Oil for Motorhome

[ftv37]

This is a 1986 28ft class A with a 454 with 68,000 miles 12,000# gross wt. we pull a lot of hill's here in eastern oregon
Right now it has delo 400le 10w30,should I go 10w40 delo(or other)or Rotella syn and if so what grade

 

[Colt45ws]

Some WalMart's have Rotella T5 SynBlend 10W30. That is what I would use..

 

[JimPghPA]

Gas, or Diesel, and what does the manual say?

 

[umungus1122]

Any good HDEO should serve well. As mentioned the T5 is a good choice at a good price. As to weight, 10w-30 winter and 15w-40 summer, although I suspect you'd be fine with the 15w-40 year round, as long as it doesn't drop much below freezing.

 

[dnewton3]

Your service factor is fairly rugged, but we know nothing of your driving pattern, or your intended OCI.

I suspect the current fill of Delo LE 10w-30 is doing fine. Get a UOA so that you KNOW where you stand, rather than guessing that a thicker oil is "better" (which is not always the case).

I don't know what you pay for the LE in 10w-30; I have never, ever seen it on the shelf anywhere. Are you ordering it and paying full retail? The T5 in 10w-30 is an excellent oil, easily attained at about any W/M, and typically would match the price you're likely paying for the Delo.

Please don't get sucked into the "thicker is always better" mentality. Thicker is probably not going to be worse, but it won't necessarily be "better" either.

Get a UOA. Actually, do a few. See where your current choice stands before you go leaping to another. The LE is an excellent oil.

 

[Jim Allen]

I generally agree with the comments above and I generally vote with the "thinner is better" caucus, but in this could be a situation where a 40 grade is the better choice.

I don't know the exact situation of ftv37's motorhome, but I worked on some back when that one was built and the 454s in most big motorhomes were notorious for cracked heads and manifolds... and short lives because they ran so hot and worked so hard.

The heat was a mostly due to a lack of airflow. I'd be willing to bet that rig runs some bodacious oil temps going down the road. If I were the owner, I'd get an oil temp gauge installed ASAP and if the running-down-the-road temps are >212, my prescription would be a 10W40 or 15W40. If I had to make a WAG on choosing an oil without the oil temp info, I'd choose a 40 grade HDEO to be safe. The typical RV is either running down the highway, straining to go up hills with miles of irate travelers behind ( : < ) or they are parked. The way I see it, a motorhome is not a commute rig, so it isn't often short hopped and that eliminates most of the warmup issues. Let's not even bother to talk about fuel economy.

In '86, that is likely to be a carbureted 454, so by today's standard, especially diesel standards, it's no power house. It likely only knows two throttle positions, full open or closed and going down the road, with the windage of a house and the load of a medium duty truck, it's probably running at a pretty high load factor. That's also conducive to higher oil temps, regardless of cooling system efficiency, or lack thereof

Second point: Being carbureted, and run hard (low rpm, lots of throttle + QuadraJet) it's likely subject to more fuel dilution and that's another potential reason to go up a grade.

Am I now a "rhino" thinner-is-better party member?

 

[bullwinkle]

I used to run my old '73 Class A, Dodge 440 Thermoquad equipped, 11,000 lbs EMPTY motorhome on Castrol GTX 20W50-never had any problems (other than having to stop at every gas station due to the THREE MPG it got & a 30 gallon tank!)-but in these days of lower ZDDP/SM engine oils-stick with a HDEO/diesel rated oil for sure for those flat tappet lifters! If your beast is anything like mine was, it'll run so HOT that anything will work!

 

[addyguy]

I'd run Rotella T6 5W-40 in it. Just a bit more viscosity protection, but still good start-up pump and flow.

 

[m37charlie]

I agree with a lot of the above comments. Incredibly, US mfg'd motorhomes have huge gas sucking petrol engines with tiny 5-6L sumps instead of the IMHO better European solution of a 3L modern diesel (still put out over 300 ft-lb) with a 9-10L sump.
The stress on your oil (in terms of MW-hr/L or kw/L or hp-hr/L) must be incredible.
I'd use a Group III or IV synthetic as suggested, xW40. NOT xw30, because of the heat/load issue. And I'd want an oil cooler and try to find the biggest possible oil pan.
Maybe with a big pan and a cooler you could get your total capacity up to something reasonable like 8-10L.
Figure if you get 7mpg, you use 140 gal in 1000 miles, which is 920 lb. At 0.5-0.6 lb/hp-hr, that's 15-1800 hp-hr or 1100-1500 kwh. With 6000 mi OCI, that is 7-9 MW-hr.
With a 5L sump that is 1.4-1.8 MW-h/L. On oil torture tests like the MB441 and 364 they go to ~5 MW-h/L. By comparison, specific oil stress on car engines are tiny, a few 100 kwh/L.
You certainly don't want to do long OCIs like 15-20K miles unless you drastically increase your capacity.

Charlie

 

[ftv37]

Thanks for all the replies,my driving style is fairly tame mostly 55mph at 1/4 to 1/2 throttle.Temp usually 200 on the flats to 212 on hills.When I got the rig I changed the carb to a edlebrock 750,large tranny cooler oil cooler in the radiator .I think I'll leave it in for now because the temps here are crazy it got down to -4 the other night about mid 20's to mid 30's in the day,and were planning a trip in a few weeks.Then in the spring I'll change to 10-40,again thanks.

 

[440Magnum]

Originally Posted By: ftv37
Thanks for all the replies,my driving style is fairly tame mostly 55mph at 1/4 to 1/2 throttle.Temp usually 200 on the flats to 212 on hills.When I got the rig I changed the carb to a edlebrock 750,large tranny cooler oil cooler in the radiator .I think I'll leave it in for now because the temps here are crazy it got down to -4 the other night about mid 20's to mid 30's in the day,and were planning a trip in a few weeks.Then in the spring I'll change to 10-40,again thanks.


If you're running 10w30 in winter and 10w40 in summer now, I'd say go to Rotella T6 5w40 year round and get the best of both worlds. Love those old big blocks!

 

[440Magnum]

Originally Posted By: m37charlie
I agree with a lot of the above comments. Incredibly, US mfg'd motorhomes have huge gas sucking petrol engines with tiny 5-6L sumps instead of the IMHO better European solution of a 3L modern diesel (still put out over 300 ft-lb) with a 9-10L sump.
The stress on your oil (in terms of MW-hr/L or kw/L or hp-hr/L) must be incredible.

Charlie


Well, if you look at the initial post, we ARE talking about an 80s-vintage motorhome. Most US-manufactured motorhomes these days have a Cummins B-series in them, and yes its better from a power, effiency, and driveability perspective.

But give the old "gas sucking petrol" engines credit- they did the job VERY well back in the day. And big-block engines like the OP's Chevy 454, and the other poster's Dodge 440 are actually very easy on oil, even when worked very hard. Most of the cooling is done by the ample water jackets, and the oil temps aren't astronomical at all. Conversely, you mention a "3L modern diesel," by which I assume you mean something like a Benz CRD in a Sprinter chassis RV. Those are actually kinda notorious for *high* oil temps, aren't they? Certainly higher than a 454 or 440 would ever generate.

People today forget that tandem-axle dump trucks in the 60s and 70s would often have a Dodge industrial 318, Ford industrial 370, IH 345, or a Chevy 350 under the hood, and they'd run for years. Not quickly, but diligently. The bigger ones would get a big-block like a Dodge 413 industrial, or the industrial version of the 454, IH 549, or Ford's industrial 429 among others. Single-axle dumps often had a Chevy 292, Ford 300, GMC 305 v6, or Dodge 225 straight six (industrial versions, of course). No one today would EVER think of putting a small-block sized gasoline v8 or (heaven forbid!) a gasoline six in something that big nowdays, but it used to be the norm.

And speaking of vintage motorhomes, I spotted one on I-10 a couple of weeks back of a type which I hadn't seen in many years- one of the streamlined, tandem rear axle front-drove GMC motorhomes. Humming right along with traffic, not breaking a sweat. IIRC those had an Olds 455 and basically the Toronado front-drive layout. I've always believed (and still do) that the Olds 455 may have been the gasoline v8 best-suited to heavy truck duty of any of the Big 3's engines. Monstrous stroke, more torque than most diesels at low RPM, lots of cooling, HUGE bearings (to the point that they were a liability at high RPM in cars like the 442), and all-around rugged construction. Yet, as far as I know, the only truck-like application it ever saw were those GMC motorhomes. Go figure- but then GMC always did have a tendency to waste some of their best engineering in the wrong applications.

 

[bullwinkle]

The industrial 440 is what that old 440 was (& is-gave it to a buddy of mine who is trying to squeeze it into a Dart)-the 440-3. A great motor, but with gas pushing $3/gallon it would be tough to afford to run it now (it was only $1.50-1.60 back in the day when I ran it, at least 15 years ago). I have seen a couple of those GMC RVs around here, I always wondered what they ran in those!

 

[m37charlie]

I wanted to introduce the concept that the oil in these big gas V8s in RVs is subject to very high specific stress (kw/L or hp/qt or hp-hr/qt or MW-hr/L) compared to either car engines or dedicated truck engines. Mainly due to very small sumps.

Charlie

 

[ftv37]

Any preference as to dino vs syn in this rig,I know this is a can of worms

 

[Steve S]

15w-40 HDEO till freezing. Jim Allen has it dialed in.

 

[roadrunner1]

a 15w-40 is going to be your best option, available everywhere, and competitively priced. i still use two 292 chevy in single axle (c-60) and they have been fed a steady diet of 15w-40 for years. prior to the 15w-40 we run straight 30 in everything

 

[440Magnum]

Originally Posted By: m37charlie
I wanted to introduce the concept that the oil in these big gas V8s in RVs is subject to very high specific stress (kw/L or hp/qt or hp-hr/qt or MW-hr/L) compared to either car engines or dedicated truck engines. Mainly due to very small sumps.

Charlie


But if the oil temperature stays low and consumption doesn't deplete the oil inconveniently fast, then a small sump really doesn't matter, do you think? Oh, sure, it means the oil passes through the bearings more times per hundred miles than a bigger sump, but all that means is you shorten up the OCI a bit. But this is motorhome duty cycle anyway- the calendar is going to dictate oil changes, not the odometer. As easy on oil as big gaasoline v8s were, it really wasn't an issue. Note I use the past tense- those big v8s has sliding cam followers and pretty heavy spring pressures, so they aren't mechanically easy on oil- even when they're idling, so reduced EP additives in modern oils might be an issue for them. But thermally, they're creampuffs on oil compared to a small-displacement turbodiesel.

 

[dnewton3]

Again, we're all making suggestion with NO idea what his OCI is going to be. Dino 10w-30 HDEO could be doing a excellent job, very well, if his OCI is only 5k miles or less. There is no "need" for synthetics if that's all he's going to do.

Further, why not a UOA? Why not KNOW, (rather than guess), the how the current oil holds up? Perhaps the oil does get hot. Perhaps it's oxidizing. Perhaps the insolubes are high. We don't know and neither does he. Further, Jim made a good suggestion to add a gauge (I expected nothing less from a confessed gage-a-holic

).

Most of you are presuming certain conditions exist with no evidence. I'd be the first to admit that 10w-30 and 10w-40 both would likely perform about the same. I prefer the lighter grades; others the thicker stuff.

But KNOWLEDGE IS POWER folks. Why not get a UOA, determine the OCI, and THEN pick an oil? That is proper way to do things; not the other way around.

 

[Jim Allen]

Dave, I agree in terms of the OCI but unless he knows what his oil temps are, how he we choose a viscosity based on a UOA? Maybe over several you could see the signs of oxidation, etc, but in the absence of more data in this case, a 40 grade is the safe choice, for summer anyway.

I'm a big proponent of, "As thin as possible, as thick as necessary." This is one of those thick times I think.

I'm mostly being influenced by what I saw back in the day and all the signs then, oxidized oil on the inside of valve covers, paint burned off engine blocks and other parts, blown head gaskets and cracked heads. If driven carefully, most of these things could be avoided but the way many of those older motorhomes were set up, they had no reserve of cooling capacity at all so a clueless driver could very easily exceed the limit (not talkin' about you ftv37,'cause yout rig's survival and continued use is proof of your mechanical sympathy). The rigs I saw back then were in the latter category. Granted, I was living in a warmish climate at the base of the Sierra at the time, but other experiences and research since then have more or less confirmed those impressions were real life... to my satisfaction at least.