Let's talk about extended intervals

Patman

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I've been reading a ton of the old posts on the Edmunds board about extended intervals, and thought it would be a good topic on here, especially with the new SL rated oils out now. What oil change intervals do you guys feel are safe with these new SL rated dino oils? Are 5k intervals well within reach for most people now, since the SL rated dino oils contain the new Group II+ base oil? (they do all contain this now right?) So if a dino oil can go this long, what about an oil like Maxlife? It should be able to handle 6k then correct? And regarding the true synthetics with group IV and group V, what would their upper limit be? 15k? 20k? (I know Amsoil says 25-35k but I find that a bit extreme) And one last question, what about the oils that claim to be synthetic but use a Group 3 base oil instead? What kind of interval could they handle? I realize that each particular application would be different, depending on the vehicle used, climate and condition of the engine itself, so I'm basically looking for general ideas, and also thought this might spark some interesting conversation. I asked my father in law yesterday how often he changed his oil and he said 3mo or 3k, almost without fail. People are just so trained to think that way, even though oils are getting better and can definitely go the distance.
 
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Cordelia, CA
One thing I love about this Pavlovian response towards 3k intervals is that this has been the recommended interval for at least 30 years, probably longer. I really don't think my 300 HP LT-1 is any harder on oil than a 300 HP 350 from the early 70s. In fact, with the modern engine controls, I'd say it's easier, since it does not load the oil down with excess fuel. But oils have come a LONG way in the past 30 years. I'd say 5k is easily within the reach of a modern Group II based oil and 6-8k possible for group III, with certain caveats. Some engines are much harder on oil than others. As far as PAO based synthetics I'd say 10k is a good conservative limit for the 5W30s, others certainly being able to go 12-15k. Of course if your analysis is still coming out good at that point, then you can push it further.
 
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Clarksville, Tennessee
quote:
Originally posted by Patman: And regarding the true synthetics with group IV and group V, what would their upper limit be? 15k? 20k? (I know Amsoil says 25-35k but I find that a bit extreme)
Why do you find it hard to believe that 35,000 is extreme, you have to remember that is for 1 year also, if you are doing that type of driving, and changing your full flow(Amsoil) every 12500 it would be no problem to go that far, otherwise Amsoil would not advertise it!! I went over 18 months on my last oil change, granted it was only about 10K miles, but I have many short hops, as well as only one filter change should have been 3 at least, the oil was still good. Here is a pic of the side of my truck, You want to talk about Extreme!!! http://www.lube-direct.com/pictures/Truck_side.jpg
 

Patman

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I guess when I say I find that interval a bit extreme, it's more of a personal comfort level than anything else. I could be convinced if I saw some oil analysis data on cars that have run the full 35k interval though. I just wonder how much of the additive package has been totally depleted by that long in time? And I think the engine would have to be incredibly tight to keep it from loading the oil with fuel.
 
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quote:
Originally posted by Patman: I guess when I say I find that interval a bit extreme, it's more of a personal comfort level than anything else. I could be convinced if I saw some oil analysis data on cars that have run the full 35k interval though. I just wonder how much of the additive package has been totally depleted by that long in time? And I think the engine would have to be incredibly tight to keep it from loading the oil with fuel.
With alot of highway driving you will have very little fuel dilution, as well as very few cold starts. You have to remember that person would be doing about 3000 a month. Also I would not advise someone who would be pulling extreme loads or doing alot of stop and go(taxi's or cops) do arbitrarily do the 35,000. I would say though it they did, the oil would hold up!!
 
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Falls Church VA
AMSOIL has recommended extended drain intervals (starting at 25,000 miles) for 30 years now. These recommendations are based upon thousands of oil analyses. I've been running extended drains for 25 years now. Most, if not all, the European manufacturers are recommending extended drains. Good idea to keep in mind that the European oil specs are considerably more restrictive than the US specs. In the more powerful Mercedes engines, problems with the extended drain resulted in Mercedes authorizing (maybe requiring?)the use of synthetics. Shop owner last week told us that while some of the oils seem to be holding up OK in the newer Mercedes with the oil monitoring system, he has seen a number of OEM oil filters which turned to mush!! Redline tech stated in an interview that their oil would last as long as any other on the market, and then recommended draining at 15,000 miles.
 

Patman

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Dick, what kind of miles have you been putting on your oil, and do you have any oil analysis results? That is one thing I haven't seen yet, is any oil analysis results on the super long 25-35k intervals.
 
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quote:
Originally posted by Patman: Dick, what kind of miles have you been putting on your oil, and do you have any oil analysis results? That is one thing I haven't seen yet, is any oil analysis results on the super long 25-35k intervals.
All I can say is check out this link, I don't think there are analysis, but the pics are worth a thousand words! http://www.1gr8oil.com/enginedamage.html
 
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Chattanooga, TN
My experience with Amsoil is that around the 12,000 mile mark the oil becomes contaminated with dirt and the lab flags it as time to change. Now, some will say I have a filter issue etc. no, this happens on about every car I have tried it on. Dirt is an absolute element in an analysis unlike copper or iron which can be very high but if you have 15,000 miles on the oil be very normal wear as well. Not true for dirt. 32 ppm is about when mine gets flaged. So, I also would love to see an analysis at 25,000 miles or 35,000 in one year. So at about 12,000 miles is my limit on Amsoil which for me is pretty close to a year anyway. On one car I go a year on the filter too, analysis also fine (low miles/year on this one) . My problem with filters is that the drainback valve fails (horizontal mount filter, verticals are fine) at around 6 months which is probably why Amsoil says to change every 6 months or 12,500. The seal simply fails after that much usage.
 
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Patman- Used to run 30-35,000 on the oil and it tested good. Now, except for the Dodge van, which gets 6-7,000 miles a year, all the cars are turbos. In a year, one gets about 10K, the others much less. When I've taken samples, they test fine. Most of the samples I have on hand are from diesels, many with bypass filter systems. These run on up to 200,000 miles without a drain (testing about every 15,000 and changing filters as recommended by the lab). Gas engine samples are seldom taken, at least my my dealers/customers. Unless a car is driven a lot of miles yearly, putting a bypass filter on it is a toss-up. I do have some showing oil still suitable for use after anywhere from 11,000 miles up to 30,000. And then there are those which show anti-freeze, or high nitration, or fuel dilution--and these were normally sent in because some problem was suspected.
 

Patman

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What kind of TBN and oxidation does Amsoil show at the end of those long intervals? And back to the original question, what kind of intervals would a group 3 synthetic (such as Valvoline SynPower) be able to handle? If I can push Maxlife to 6k intervals, I might just stick to using this oil all the time and not think about going back to a full synthetic again. The price of Maxlife is such a bargain for me, and it's the only affordable source of moly in Canada (Maxlife is $3 per liter when on sale, Redline is $17 per quart!) [I dont know]
 
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Patman, do you have an oil change light? As long as you are not going through heavy dust or towing, it should give you a pretty good indication of when to change the oil. For the Impala it is calibrated to a maximum of 7500 miles, and ususually comes on at around 5-6k for me. I just reset it and go on to 8K with the M1. I could probably let it hit twice though with the oil and filters I run. I think Maxlife would be fine to 6k, I'd just run an analysis on the first drain to make sure.
 

Patman

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I don't have an oil change light on this car, however I did have one on my 97 Grand Prix GTP and based on my driving style and patterns, when I hit 5000 miles I usually had about 30% oil life left, according to that monitor. Before I decide if I can do 6k intervals on Maxlife I will definitely be doing analysis first. The plan will be that once I put in the new SL rated Maxlife (which will be later in the summer, after my Auto-rx and Castrol GTX testing is done), I will slowly increase the intervals with each change, doing oil analysis each time to determine if I can go further, or if I went too far.
 
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Here the limiting factor is DIRT - read silicon - Lets me get to 15,000 for people who don't leave what little asphalt we have (5.5% of the road system), but for the rest I keep it down to 4k to 5k whether they are on Group I, Group II, or Synthetic. I don't like dirt over 15ppm, even though a lot of labs will not flag it until 30 or so. I also have double air filters on 2 vehicles (one paper, one oil sprayed wool)and an air turbine to throw out the big stuff before it gets there.
 
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Patman- >>>What kind of TBN and oxidation does Amsoil show at the end of those long intervals? Varies from car to car. From 1995 Neon, using AMSOIL 0W-30, sample taken 4/29/98, 30,483 miles on oil, 165341 on unit. Tested by CTC Analytical Services, Cleveland OH Oxidation 13.5, Nitration 20.0. TBN not tested. No corrective action required. From 1997 Dodge Ram diesel, using AMSOIL Series 3000 5W-30, sample taken 12/07/01, 151,048 on oil, 155,390 on unit. Tested by Oil Analyzers, Superior WI/ Oxidation 27.8, Nitration 17.1, TBN 12.1, soot <1, Note: This unit was using AMSOIL Bypass Filter
 
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Champaign, IL
Don't you extended-drain guys ever use a carbon cleaning gas additive like Techron, Sea Foam, Mopar Combustion Chamber Cleaner, etc? I use this before every oil change, and these treatments recommend a 3000 mile interval. If I were to use the 3000 mile interval (I do in the Turbo MR2 because I only drive it 1500 mi/yr) then you'd have oil full of carbon for a long long time. Wouldn't that be bad? I run a "long" interval of 6000 miles in my other vehicles and always wait until just before the oil change to use Techron. The oil comes out nasty black from all the crap it cleans out, but the inside of the engine is clean as can be afterwards - I can see a nice silver piston top through the spark plug holes. I wouldn't want that oil to stay in the engine for more than a tankful of gas. This is my gut feeling, is there any real experience of what happens to the oil/engine if you don't change the oil after a Techron treatment? FYI I use Mobil 1, Delvac 1300, and some Quaker State or Pennzoil synthetic I got cheap on closeout (but the race cars get nothing but Mobil 1!).
 
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Chattanooga, TN
I use Techron off and on on one car and see nothing like you report. Oil appears fine at change and I use Techron anywhere in the oil change cycle. I also use Amsoil PI concentrate on a few cars at every tankful and again, oil is ambe when drained even at 7,500 miles or 12,000 miles. In order for Techron to change your oil wouldn't the engine have to have a problem for the combustion gases to affect the oil in that manner?
 

MolaKule

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The most mileage I have been able to get out of any vehicle with Amsoil is approx. 12,000 miles. I haven't done a recent oil analysis, but when I did, the analysis stated the oil was fit for continued use. However, I feel an oil (at least in my vehicles) gets laden with dirt (we live on a gravel road) such that I change the oil about 6k miles, about the time it turns dark brown. I also use the Amsoil foam filters and have to clean and reoil them about 10,000 miles. I also change the filters at 3000 miles.
 

Patman

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I've often heard Terry mention that the OEM air filters are better at stopping dirt than the foam ones, so I wonder if you'd see less silicon on your oil analysis with OEM?
 
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