Last week an Amsoil guy chatted me up at a gas station - he saw my '84 300SD TurboDiesel and asked if I used Amsoil. He claims 15,000+ mile oil changes (with filter changes every 5000) for his turbo diesel Dodge pickup.

My goal is not to ignite a round of the Lubricant Religious Wars but is this for real? Even for my turbo diesel 300SD with 235,000 miles on it?

This is my 1st diesel and my 1st turbo, I bought it 10,000 miles ago so I am very noobie. I've been very happy with synthetic oils for my (non-turbo) gasoline cars over the years, changing between 5,000 and 10,000 miles.

My goal is to get this car well beyond the 500.000 KM badge, not to squeeze pennies on routine maintenance.

My one worry with the car: This car is not an oil leaker nor is it a blue-cloud monger - except when I step on it hard. Then, when the turbo charger engages, it looks like I'm skywriting on the highway. It THAT normal?

Anyway, the Amsoil guy recommends the following:

1. 2 gals of Series 3000 5/30 Heavy Duty Diesel Oil $68
2. 2 gals of ATF (automatic transmission fluid)--good for 50,000 to 100,000 miles--$62
3. 2.3 pts Severe Gear 75-90 (differential lubricant) good for the life of the car.
4. Optional unless you want to do it now: Coolant. Vehicle capacity is 13 qts. Mix 2 gallons of our coolant with distilled water (50 to 70% solution) $48.00--good for 7 years or 250,000 miles. The only non-toxic and biodegradable coolant on the market.

Many thanks for what I assume will be a colorful array of responses, complete with intimate reliance on the Saxon side of our English Language.

Not a big fan of extended drain intervals in a Diesel. Gas motors, yes. But not even heard a good answer as to what happens to the Diesel that contaminates the Oil that cannot cook off and gets left in there over time. A gas motor will eliminate this contamination nicely. A Diesel will not. A filter will not separate Diesel from Motor oil

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1983 300D-Turbo - Deep Blue w Palomino MB Tex (total loss in fire 1/5/09 RIP)
1995 E320 W124 Polar White/Grey Mushroom MB Tex
2005 F150 Supercrew - Arizona Beige - Lear topper
1985 Piaggio Vespa T5 - Black and Chrome

www.cphilip.com

These cars are capable for going 500K miles without synthetics.

I wouldn't use any oil beyond MB's service interval without proper oil analysis.

Only a couple of -30 engine oils are MB rated and Amsoil isn't one of them, last time the document was posted. Stay with -40. -50 should be fine in SoCal.

You don't need 50% antifeeze in SoCal unless you take your car where coolant can freeze. More water = better cooling and I would think you have more need to keep the engine cool than keep coolant from freezing in SoCal so the key IMHO is to use only as much antifreeze as necessary, probably 30-40%. My intuition says to change every 2 years to keep the system clean and replenish anti-corrosives than go 7 years on the same mix.

Smoke under hard acceleration might not be normal but it's very common. If you don't see clouds of smoke the way you normally drive, don't worry about it.

Sixto
87 300D

The key to long oil change intervals is monitoring the soot content in the oil. MB specifies that once the content gets to 2-3%, it's time to change the oil. Depending on a few variables that are dependent on things such as driving style, oil and fuel used, and filtering capability, you may reach the 2-3% point quickly or slowly.

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

5W30 seems kinda thin.

I never been big on MLM stuff, so As soon as i see Amsoil, I shut off. You can use Mobil 1 or Royal Purple with same results.

I ran Royal Purple 15W40 for 12,000 miles, 3000 mile filter changes. No problems, I sent the oil to Blackstone for analysis.

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91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

Amsoil is just a middleman. They buy their base oil from Mobil so you might as well go with the real deal (Mobil).

15,000miles is waaaaayyyyyy too long. 8-10k miles is pushing it, even with synthetic. These old engines make too much soot to go that long on the same oil.

BS. There is no oil that is good enough to last the lifetime of a vehicle. The diff oil should be changed the same as the transmission, every 30,000miles.

You might say the vehicle will last the lifetime of the oil

Sixto
87 300D

Thats how Mercedes did it. The lifetime of the "Filled for life" transmission oil was the warranty length.
Thats fine if you like changing the transmission every x0,000miles instead of the ATF.

The Amsoil man is crazy.....the 617 makes waaay too much soot to be run that way. I change my oil with synthetic every 4k! On the newer diesels 7-8k is possible.....but never any higher than that.

I change my trans fluid/filter every year....its still going strong at 277k! I use synthetic Valvoline Dexron VI in it.

Rear diff I change every few years (probably 30-35k range) with Mobil 1 gear oil.

I am highly opposed to long intervals on fluids....

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Man the stuff I see on here...
With analysis you can definately get to a long duration with a 60x engine. The 61x I'm not so sure about but I've never had one of those that didn't leak so badly analysis wasn't worth doing.
I'm currently doing 12,000 mile changes on my 190D with Mobil 1 5w40, I need some more analysis kits to extend the interval any farther, I think 15,000 is quite achievable. At 12,000 miles soot load is still <1% on my car. MB says the oil must be changed at 2% soot so I'm good to go.

Oil analysis is good for other things too and tells a lot about the internal condition of the engine, $55 for 3 kits last I bought (youroil.net) is cheap enough.

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Sadly Benz-less

Not by the advice of any amsoil salesman (I don't know any) but by my own prerogative when i got my 300 I filled up my diff with severe gear 75w-90, flushed the tranny with who knows how many quarts of amsoil atf (yes drained the torque converter too), flushed the ps system a few times with amsoil atf, and I was running the 5w40 cj-4 oil until I decided to switch to the series 3000 5w30. I use wix full pleated oil filters and I change my oil every 4 months regardless of mileage. (My car is my daily driver) When I was using the 5w40 I was changing every 6 months but it just seemed like the filter shouldn't be pushed that hard. I also change the trans filter and ps filter every 12 months just for good measure and it only costs a few quarts of amsoil atf to do that.

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1982 300D Silver/Blue 612000kms (Sold 2010) Now at 660000kms, original engine, original tranny.

Newer being 1983? MB spec with dino oil for a 617 was every 7500 miles or once a year, whichever came first.

Newer is 1986+.

OEM intervals are always way too long because they want to minimize shop visits and reduce the customer's yearly maintenance costs.

Saving $50/year on oil is not worth risking the engine's lifespan.

Hot and often.

If you want to protect your Engine better install a Bypass Oil Filter System with a low micron filter.

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84 300D, 82 Volvo 244Gl Diesel

Completely agree with you on this. Amsoil or FS2500 kits are great. Typically the bypass filter system will filter 2 or so microns, so cleaning soot from oil will dramatically increase the longevity of the oil. I'd use real oil and not the synthetics personally...with the bypass system. I know gents that use the bypass systems on military vehicles with great success. Many OTR truckers use the bypass systems. The oil typically looks brand new even after thousands of miles.

See link: http://www.fs2500.com/ as an example

Andy

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'95 E300D 313k miles
http://www.ourfullhouse.com