oil change schedule for synthetics

[A. Brown]

I'm changing to amsoil 15w40 at forty thousand. Can I go for 5000 miles between changes? I use fleetguard stratapore no bypass filter thanks.

 

[LSMITH]

Andy, if you are going to go to the expense of synthetics you should look into sampling the oil and running it as long as it is still good. I have heard of changes at 25,000 miles and beyond. Do a search on analysis for some companies that do it.

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99 2500 QC 4X4 AUTO SB 24V LARAMIE SLT 3. 5 LSD 285-75-16'S SPA Boost/EGT Everything but leather NRA Member Great Lakes TDR Member

 

[mbrolin]

Use of synthetic oils does not mean a longer duration between oil changes. The same amount of fuel wash,carbon,etc gets in to the oil regardless.

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2001 HO 6spd,Quad cab,LWB,4x4,Flame Red,all options except for leather,Westin Brushguard/Push bar,Painless wiring,Radio Shack CB,my own design CB mount,Smittybuilt nerf bars,NW Custom rocker covers,Custom built stainless rocker light bars,DeeZee bedrails,Isspro pyro and boost gauges,Jacobs ebrake,Reese 20k 5er hitch(more to come)

 

[Randy J]

Andy, what really matters is how you drive. The owners manual will tell you, you can go up to 7500 miles on a change with the right kind of driving. I'm running Amsoil 15W40 and most of my driving is highway (80% - I have a 35 mile commute to work). I change my filter (Amsoil SDF80) at 5000 miles and add a quart of oil. I then change the oil & filter at 10,000 miles. That would probably be safe if I were running conventional oil. On the other hand, if most of the driving was around town, I would want to change synthetic oil at about 5000 miles, and conventional at about 3000 miles. Good luck.

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Randy Jones, San Antonio, TX, rdj@gvtc.com, 98 1/2 QC, 4X4, American Racing BAJA's, 285/75/16, Amsoil throughout, Superstar 3000 export radio, Firestik antenna with fender mount, Fire-ring cable, Mag-Hytec Deep transmission pan

2000 VW Jetta TDI, auto, 45 mpg average

 

[amsoilman]

Andy,
Amsoil's recommendation for the drain interval using the Heavy Duty Diesel 15W-40 is 2 times longer than normal. It can be extended longer than that if you do oil analysis.

Wayne

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94'SLT 4X4 AT/White in color. Factory Tow Hooks & Running Boards. Amsoil By-Pass filter, Amsoil Air cleaner,and all fluids are Amsoil. Optima "Red Top" batteries.
BD exhaust Brake, BD Torque Lock, BD Torque Converter, Dr. Performance Stage II Injection Pump. Mag-Hytec Diff Cover,Mag-Hytec Transmission Pan, Isspro Pyro, Boost,Oil temp Gauges mounted in 3 Gauge post mount. One gauge monitors Engine Oil, Trans, Diff. Temps.
Wayne Owen

 

[A. Brown]

thanks guys, I too have about a twenty mile commute to work so the engine warms up nicely, right now I'm using rotella and changing out every 3000 with a new filter. I have to admit it's so much fun changing oil on this engine I might be doing it more frequently then I have too.

 

[Vaughn MacKenzie]

Randy. Michael, Andy, I am running Amsoil 15W40 and plan to go 20,000 miles between changes even though most of my driving is stop & go in town. My last sample was after 10,000 miles driving as described in the winter, and contaminants were well below levels recommended for an oil change. I change my Stratapores every 7K (3x per 20,000).

After doing a number of samples on my 2 CTDs it has made me a believer in oil analysis and what a waste it was to change it sooner than 5000 miles!! Diesels are a different ball game than gassers. Ever notice how the oil smells similar to new oil except for a scent of diesel soot, even after 5,000-10,000 miles or more? Try smelling the oil from a gasser after that long. . . ack!!! That is NASTY stuff!! I think diesels emit fewer combustion byproducts that cause oil degradation compared to gassers. An example is the amount of water produced when gasoline is burned, very little or none on a diesel in comparison, so there is less probability of moisture contamination. Soot accumulation and thermal stresses because of the piston cooling and turbo are likely the biggest threat to a diesel's oil.

Vaughn

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'01 2500 QC Shortbed 2wd, 6-speed, 3. 54LSD, Cab & Fog lamps, Camper & Tow Pkg.
BOMBed: DD2 Injectors, PS Boost module, Amsoil air filter, straightpiped exh. , Aeroquip 3/8" fuel line w/tank mounted lift pump, AutoMeter Sport Comp gauges, Line-X'd, Amber turn signal conversion.

 

[TwoSlick]

Andy,

I'd recommend oil analysis and filter changes every 7500 miles in this application. The key things you want to watch are viscosity @ 100C; soot percentage; the depletion in the TBN and oxidation/nitration. If you have any detailed questions about oil analysis, I'd be glad to answer them off-line.

Given your driving conditions, you should easily be able to run 10k between changes with Amsoil (change filters every 5k). I would test it once or twice after 5k just to satisfy yourself it's holding up, but this would be a conservative drain interval, based on my experience.

TwoSlick

[This message has been edited by TwoSlick (edited 04-30-2001). ]