Oil

5W30 or even 5W20 is the way automakers are going now. Look in the owner's manual or even on one of the stickers under the hood.

What size engine?

caravan 3.8 and dodge ram 4.7.

Applications . All naturally-aspirated and turbocharged four-stroke diesel engines using high or low-sulfur fuels, and four-stroke gasoline engines

. Mixed fleets of diesel and gasoline engines, and/or old and new equipment, such as newest exhaust gas recirculation (EGR) engines with lower exhaust particulate emission standards

I used 15-40 Kendall and high detergent oil in the v-8s before. it should be ok in the 4.7.

id go with a 10w30 in the 3.8

That oil is Fine. I use 20 - 50 in all my 4 cyl and 6 cyl and 8 cyl cars. As the Engine runs and you put miles on the car the oil Viscosity breaks down from heat , gas in the engine. As you drive say 1000 mile etc your oil changes to say - 16w - 45 and lower and lower as you put on more miles. I would never use 5w - 20 or

5w - 30 as the oil will break down real thin like water - so to speak. This will damage the engine. Brian - Las Vegas

I guess you haven't looked at an owner's manual (or the actual oil fill cap) recently, huh?

Today's newer engines are designed for thin oil.

Nothing's changed significantly with respect to engine design. The reason for manufacturers' recommendations for lower-viscosity oils has more to do with fuel economy. Federal rules mandating greater Corporate-Average Fuel Economy (CAFE) has led all the manufacturers to recommend lighter oils, because it takes less power to pump the lighter oil through the engine. Less power used producing oil pressure means less parasitic load, and less fuel used. You can "get by" with the thin stuff, because their aim is only to get their product to last through the warranty period. There's nothing wrong with using a bit heavier oil, in the interest of making the hardware last somewhat longer. As always, consideration should be given to engine size and the expected operating ambient temperature (to name just a couple of parameters) in choosing the viscosity.

The oil channels in modern engines are much smaller than in "ye olden dayes" and the high viscosity oils just can't get to the upper cylinder areas as quickly as the thin stuff. There's also the matter of startup oil pressure. I have real oil pressure gauges on my vehicles, and they all will peg the gauge at 100 psi on cold startup. Put in that pre-90s "syrup" in one, and the engine seals wouldn't last very long, oil pressure relief valve or not. Longevity? I have three vehicles that run very well, they each maintain at least 35 psi at idle, and use almost zero make-up oil between 5,000 mile changes; this is on 5W30 Mobil One, the only oil they've ever seen. Engine longevity? 232,000+ miles, 109,000+ miles, and 158,000+ miles. Thicker oil, my a**.

The hard heads will learn that thicker is not better in newer engines.

Coasty

Yes, things have indeed changed. I won't waste time repeating what Sharon said, see her post.

That certainly has something to do with it, yes.

I think you're wrong here, and when the sludge eventually clogs up the small oil channels enough to restrict the flow of that heavier oil, be sure to come back and let us know.

And other hard heads will find it IS true that CAFE has dictated the use of lighter oils. Are heavier oils necessarily better? Or worse? NO. It depends on a lot of factors - but I will ALWAYS run a slightly heavier oil than recommended by the manufacturer both in warm weather and when running under high load conditions. "Ideal conditions" do NOT EXIST in my world.So I don't use oil recommended for "ideal conditions".

Use the manufacturer recommended weights as many have said. I personally use Shell Rotella Synthetic 5W-40 in my 5.2L Ram & 3.8L Town & Country. I have excellent oil pressure and consumption is great, too. The Chrysler uses less than 1/2 quart in 5000 miles and the Ram uses 1 quart every 3000 miles. They have 139,000 & 160,000 miles respectively.

Hope that helps, Tom

And 5W40 Synth is NOT the recommended oil in either engine. You are using a "heavier oil", which partly by virtue of being a synth, is not heavier when cold.

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Use Mobil-1 synthetic in the viscosity recommended in your owner's manual. Yes it is more expensive but well worth it.

If you have a diesel engine use Mobil-1 Truck and SUV. It's Diesel-rated.