How many people go with Amsoil 25K changes

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Mar 21, 2004
Near the beach in Delaware
I am currently using Amsoil 5W30 synthetic oil and Amsoil SDF filter and going 25K between oil changes and changing the filter in the middle. Has anyone done this and tested their oil? I would be curious to know the results. The only problem I see is one tends to get very laid back about oil changes. Running this in various passenger cars each driven maybe 15-20K miles/year.
Don, list your vehicles and engine type, please.

Amsoil is good stuff, but it cannot go this distance in many engines!!!!

I have run two cars for the one year Amsoil ASL 5w-30 and Amsoil SDF filters oil change interval and for a nine month OCI with Bosch filters changed at 4.5 months. The wear results from the 9 month OCI was much better. When running the one year, both cars had thickening issues up to a 40 weight.

The Series 2000 0w-30 would be better for a one year/long mileage 10K+ OCI.

Amsoil needs some Lube Control and Fuel Power (do a search in additives) to make the one year interval with excellent wear numbers. I realize that sounds like heresy, but to get the results that Amsoil claims, you need to use FP/LC.
I will drain & sample the oil in my '94 Grand Am 3.0L in about 2-3 weeks. It will have approximately 18-19k miles on it. The first half 12-13k was exclusively interstate & the last was mixed. I will post the results here when completed. I'm using AMSOIL 0W30, SDF oil filter, & AMSOIL air filter. I don't really expect the results to be spectacular be any means.
It's 25k or one year, which ever comes first. Based on the testing here, I'd lower that to 15k max. And if you want to have a great running engine at 150k, then I'd drain it at 10k max. However, 25k can be done on a good synthetic and I do beleive Amsoil/Mobil 1 are the two best long drain oils on the market. I don't trust Redline that long.
Maybe I'm out of it, but do you really save that much by going that long between oil changes? I mean, hey, I can understand it if you want to push your intervals to 5K or even the 7.5K mile that modern engines (run as "light duty") can go. But 10K, 15K, 20K sound rediculous considering the thermal breakdown, soot, acidity, silicon, etc. issues you are sure to encounter.

I know that big rigs routinely go 50K to 75K between oil changes, but then again, they typically have 15+ quart capacities and bypass filters.

I just can't see how you can save much doing this. Not to mention the hassles the manufacturer is almost sure to give you if you try to get any warranty service done, even with oil analyses to back you up.

I REALLY can't see it if anyone has a Toyota engine...

Some enlightenment would be appreciated.

I'm tempted to get mine tested when I do my drain after trying it for one full year. Anyone interested in seeing a lab report on it? My change time is the end of April.

This data is about a year old, but I thought I’d share it with the group of fanatics that we are. The vehicle is a 1996 Grand Cherokee 4x4 with a 242 ,4.0 L, inline six-cylinder. At the time of the sample acquisition the vehicle had 101,311 miles on it. The oil had that was analyzed had 24,033 miles on it and was in the Jeep for 11 months and 16 days. The oil was installed on 12/9/2000. The oil filter was changed on 6/1/01 at 10,655 miles. The oil was drained and a sample was taken on 11/24/2001. The only oil added during the test period was during the six month filter change. Added back ½ quart. The oil level never dropped below the full mark on the dipstick during the test period. Here are the specifics:

Oil type: Amsoil 10W-30 ATM, 6 quarts.
Oil filters Amsoil SDF 15, initial filter and six month change filter.
Air Filter: K&N Filtercharger P/N 332248. Installed new on 12/9/2000. Not serviced during test period.

Analysis performed by Oil Analyzers Inc.

Physical Properties:
Glycol: Neg
% Water: % Fuel: 1.2
Viscosity 40 C: NA
Viscosity 100 C: 13.3
% Solids: TR

Oil Degradation:
Soot: NA
% OXD: 33.3
% NOX: 74.3
TBN: 8.2

Spectrographic Analysis, PPM
Fe: 48
Cr: 2
Pb: 23
Cu: 10
Sn: 3
Al: 10
Ni: 2
Ag: 0
Mn: 1
Si: 17
B: 24
Na: 13
Mg: 322
Ca: 3163
Ba: 0
P: 1222
An: 1522
Mo: 7
Ti: 0
V: 0
Cd: 0

Results of test performed indicate:
Nitration elevated
Viscosity is out of indicated grade
Oil at service limit based on miles/months
Change oil and filters, if not done when sampled
resample at next regular interval

Note: About 1/3 of the way into this test, my Jeep developed an exhaust manifold leak. The exhaust manifold was not replaced until after the test. This likely accounted for the elevated nitration since leaking exhaust manifolds result in a rich fuel mixture in SMPI vehicles. Unfortunately, I was not able to conduct a follow-up analyses with the subsequent oil change. Wife had baby, got busy.

[ December 12, 2002, 04:46 PM: Message edited by: darrenc ]

Originally posted by Horatio:
I'm tempted to get mine tested when I do my drain after trying it for one full year. Anyone interested in seeing a lab report on it? My change time is the end of April.


Greg, everyone is curious about the results of leaving Amsoil in for one year. I don't think anyone has left it in and done a UOA for the ASL/ATM versions of Amsoil. I know you are anxious to see the results yourself.
Go ahead and do an UOA on the one year OCI.
darrenc, yours is a rare case. RARELY if EVER does Amsoil make it to 25k miles with what I would call, good results. Thats asking just too much for an oil. Increasing the sump size and all highway miles can get you there, but your risking deposits. Keeping an engine clean is much more important.
While I don't drive the miles I used to when I worked as a Surveyor for the DOT I used to go 25,000 miles and longer using Amsoil 10W-40. This was from about 1977 to the early 90's.

I am sure some will cringe on that but its worked for me. I never once had a vehicle break down and I racked up many miles. I once recall I went almost 40,000 miles only changing the oil filters and topping off the oil. More important things to worry about that when I wanted to change my oil. Amsoil payed off for me.

2004 GMC SLT E. Cab Z71
2002 Firebird Trans Am WS6
1992 Chevrolet Silverado 4X4 SWB Plow Truck
All one a yearly oil and filters changes.
25,000 miles?????
You guys have got to be joking.... right??

It just blows me away that people will spend tens of thousands of dollars on their vehicles, and then come up with all sorts of stupid ideas on how to ruin them.... Just to save a few all mighty dollars.

I refuse to go any further than 5,000 miles, and thats with synthetic and a "high dollar" (Mobil 1) filter.

I work to hard for my toys, and there is no way I would ever, EVER, even think about some crazy marketing scam of 25,000 miles OCI's.

I'm sorry if this offended anyone, but I just had to get my .02 in.

I'm looking to run the 5W30 in my 4.0 Jeep for 1 year. It won't see the miles but should last the year OCI.

And for those comments about not extending OCI's, why not do it with a good oil? Guess I could just pout in some junk SA oil and drive it until the motor stops rotating.
If the oil is healthy why should I dump it?
I've used Amsoil 5-30 for the first 30,000 miles with first oil change at 1,000 miles. My interval oil change range from 6,000 to 8,000 miles. Went with the Amsoil 0-30 yearly with a 12,000 mile change after 30,000 and knew when the oil needed to be felt like it hit the limit. But I still felt confident the oil was still better than the dino oil even at 10,000 miles. If you believe in synthetic oil that even with extended oil interval, it still lubes better than dino..just opinion....I believe in Amsoil it WORKS.
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