Motor oil weight

leeper wrote:
15W-40 is used in diesel motors.15W-40 Delo and Rotella are for diesel motors as stated on the containers. He was using heavy oil because the motor was getting up in millage and age. Not good for oil pump, makes it work harder. 10W-30 would be a good choice. Use dyno oil.

Hate to get in bicker fest over oil. But Delo and Rotella are rated for gas engines, especially older ones. Here is the current rating on Rotella T4 15W40: API CJ-4, CI-4 PLUS, CI-4, CH-4, CF, SM,
SL, SJ, SH; Caterpillar ECF-2, ECF-3; Ford WSS-M2C171-E

The SH would more than cover an '88, and the only reason it likely does not meet current standards is the extra helping of ant-scuff JD refers to. Which can help with flat tappets.

The 15W40 weight is appropriate for the engine in appropriate temperature range. The oil pump is absolutely not an issue when used in appropriate temperature range. In fact I'd say optimum in many cases. Your recommendation of 10W30 is fine too for an appropriate temperature band. Rotella also has a 10W30 grade which I recommend if you want to use that viscosity..

jerseyjim wrote:

(However..if you have ALL syn or ALL fossil, you have to stick with that should you need to add )

Sorry Jim, that is not true. The only thing you'll do by adding Dino to synthetic oil is slightly negate some of the advantages synthetics provide.

15W-40 is used in diesel motors.15W-40 Delo and Rotella are for diesel motors as stated on the containers. He was using heavy oil because the motor was getting up in millage and age. Not good for oil pump, makes it work harder. 10W-30 would be a good choice. Use dyno oil.

Id use 10W-40 Synthetic

My understanding of Mixed Fleet includes those oils being OK for the old-time flat tappet engines. Some of the newest offerings have a reduced Zinc-something called ZDDP that helps flat tappets but can shorten the life of catalytic converters.

V10's along with most newer V8's, have joined the Roller Tappet crowd and need less zinc. They also have tolerances suited to lighter weight oils.

V10 was a revolutionary change from 460, not an evolutionary one. So I'd suggest not adopting a recommendation for 460 that's based on V10 and other revolutionary engines.

When we had an '83 460, just over 100,000 miles, I used 10W-30 dino oil. The V10 we have now moves much more weight and much bigger frontal area, at about the same MPG the 460 got. But down'n'dirty off-the-line, even hill climbing, GRUNT... 460, Please.

I have never seen a 15W40 Mobil 1 grade. I think a 15W40 such as Delo or Rotella would be just fine. If it were mine and I wanted synthetic, I'd use one of the 5W40 grades of Mobil 1 rated for mixed fleet. I'd be leery of switching it to synthetic if it had not been on synthetic. While it is debatable, I do think there is some slight merit to opinions synthetic causing oil leaks in older high mileage engines which have never seen synthetic. If you're not concerned about that (may not leak or leaks very minor) , synthetic is fine.

PAULDUB: Wow. Where did you get that information? You are describing a BLEND....not synthetic or fossil. ((Just what I said in my post))

A motor of your vintage I would say 10-30 or 10-40 . I run 10-40 on mine. I don't believe 5 weights didn't come around till 90s.
Then Again the previous owner was running 20-50. Maybe he knew that it liked it. He would know the motor.

JKaz

jerseyjim wrote:

(However..if you have ALL syn or ALL fossil, you have to stick with that should you need to add )

You can add either kind of oil to the mix regardless of what you started with. The synthetic blend is just dino oil with an undisclosed amount of synthetic added.

I use Chevron 5-30 in my 1993 Ford 460(58k) E-350 motorhome.Everyone has there favorite oil and opinion but I decided to go with what Les Schwab uses for there oil changes.We have a great mechanic at Schwabs and I value his opinion and smarts and his ability to sniff out any problems forth coming.

He really checks things out when doing the oil/lube and he owns a 460 he has had for ages.