Good evening all,
I had purchased a dual bypass set up for my 7.3. I ended up selling the truck before I installed it. I just gave the system to a friend who has a 7.3. For those of you running the amsoil system, what are your change intervals on the full flow and bypass filters. Additionally how many miles are you going between changes?
Thanks

 

I inherited one of those on an old X. The BP filter, if it is the Amsoil filter, is rated for up to 50K or every other oil change as long as you are running the Amsoil full flow extended interval filter and change it on time. For the full flow, it depends on which filter you run. Amsoil has one that is rated for up to 25K.

I did not like it due to the fact that, if you wanted to stay within a certain micron range for filtration, you had no other choice but to buy Amsoil filters due to diameter and thread count of the fitting.

Some of this may have changed so you could head over to Amsoil.com and check it out.

 

Tell your friend to change at 7500-10000 and sample the oil if he really wants to know. I have two 7.3's, one with the Amsoil bypass and one just an Amsoil full flow filter. I sample both through Blackstone and run Amsoil 15/40 heavy duty diesel/marine. The 7.3's shear oil due to the high pressure system and my samples come back basically the same on both trucks with recommendations not to run so high of mileage. There is also a noticeable difference in performance when I go to 10,000 miles then change oil.

 

I don't have the Amsoil system, but I AM running a bypass system from OilGuard (Racor components), and I've put about 140K miles on it in the past 8 years. Having done some early (5K miles), mid (10K miles), and late (18K miles) cycle testing, I settled on 18K cycles. The Baldwin main flow filters I am running hold tight for 8K miles, but then start leaking and it's a battle to keep them from leaking after 8K miles. Consequently, I change my main flow filter at about 8-9K miles at the middle of my OCI, and I change the bypass filter element when I change oil at about 18K miles.

 

UOAs are the best way to dial in an OCI, IMHO. They are not infallible by any means but they at least give you an idea of whats going on. I had a single bypass on my cummins in my old dodge and I ran the filter until it plugged. It is a bypass filter and I used a plugged port as the oil supply so if the filter plugs then it shouldn't effect anything. The last filter I had on the truck had 60k miles on it and was still flowing. I liked the single bypass cause it retained the factory filter location so the replacement filters where cheaper since I was only buying the Scamsoil bypass, not the more expensive full flow filter. I don't think I would be as aggressive on the dual bypass since all the oil in the truck has to go to the remote head, so oil changes will be very expensive since the amsoil bypass filter is not cheap.

 

I run an Amsoil bypass. I change my regular filter and oil at 15k and I change out the Amsoil filter every other change. The Amsoil filter is rated for 60k but I would not run it that long. As has already been stated, the Amsoil filters are rather expensive; however, I do not change mine very often so a few filters will last several years.

 

On those dual setups, the bypass filter is still just that, a bypass filter. The filters are plumbed in parallel. A small amount of oil flows thru the bypass filter because of a slight pressure drop across the full flow filter. It bypasses the full flow filter. All of the filtered oil is returned to the lube system instead of being dumped back to sump like the single units.

I run Amsoil 15w-40 Diesel Marine oil and sent oil samples to determine a safe change interval. I run 15k miles and change both filters but I could run the bypass longer.