I have posted this in other forums. Who here is running synthetic oils on an extended oil change (10,000 miles, 20,000 miles, ect)???? I am thinking of changing to synthetic so I can extend my oil change intervals.

Thanks for any reply's, I always seem to get alot of feedback and good information here.

 

I run synthetic for its cold weather rating not for its extended change intervals. I still change it at 5000 miles. Only way to safely extend your change intervals is to install a bypass filter system and run synthetic oil. I personally don't like the idea of leaving the crud in the the oil circulating through my engine for 20,000 miles but some guys say the extra filters trap all the crud. If you decide to do it be sure to factor in the cost of the system and how long it will take to pay for it. With the price difference between the dino oil and synthetic oil and the extra filters it will take a quite a while to pay for the system.

 

runnin amsoil 15-40 heavy duty diesel oil and the dual bypass. i just get the oil anlysis and change it by that. got a few trucks with really high miles and i think thats part to due runnin the synthetic and bypass gear. ive got one truck thats got over 50k on it and blackstone says its good to go still...its nice not having 14 quarts of oil per truck to dispose of too. with the bypass it takes down 18quarts now. changin filters every 10k and getting oil anysis at the same. i just tore down a motor that had 600k miles on it and the bearings looked great....the pan was clean nothing in it no crud.

 

Wow, that's nice. I would have expected to at least see the tin worn away on the bearings.

 

kwik ill have the pics up here soon. the bearings on the ends the tin has a couple spots with a little wear through but not too much. they look great for the amount of miles on it. dang i forgot how heavy that dang crank is.....

 

The key to extended OCI's, as others have stated, is a bypass setup and regular UOA's.

Extended OCI's work well on trucks that see lots of highway miles as those are the easiest on oil.

BTW, you don't have to run synthetic to run extended OCI's as most will have you believe. Some will rush out and claim that Rotella T syn is the Holy Grail of synthetics when it is really nothing more than a dino on roids. It is simply called a synthetic due to a law suit that was filed a few years ago. By using that same lawsuit pigeon holing, Chevron Delo 400+ could technically be called a synthetic as well.

Back to the topic...

Extended OCI's tend not to work very well on trucks that see alot of stop-n-go short trips, or stop-n-go in cold climates. The reason being is that even though most of the contaminates are filtered out, there tends to be a high concentration of moisture and fuel that never gets burned off as the oil never reaches that magic 180F+ mark for long enough periods.

If your truck is still covered by warranty, you may want to rethink the whole extended OCI bypass thing, as most dealerships are getting to the point of denying warranty work due to ANY modification, regardless of if it caused the failure or not.

I realize that it is "legal" to mod your truck due to the Moss act, but it could cause you a whole pile of legal costs and headaches. I'm not saying it will, but just forewarning you.

If you are running extended OCI's, even with a bypass, and you do have a oil related failure on your warrantied motor, you will be footing the bill to repair on most ocasions regardless of how many good UOA's you provide.

 

That's great. Curious, did you tear it down just because you were getting worried about it or was there a problem?