I just got done changing the oil in my 2000 Toyota Tacoma and thought I'd ask:  what motor oil do you use?  After removing the factory oil, I've been running synthetic Mobil One 5W-30 and changing it every 3000-4000 miles.

-kill-9

Plain ol' yellow bottle Pennzoil 5w-30.  Every 5000 miles.

Never a failure in any of my cars in 24 years and 000,000s of miles of driving.  

Synthetic oil should last 20,000 plus without needing to be changed.  You're pouring money down the drain for no benefit.  

Valvoline 20w30 in the summer, 5w30 in the winter.

You are doing the right thing, but, hopefully, you broke it in up to 10K with conventional oil.  As for the synthetic being good for 20K, the limiting factor is really the oil filter.  Use the Mobil 1 filter for longer duration, but I still wouldn't go past 5K on the change.  I do this on my car and it is worth the extra money.

I've been using Valvoline for 18 years and have never had a problem.  Currently we have a Ranger, Bonneville, and an F350.

2.3 litre-  5/30 in winter, 10/40 in summer

3.8 litre-  5/30 year 'round

7.5 litre- 10/40 in winter, 20/50 in summer

Change oil/filter every 3~4k miles, clean air filters (K&N) every 10k miles.

That and common sense driving habits have guaranteed mechanical reliability for many miles on all my vehicles.

If you ride a motorcycle, use motorcycle oil.  The polymers used in it will withstand greater sheer pressure as it's designed for engines with constant mesh transmissions.  I haven't worked in shops for almost ten years, but these were the facts back then.

I used that Mobil 1 in my vette only because it would void the warranty. I will admit that when I really ran her hard she got hot. I doubt the Tacoma is a HP engine. That stuff was very expensive and IMO not worth it. Just change the oil every 3000 miles and use the saved money to buy beer.

10W-30 every 3,000 miles.

With all due respect, I strongly disagree.  I have over 7 years experience of changing oil for a living and have seen every type of condition imaginable.  

First off, oil never wears out..period. Weather it be conventional or synthetic, it is the additives that wear out that you have to worry about. The additives are the same in both types of oil. Heat and dirt is what wears out an additive package.

Second: the average car will "burn" about 14,000 cubic feat of air with every gallon of gas burned.  So it really doesn't matter what oil you burn, the amount of dirt entering the engine will be the same.

I have seen synthetic oil changed every 20,000 miles and it is dirty/black as hell.  So what do you really think you are doing to your motor.  Yes, synthetic oil will "surround" dirt particales better than regular.  

The one thing that always surprises me is how people will spend $20K- $40K on a car and then try to save a few dollars on oil changes!!!!

Sgtar15

Castrol 10W-30 in all vehicles during all seasons.  My trucks at 3000 miles, the cars at 5000 miles.  Some say heavier oils during winter, which used to be true, but automotive engines nowadays have much tighter tolerances and smaller oil passages, and heavier oils cannot flow as easily to the places where it is needed most, especially the bearings.  Use what the service manual recommends.  And make sure you use the same brand of oil throughout the life of the engine.  Not all oils are the same and mixing them can be bad news.  And synthetic oils may 'last longer', but the dirt it carries is still the same dirt that regular oils carry, only you're keeping it in your engine longer.

168K on a 95 GMC Jimmy with a 4.3l V6 Mobil One every 3-4K

287K on a 86 Chevrolet K5 Blazer with a 5.0l V8 Mobil One every 3-4K

You do the math!

I also recommend using Mobil One in your Tranny 2x yearly (My Tranny Rebuilder that builds racing trannys is the source of this information)

Texaco Ursa 15W40, Shell Rotella-T 15W40, or Chevron Delo 400 15W40 changed every 2500 miles in my '85 6.2L K10, year-round. The engine's got either 160K or 260K on it, doesn't use excessive oil for a diesel, and still gets over 20mpg combined, so it must not be hurting it too badly!

As far as I know, the reason engine oil has to be changed at certain intervals is because of contaminant buildup in the oil. The contaminant particles that do the most damage to an engine are in the 2-5 micron range, but oil filters generally only filter out 10 micron particles. Thus, additives are needed to agglomerate - clump together - the small particles into clumps large enough to be trapped by the filter media. If you use a full-bypass filter in addition to the factory full-flow filter, you can filter out the 2-5 micron particles which means your detergent additives don't get depleted as quickly. Therefore, 10K or longer oil drain intervals are posible, even with "dinosaur juice." The main reason synthetics are recommended is because they don't suffer from thermal breakdown at high temps like conventional oils do, and they also retain their viscosity at extreme temps. Synthetic 10W30 makes starting an engine in subzero temps [b]much[/b] easier than starting the same engine with conventional 10W30 because the synthetic doesn't become more viscous as the temps drop. It'll flow much easier, which means bearings see more oil sooner upon startup, and your oil filter won't bypass in extreme cold and let unfiltered oil into the engine.

All in all, using a quality S-rated (for spark-ignition engines) or C-rated (for compression-ignition engines) and changing it regularly are the most important things you can do. If the API classification says SJ, or CG-4/CH-4, then it's suitable oil to use in your engine.

Walmart's $10 oil job that uses 10W-30 every 3,000-4,000 miles.  

In a standard carburated car, Valvoline 10-W30 (or sometimes 40 weight for those hot 'Bama summers) every 5000 miles.
In newer sport/performance cars, can't go wrong with Castrol Syntec every 4000 miles (can never trust those rice burners, so it's safe to change earlier).

I believe the most harm done by extended oil changes is the break down of the additives. When the additives break down 10w30 becomes 10w20 then just 10 weight oil.

New oil in the bottle has more and larger pieces of silicon than old black oil that has been run through a undamaged engine oil filter.

I'm with the Valvoline guys!  [beer]

what do you all recommend for a 2002 Cummins with 2500 miles on it?

Karl

10-30 Mobil 1 every 3500 miles.  Buy it buy the case at CostCo for around $24

Pay me now.....or pay me later!........[argue]

                                        Your friendly local cummins distributor has a recommendation for you.....I would use it....[:)]

I have a 95 Tacoma with about 126,000mi on it.  I use Pennzoil 10w40 about every 4000 miles.  Heck, the engine block says change the oil every 7500 miles, or 3500 under extreme conditions (or some numbers like that).  

She's still got it where it counts, and is reliable as heck.  Still gets me at least 20-25mpg in the city.

Any API CH-4 rated oil, either petroleum-based or synthetic, of the proper viscosity rating for your area's expected ambient temperature until the next oil change. I personally prefer 15W40 for year-round use, but CH-4 rated 10W30 seems to be making a lot of headway in winter or extreme cold climates.


Still, the best advice has already been given - check with your local Cummins dealer/service center (not the Dodge dealership, they generally don't know smack about diesels.) The Cummins dealer will have mroe up-to-date info, and can even give you Cummins spec numbers which will be on the oil bottle if it meets Cummins' specifications. Whatever you do, don't skimp on oil, filters, or drain intervals - it's the single most important thing you can do to keep your engine running well for a long time.