A question about using extended oils...my feeling..

Stay within factory max intervals during waranty. Then switch if you like.

You can run out as long as you can. On commercial vehicles we can take their intervals from 100 hours up to 600 or even 1000 with oil analysis..

As far as miles go the guys on Bob's board who extend with Amsoil or M-1 EP chicken out at around 18,000 miles. That's with oil filter changes and topping off in between every 5,000 miles. The whole process may save oil but when you add up the cost of doing tests to be sure and the oil filters and topping off.

I say just go the manufacturer's maximum and then change.



My .02

You can run M-1 out too 25,000 miles and Delvac 1 out to 30,000 miles. They will be coming out with a 1.8million mile ad here soon. If you are using Mobil. I would use the Signum Oil analysis. It gives trend analysis. Blackstone only gives a snapshot. I would follow the manufactures oil recommendations. I though have seen the tests, seen the oil analysis's and the engines after a million miles that look brand new.

The day an oil company teams up with automakers and they both concur and assure me that that going 25,000 miles on any oil will retain the manufacturer's engine warranty will be the day I change my mind.

The commercial OEM's will warranty it... Mobil 1 used to have guarantee's for the 25,000 miles and that's how it was marketed in the early 80's. Granted I was in my diapers, we still have the sales materials. I'd have to look but I think one of them that is initial filled says you can go 15K with a filter every 5K. ?? I'd have to look.

...just have 'em put it in writing in my automobile warranty book please..

If you get the warranty from Mobil... They will purchase you a new engine if it was due to oil failure. Never once happened. There are Comercial Warrinties for the Delvac 1 and 1300 Super and PVL for the Mobil 1.

They are certificates car dealers hand out and so on

I think going "extended" needs to take factors into consideration such as how clean burning the engine is and what metals the components are made of. There is no "one shoe fits all sizes here"...

For example Porsche' states the following:

"Patented LOKASIL high-silicon cylinder liners help reduce friction and wear to such a level that Porsche can recommend a 15,000-mile (24,000 km) oil change interval and a 30,000-mile (48,000 km) oil filter change interval".

Briggs and Stratton is using Teflon coated pistons; better trapping oil filters and synthetic oils for extended use.

So I think extending is part the oil's role and part the manufacturer's role in engine metallurgy and coatings etc.

For marine engines as we know the premium Synthetics hold up better under adverse conditions such as when condensation accumulates and when gasoline may contaminate the oil... this alone can save an engine. Offshore cast iron hogs still need relatively frequent changes much depending on use and environment. So using a Premium Synthetic extends the engine's life most importantly.

I received several e-mails about non-premium synthetic multi-vis oils such as Mobil-1 15W-50 Goldcap or other $5-6/qt synthetic oils from Amsoil or Quaker State etc. in reference to use in offshore boats.

I am surprised the question still keeps arising but here is my current feeling and it is an opinion. Here goes:

-For what I call "recreational offshore boating"... with a non-blower or non-hopped up mill... where the engines are in the cruise mode for much of the time with a good run in-between....the $5-6/qt synthetics are fine.

-For added protection if your engines are blown; hopped up and you live at WOT and don't know what "cruise" is all about...then you ought be into a Premium Synthetic and they cost $7-9/qt. Yea like 20W-50 V-Twin..Amsoil 20W-50 Racing etc.

The Premium synthetics mix with gasoline and still retain film strength for you blower or hopped up engine folks...and they handle heat and shear much better. They are the racers edge.

So pick which suites your needs if you are a synthetic person.