ran a change to 28K then sent 4 oz of the oil to an oil analysis lab in South Jersey. they sent back his results. They said he wasted his $$$$ changing his oil it still fit the specs for new oil. Yes it was still dirty, he used Amsoil filter changed out every 6 to7K. It changed the way I see oil.

One more tid bit. I know a guys who used a dual remote (1 qt filters) under the hood and he never changed his oil per say. Once every other month he spun a new filter on and added 1qt THAT WAS HIS OIL CHANGE. he used Mobil 1 and only ever had the drain plug out once, he sold the Dodge Ramcharger with just over 300K on it.

My brother works at a trucking company that has 400 trucks and company cars. They do all their own maintenance and they did a long term study including oil analysis to see how they could lower costs and repairs. They found that if they use synthetic (they found that mobil 1, shell rotella are almost identical), the best filters, inlcuding a second inline filter on the big rigs, they could go 50,000 miles between changes. The cars would go 15,000 with 2 oil filter changes and top offs.
I did an oil analysis on my 01 sport at 95000 miles with 4000 miles on Mobil 1, and Brownstone said that I can easily extend changing intervals. The syn was basically 97% of what it was when I put it in. Syn really works for extended change intervals, but you have to use good filters. Fram sucks. Bosch is much better. There are others that good as well.
Here is a great oil article link: http://motorcycleinfo.calsci.com/Oils1.html

I have several bikes so that is why the article is somewhat geared toward motorcycles.