oil changes: synthetic vs reg oil

[chevyeater]

Since I'm new to this diesel arena, I have a question about the duration of oil between changes.
1. how many miles between changing synthetic oil?
2. How many miles between changeing conventional oil?

I've been told by a reputable diesel mechanic, that syn lasts 20,000 miles. I"ve always changes my conv. oils at 3-5000 mile intervals. I always change out the filter at the same time.

I changed the conv. oil with Mobil 1 syn. last fall, and have about 7000 miles on it now. If I change it I'm switching back to conv. oil just because of the cost factor. Too damn expensive to run syn. I figure on runnin syn in the winter, since it was discussed on here that syn is better for winter start ups.

What's your opinion?

[ToMang07]

I am currently running Amsoil 15-40 CJ4 at 10,000 miles... for the cost of 2 dino oil changes. If you spend the money on an oil analysis for a company like Blackstone Labs, you can find out for sure whats going on in your engine/oil and exactly how far you can strech it.

Personally, I highly reccomend a good quality synthetic, and use blackstone to monitor your engine/oil health.

[late_99_PSD]

Originally Posted by ToMang07

I am currently running Amsoil 15-40 CJ4 at 10,000 miles... for the cost of 2 dino oil changes. If you spend the money on an oil analysis for a company like Blackstone Labs, you can find out for sure whats going on in your engine/oil and exactly how far you can strech it.

Personally, I highly reccomend a good quality synthetic, and use blackstone to monitor your engine/oil health.

X2. An oil anlysis is the only way to know for sure how long you can take an oil. But I would defininatly say at least 7.5k

[chevyeater]

so there is no set amount of miles that is recommended?
how do you obtain getting your oil tested?

[late_99_PSD]

There are many places that can anylize your oil, but a place like blackstone labratories (I believe they are in Indiana) knows their stuff and can set you up good. I'd give them a call. (simple google search should bring them up)

[h2odrx]

I use blackstone and love it, 22.50 for a test and you can log in and see the results.... the 22.50 was a dramastop special. I even got a call cause the saw some stuff they wanted more info on....