Oil

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jkslvr
Posts: 41
Joined: Wed May 07, 2008 11:03 pm
Location: Colorado

Oil

Post by jkslvr »

Will semi syn oil ruin the seals?
Twin Pinzies
Posts: 545
Joined: Mon Jan 03, 2005 1:33 pm
Location: San Juan Mountains, CO

Post by Twin Pinzies »

Unless you just rebuilt the engine stick with conventional. Suddenly putting synthetic into a 35 yr old truck that was built for SAE 30 (that's not even multi-grade!) oil is a bad idea!
Mine started instantly leaking at the seals with synthetic. Also, the detergents in synthetic oil released a ton of built up sludge in the crankcase... seemed like a good idea at first but it's not good to suddenly "flush" all of it out all at once. I have a problem with my oil immediately turning thin and black after oil changes now due to the sludge release. Before using synthetic, my oil would remain amber-colored for hundreds of miles before gradually turning black. Now with the "sludge release" issue, my fresh oil only lasts a few days before turning black. I think that a couple more flushes with conventional oil (and new filters) will bring back the conventional oil characteristics that I once had. I have had to change my oil every month due to synthetic/sludge contamination.

This is of course a debatable topic.
jkslvr
Posts: 41
Joined: Wed May 07, 2008 11:03 pm
Location: Colorado

Post by jkslvr »

Thanks

I am getting it ready for the winter this year.

10W40?
20W50?

What oils are you all using? Winter?
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