Camper-454 dually- Oil Questions

[WhiteKnight]

My 1997 Sierra SLE 7.4/454 dually calls for 5W30. I've been using conventional oil and it purrs. I always have the Big-Bigfoot camper on it and it comes in at 12,000lbs when I cross the scale. It has 260k/160 miles. I use 75w90 in front diff and 75w140 in the rear diff. Minimal mileage so I oil change yearly.
Question: Conventional oil seems to be getting harder to find and after reviewing lots of posts I'm now of the opinion that the newer synthetics might not cause any leaks. If I switch to synthetic, which I understand is thinner than conventional, should I move up to 10w30 given that I'm always carrying a heavy load. Also, When I first got the unit I learned that a K3500 HD had the option for the heavier oil (I wasn't sure if my k3500 was a HD). Since I was running with such a heavy load I figured it was the safest to use the heavier diff oil.
Thanks. I look forward to the feedback.

 

[nascarnation]

At Allison we ran Mobil 1 15W50 when we used GM big block gassers for transmission tests. That's about as tough an engine cycle as I'm familiar with. We never had lube related failures, although we blew up a LOT of engines, mostly due to valve train parts breaking leading to dropped valves and related carnage.

 

[ripcord]

You'll be fine with a modern synthetic. In fact you'll look long and hard to find a 5w30 that isn't at least a semi synthetic as it's hard for that grade to meet the latest SP spec without some Group III or better base oils, even if it's not labeled as synthetic.

Synthetic oils are NOT thinner than conventional oils, so don't worry about that. They are more thermally stable than conventional, so require fewer additives to stay in grade when hot. If you have good oil pressure you don't NEED to change grades. A 40 grade may give slightly more wear protection under severe service but the difference isn't going to be huge if the engine is in good condition to begin with

 

[eljefino]

If I switch to synthetic, which I understand is thinner than conventional,

Read a little more... it's only thinner when it's wicked cold and even that is a broad generalization.

But imagine, if you start the RV, you're probably going to drive a while. You don't need the cold start protection of a 5w30 and can enjoy a more stable 10w30. A HDEO (heavy duty aka diesel) 10w30 would do you very nicely.

"They" say the 454 went to roller cam in 96 or 97, I would be concerned that an RV would be technologically delayed by a year or two since the cutaways sent to coachbuilders are conservative. Non-rollers like the zinc of the aformentioned HDEO.

Realistically the rest of the RV will fall apart before the engine does. Incidentally, do you have 47k miles? All RVs have 47k miles, it's just a thing I've noticed, LOL.

 

[71Chevyguy]

I would suggest a 10w30 diesel oil as others have mentioned simply because it is well suited for the heavy duty use. I also don't think it would be a bad idea to use a 5w40 A3/B4 euro oil since that is just basically a 5w30 on the thick side and has lots of additives in it.

 

[bullwinkle]

454s always seemed to like 10W30-I would be hitting the Rotella T, or splurge & get the Rotella T5 10W30.

 

[zrxkawboy]

I'd try a 10W30 or 10W40 HM blend.

 

[KneeGrinder]

When I had a 454 W/Camper, heck camper, trailer or empty, I ran Delo 400 15w40, but that was in SoCal and all 454's burn oil. So for your App, I would go with a Diesel 10w30/ 5w40 for winter, 15w40 summer. Do you burn 1 Qt per 1K miles? I have had 3 454's, all rebuilt by me.

 

[wpod]

15W-40 or 15W-50 if the starting temps fit the w viscosity. 0W or 5W 40 would work as well. [especially with winter starts ]

 

[clinebarger]

At Allison we ran Mobil 1 15W50 when we used GM big block gassers for transmission tests. That's about as tough an engine cycle as I'm familiar with. We never had lube related failures, although we blew up a LOT of engines, mostly due to valve train parts breaking leading to dropped valves and related carnage.

The L18 8.1L?

 

[c502cid]

Big block don't care as long as it's full. Don't overthink it.

 

[facility1]

check out Chevron Delo,XSP 5w-30 ,its SN & SN plus,,i know its not talked about much around here,but it is a good heavy duty 5w-30 and worth a consideration in this application with a good reputation.

 

[kschachn]

Read a little more... it's only thinner when it's wicked cold and even that is a broad generalization.

Very broad. The winter rating is a performance standard that can be achieved in multiple ways. To say that a particular base stock is "thinner" is silly.

We'll see if White ever comes back to the discussion.

 

[mrsilv04]

Shell Rotella T4 10w30 Conventional, all the time.

 

[nascarnation]

The L18 8.1L

The L18 8.1L?

In the later years 8.1s with the 1000 series transmission (that was 20+ years ago time passes fast). Before that 7.4s with AT545s.

 

[PontiacHO]

We used 15w40 in our ambulances with 454 gassers. Otherwise it was gaulded valvetrain components.

 

[Fordiesel69]

15w-40 HDEO in boat applications that used the 454.

 

[Rob_Roy]

My 1997 Sierra SLE 7.4/454 dually calls for 5W30. I've been using conventional oil and it purrs. I always have the Big-Bigfoot camper on it and it comes in at 12,000lbs when I cross the scale. It has 260k/160 miles. I use 75w90 in front diff and 75w140 in the rear diff. Minimal mileage so I oil change yearly.
Question: Conventional oil seems to be getting harder to find and after reviewing lots of posts I'm now of the opinion that the newer synthetics might not cause any leaks. If I switch to synthetic, which I understand is thinner than conventional, should I move up to 10w30 given that I'm always carrying a heavy load. Also, When I first got the unit I learned that a K3500 HD had the option for the heavier oil (I wasn't sure if my k3500 was a HD). Since I was running with such a heavy load I figured it was the safest to use the heavier diff oil.
Thanks. I look forward to the feedback.

I suggest 5w-30 or 10w-30 "High Mileage" oil. The high mileage oils tend to be a bit thicker for a given viscosity grade, and have some seal conditioners that can be helpful for an older rig. I notice reduced oil consumption when I switched my 97 Suburban over to a high mileage 5w-30, and it still has no oil leaks.

Generally you are more likely to have an issue with the transmission than the engine in a GMT400 truck.

 

[WhiteKnight]

Read a little more... it's only thinner when it's wicked cold and even that is a broad generalization.

But imagine, if you start the RV, you're probably going to drive a while. You don't need the cold start protection of a 5w30 and can enjoy a more stable 10w30. A HDEO (heavy duty aka diesel) 10w30 would do you very nicely.

"They" say the 454 went to roller cam in 96 or 97, I would be concerned that an RV would be technologically delayed by a year or two since the cutaways sent to coachbuilders are conservative. Non-rollers like the zinc of the aformentioned HDEO.

Realistically the rest of the RV will fall apart before the engine does. Incidentally, do you have 47k miles? All RVs have 47k miles, it's just a thing I've noticed, LOL.

My vehicle is a 97 GMC PU K3500 454 with a removable camper attached with 260K/160 Miles. Not sure how roller cams fit into the equation?

 

[WhiteKnight]

The L18 8.1L?

L29 7.4 gas