Oil (weight) Change??

Carl Stouffer

Carl Stouffer

Well-known member
Jan 15, 2009
4,705
391
83
Tucson, Arizona 85718
Background:

When I got the coach about 8-1/2 years ago (66,000 miles), the PO told me he was using some sort of Walmart 20W50 oil. Being a big fan of Castrol GTX
20W50 myself, When I did my first oil change, that it what I used. After reading about the ZDDP concerns, I did some research and switched to
Valvoline VR-1 20W50 and have been using that ever since. The coach now has just under 100,000 miles on it and the oil pressure is good (according to
the suggestion of a stock gauge) and oil consumption seems to be at an acceptable level (on the just completed round trip to Las Vegas, about 900
miles, it used one quart).

The coach now has almost exactly 3,000 miles since the last oil change and I am considering changing to Rotella 15W40. The reasons are; Price of the
oil (VR-1 is about $6.00/ qt) and a concern, also read about on this forum, that the heavier weight oil might be hard on certain internal engine parts
(oil pump) at start up.

I am interested in opinions about whether I should make the change or stick with what has worked for the last 34,000 + miles, and why.

Thanks guys,
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging
 
I did a lot of research into motorcycle oil ( stressed by the shearing action of the shared gearbox gears) and found that DIESEL Rated oils are
superior, however in wet plate motorcycle clutches synthetic was sometimes a problem . For my use in a big air cooled Deutz tractor a 0 or 5 - 30 or
40 synthetic makes a huge difference in cold weather starting. I am not big on brand names but Rotella is popular in the farming community here (and
sold in 5 gal buckets) and I do use it. Synthetic oils where originally developed for the highly stressed WW 2 piston airplane engines that wouldn't
run long enough without them . The current VW (I know they are in the bad books for cheating, but they did give use 1k back so far on our car and are
promising more when the courts approve :p ) diesel oil change recommendation with synthetic is 15,000 kilometers or about 9,000 miles. They only
recommend diesel synthetic oil. Synthetic costs more but it could be worth it considering the longer oil change periods.

"There are many molecular compounds present in crude oil and many of those compounds are still present in the refined product, detracting from the
physical properties of that product. For instance, paraffinnic waxes are present in crude-based oil, but contribute nothing to the lubricative
properties of the oil. Also, the size of the hydrocarbon molecules themselves are non-uniform in crude-based oils. Synthetic oil contains none of
these contaminants and the hydrocarbon molecules are very uniform, giving the synthetic oil base better mechanical properties at extreme high and low
temperature"

Group I and II - these are mineral oils derived from crude oil
Group III - this is a highly refined mineral oil made through a process called hydrocracking. In North America this group is considered a synthetic
oil, for marketing purposes.
Group IV - these are true synthetic oils, known as Polyalphaolefin (PAO).
Group V - these are synthetic stocks other than PAO's and include esters and other compounds.
--
Eric & Ree '74 ex-Sequoia + '75 Eleganza Alexandria, Ontario, Canada
 
I have used Shell Rotella for more years than I want to remember.

I currently use Rotella in my diesel John Deere and my GMC. As far as I can tell the two PO's on my GMC also used Shell Rotella exclusively in my
GMC. So I believe it has seen Rotella all of it's 40 years. I have 130,000 miles on my GMC and I use 1 quart of oil per 6000 miles.

Switching to Rotella is not going to give you 6000 miles on a quart because whatever is now worn giving you higher oil consumption will stay worn. I
have heard of people getting some improvement in oil consumption when switching to Rotella but I have no numbers to prove that.

Shell has changed their marketing and products. They now have 3 different products labeled Rotella. The are numbered 4, 5, and 6.

Number 4 is the original Dino oil and is the prime seller to the trucking, industrial, and farm industry. This is the one I use and highly recommend.
(Weight 15W40)

Number 5 is a semi synthetic oil and comes in a lower weight number than the standard 15W40.

Number 6 is full synthetic

My local Walmart sells all 3 of the above. I can not tell how much they sell of each type.

My local Flying J and Pilot also sells all 3. I talked to Flying J and they told me that 90% to 95% of their sales is the original #4. The guys in
the truck stop garage told me that almost all of their oil changes are based on oil analysis and not miles or hours. Also in almost all of their oil
changes the customer specifies original Rotella #4. They did not give me a percentage number.

My local engine rebuilder specifies Rotella #4 (15W40) and they pre-fill Olds 455's and similar types of engines with Rotella #4 (plus one can of GM
EOS) before they go out the door to their customers.

I am not in favor of synthetic oil except in automatic transmissions.

Synthetic does have marginal benefits for engines run outside of normal parameters. As an example below 0 starting or operation above normal engine
temperatures. I do not do either so I do not use synthetics. I change my oil every 6000 miles or once a year in the late fall before I park the GMC
for the winter.

For all of the above reasons, I recommend Rotella 15W40 #4

I need to state that Dick Paterson recommends Rotella 15W40 #4 for the initial break in and the first oil change on his new engines. (I think he
states it in a number of miles.) After that he recommends Rotella #6 (full synthetic).

So you have a differing opinion from a well respected Olds 455 and 403 engine builder.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I only use the T6 Rotella 5w-40 (blue jug) in HD applications. My reasons:
Price: is at $21/gal full price but often on sale and Shell runs $5 mail in rebates often as well as the My Miles Matter program for points. This
makes it cheaper than dino oils
Weight: 5W for fast flow at startup after long sitting. 40 hot gives enough flow past bearings to pull heat away. Heat is what destroys soft bearing
materials. 5w-40 has less parasitic drag and less dist gear loads than 20w-50. I never go heavier than 40 weight in any gas engines
It's Syn: Listen to a Dick Patterson seminar re syn.
I add no add'l ZDDP as more than about 1500 PPM is detremental to polished metal surfaces (cam lobes) due to phosphoric acid attack. (GM released a
TSB regarding spalling from excessive ZDDP levels)
I never use racing oils as most have very low detergents, very low ph stabilizers qty, and very high in antifoam agents for extended high RPM use,
and very short drain intervals. ALL these above are opposite of motorhome service duty conditions.

--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First
 
> Background:
> When I got the coach about 8-1/2 years ago (66,000 miles), the PO told me he was using some sort of Walmart 20W50 oil. Being a big fan of Castrol
> GTX 20W50 myself, When I did my first oil change, that it what I used. After reading about the ZDDP concerns, I did some research and switched to
> Valvoline VR-1 20W50 and have been using that ever since. The coach now has just under 100,000 miles on it and the oil pressure is good (according
> to the suggestion of a stock gauge) and oil consumption seems to be at an acceptable level (on the just completed round trip to Las Vegas, about 900
> miles, it used one quart).
>
> The coach now has almost exactly 3,000 miles since the last oil change and I am considering changing to Rotella 15W40. The reasons are; Price of
> the oil (VR-1 is about $6.00/ qt) and a concern, also read about on this forum, that the heavier weight oil might be hard on certain internal engine
> parts (oil pump) at start up.
>
> I am interested in opinions about whether I should make the change or stick with what has worked for the last 34,000 + miles, and why.
>
> Thanks guys,
I use 10W30 in everything from the 1970s. That is EXACTLY the viscosity a production passenger car engine from that era needs. 15WXX is thicker than
"ideal", but maybe not enough to amount to anything. Emery says the viscosity enhancers break down and the XX gets lower as the oil ages in use. If I
was worried about that, I would switch to 10W40, not 15WXX. OTOH, it seems like the 15WXX can be acquired that contains more ZDDP, which is a long and
unwinnable argument in itself.

Whatever you do, don't switch from dino oil to synthetic. Too much anecdotal evidence that it causes leaks when the synthetic oil cleans up residue
from the past.

If you ever have a NEW engine in something you want to run for more than a quarter million miles, use synthetic exclusively.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
If you've got lots of time to read, this document explains it all:

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

This was written by a degreed mechanical engineer and he tests for the failure point of various oils using a custom-built test fixture. He keeps the
document up-to-date by adding new oils to the list regularly.

In my GMC I usually use 15W-40 Chevron Delo for the following reasons:

1. It has some Moly in it whereas Rotella and many others don't.
2. In the document above, it rates slightly higher than Rotella.
3. The real reason, the cost -- when it's on sale at Costco it's just under $9.00 a gallon.

If I don't have any Delo in the garage I usually have Shell 10W-30 (that I buy when on sale at Costco) and use that to top-up the GMC.

So far the original 455 still runs fine.

JWID, YMMV, WWFMMCYETE (what works for ME may cause YOUR engine to explode), etc.
--
Bob Heller
1974 X-Canyonlands 26ft
Original 455 exc for timing chain,
Rockwell intake, valve covers. 141k miles.
Winter Springs FL
 
Bob,
An interesting blog to read.

I'm amazed to see that the performance of some oils became degraded when an additive was introduced.

It also amazed me that many dino oils were able to outperform synthetics in the "wear protection ranking".

Although I have only skim-read the blog, the message I'm getting is that not all products measure up to their advertised claims. I'm also wondering if what I'm reading is 100% believable?

My biggest observation is that the author isn't proud enough to post his name where it can be easily found. I could only find "540rat".

The absence of his name makes it difficult to verify his credentials and/or look for any published accomplishments.

I'm curious to hear what others have to say about the blog.

Les Burt
Montreal
'75 Eleganza 26'
The EWIP (Eternal Work In Progress)

>
> If you've got lots of time to read, this document explains it all:
>
> https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/
>
> This was written by a degreed mechanical engineer and he tests for the failure point of various oils using a custom-built test fixture. He keeps the
> document up-to-date by adding new oils to the list regularly.
>
> In my GMC I usually use 15W-40 Chevron Delo for the following reasons:
>
> 1. It has some Moly in it whereas Rotella and many others don't.
> 2. In the document above, it rates slightly higher than Rotella.
> 3. The real reason, the cost -- when it's on sale at Costco it's just under $9.00 a gallon.
>
> If I don't have any Delo in the garage I usually have Shell 10W-30 (that I buy when on sale at Costco) and use that to top-up the GMC.
>
> So far the original 455 still runs fine.
>
> JWID, YMMV, WWFMMCYETE (what works for ME may cause YOUR engine to explode), etc.
> --
> Bob Heller
> 1974 X-Canyonlands 26ft
> Original 455 exc for timing chain,
> Rockwell intake, valve covers. 141k miles.
> Winter Springs FL
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
His report is a data nightmare by combining all the permutations of oils and additives. He should have tested all the pure oils and addressed
additives as a separate topic. One good point he made on viscosity is how foam bubbles ( bad) tend to come out of suspension much quicker in lighter
oils. Makes sense. He also confirms what I mentioned about the damaging effects and increased wear of excessive high ZDDP levels Another good point
was the bypass valve % open time as related to high viscosity oils and cold starts. Hopefully the research Rob M is hoping to do on this will give
some real data pertaining to the Olds
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First
 
If you've got lots of time to read, this document explains it all:



https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/



This was written by a degreed mechanical engineer and he tests for the
failure point of various oils using a custom-built test fixture. He keeps
the

document up-to-date by adding new oils to the list regularly.



In my GMC I usually use 15W-40 Chevron Delo for the following reasons:



1. It has some Moly in it whereas Rotella and many others don't.

2. In the document above, it rates slightly higher than Rotella.

3. The real reason, the cost -- when it's on sale at Costco it's just under
$9.00 a gallon.



If I don't have any Delo in the garage I usually have Shell 10W-30 (that I
buy when on sale at Costco) and use that to top-up the GMC.



So far the original 455 still runs fine.



JWID, YMMV, WWFMMCYETE (what works for ME may cause YOUR engine to explode),
etc.

--

Bob Heller

1974 X-Canyonlands 26ft

Original 455 exc for timing chain,

Rockwell intake, valve covers. 141k miles.

Winter Springs FL





 
I'm still a relative GMC newbie, and I am not an expert on Olds engines or motor oil, so I'll leave my opinions on what oil to use out of this thread.
However, one thing I don't see mentioned that would concern me is the drain-back issues the olds V8 is said to have... I too like Castrol 20w50, and
use it in some of my cars, but from what I've read, the Olds motors have a tendency to pump oil up to the heads, and then not have it drain back to
the pan as quickly as needed in some driving conditions... A heavier oil is only going to exacerbate this compared to a thinner oil. Unless of
course your motor has some of the mods needed to improve oil drainback...

My motor was rebuilt by the previous owner a few years back, and I do not know if he made any oiling drainback mods during the rebuild. He did
install an Amsoil dual filter system at that time, which I am happy with, and he ran synthetics after break-in on the rebuild, and I have continued to
do so. But with what I've heard about the Olds oiling issues, I switched from the 15w40 he was running to a 10w30 synthetic... To me the 10w30 is
not too thick to hurt drainback, not too thin to hurt wear....


--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
 
Wondering about the dual filter setup, how it is plumbed, how often it is even in the flow loop vs how often it is being bypassed by the engine's
bypass. My understanding is that filters remove particles. They don't remove liquid combustion byproducts, fuel, acids etc or replenish the oil's
additive package. My theory is that I want the LEAST amount of filter in the way of oil getting to the engine parts yet still trap particles large
enough to do damage due to size. I'd rather just drain a little more often and recycle the used oil to be sure the additive package is not depleted,
and acids building up, rather than try to stretch intervals by add'l filtering. JWID.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First
 
Engines that are inactive for extended periods of time, like our GMC's, are
at risk for internal corrosion from extended oil change intervals. With
combustion by- products in more concentrated form due to extended oil
changes. The manual gives intervals for engines used in severe service. I
use 3500 miles for my coach. I use Valvoline 20/50 Dino in it. It has over
130,000 miles and has not been open. I think I will keep doing what I am
doing. It burns a qt every 1500 miles or so. It is a 403 in a heavy Royale,
and sometimes towing.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

Wondering about the dual filter setup, how it is plumbed, how often it is
even in the flow loop vs how often it is being bypassed by the engine's
bypass. My understanding is that filters remove particles. They don't
remove liquid combustion byproducts, fuel, acids etc or replenish the
oil's
additive package. My theory is that I want the LEAST amount of filter in
the way of oil getting to the engine parts yet still trap particles large
enough to do damage due to size. I'd rather just drain a little more often
and recycle the used oil to be sure the additive package is not depleted,
and acids building up, rather than try to stretch intervals by add'l
filtering. JWID.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> I'm still a relative GMC newbie, and I am not an expert on Olds engines or motor oil, so I'll leave my opinions on what oil to use out of this
> thread. However, one thing I don't see mentioned that would concern me is the drain-back issues the olds V8 is said to have... I too like Castrol
> 20w50, and use it in some of my cars, but from what I've read, the Olds motors have a tendency to pump oil up to the heads, and then not have it
> drain back to the pan as quickly as needed in some driving conditions... A heavier oil is only going to exacerbate this compared to a thinner oil.
> Unless of course your motor has some of the mods needed to improve oil drainback...
>
> My motor was rebuilt by the previous owner a few years back, and I do not know if he made any oiling drainback mods during the rebuild. He did
> install an Amsoil dual filter system at that time, which I am happy with, and he ran synthetics after break-in on the rebuild, and I have continued
> to do so. But with what I've heard about the Olds oiling issues, I switched from the 15w40 he was running to a 10w30 synthetic... To me the 10w30
> is not too thick to hurt drainback, not too thin to hurt wear....

Mark,

Worrying about engine oil viscosity, particularly as to drain back is an interesting thought. The Olds BB has no specific oil return from the valve
gear case. The intended return is down the push rod path to the lash adjuster gallery. I suggest you do an experiment to ease any fears you may
have.

Get appropriate things for handling hot stuff and at least one glass measuring cup.
Get the subject oils that concern you.
Pour a cup of cold oil out into the measuring cup. Put a funnel in the bottle and pour it back in and time how long it takes the funnel to empty.
Repeat with others that are still cold.
Now, in a pan of hot water, heat the measured cup of oil to 200~211°F (you won't get to 212) and do the same.
Repeat with the other(s) when heated.

If you take a 0WXX oil to start with and the other is a 20WXX, you might have seen a difference cold. When you do the same with the hot oils, you
will have a difficult time measuring or seeing the difference. If you can find a funnel with a tiny outlet, it will make more difference. The
orifice tube of a Saybolt Universal rig is about 1/16 diameter and the 60cc of oil goes through that pretty fast.

For the machines in my shop, I have 100 weight (about 5 SAE) and 500 (about 30SAE). In winter when I have let the shop temperature down to about
40°F to save the heat money, you can tell the difference, but in the summer, it is very difficult to tell any difference. There are not viscosity
controlled oils and they have zero anti-wear additives.

Why do I run Mobil 1 20W50?
Because I use synthetic in all the engines that abuse the lubricating oil. This means the coach and my little air-cooled toys. The 20W50 is
published to have all the ZDDP a nice engine needs to stay healthy.

Matt - the refugee from dyno land.
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
According to chart in that oil blog, it appears that the Valvoline VR-1 I have been using had a better anti wear rating than the Shell Rotella by
quite a bit. It was for a different weight than I use, but I would imagine the heavier viscosity would have the same or similar properties as the
lighter viscosity.

Maybe I better stay with the Valvoline. I am not afraid to spend a little extra money on oil. It is a lot less expensive than engines.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging
 
> Wondering about the dual filter setup, how it is plumbed, how often it is even in the flow loop vs how often it is being bypassed by the engine's
> bypass. My understanding is that filters remove particles. They don't remove liquid combustion byproducts, fuel, acids etc or replenish the oil's
> additive package. My theory is that I want the LEAST amount of filter in the way of oil getting to the engine parts yet still trap particles large
> enough to do damage due to size. I'd rather just drain a little more often and recycle the used oil to be sure the additive package is not depleted,
> and acids building up, rather than try to stretch intervals by add'l filtering. JWID.

Even though my rig has the dual filter setup, I still change my oil and filters at regular intervals... Also, Ford and GM both accept the Amsoil
system on warrantied vehicles... If there was any issue with oil flow with them, I'm pretty sure they would void your warranty if you use it. Also,
if you are concerned with restricted flow, my reading indicates most times this is caused by filter media filling up and not allowing oil to pass.
One of the japanese car manufacturers I believe had an issue where they spec-ed filters that were too small, and they were clogging up before the
change interval causing thousands of warranty claims. The twin amsoil filters are quite large... Diesel filter sized, really. You'd need a ton of
contaminents to jam them up.

Also, there really isn't a size threshold on contaminents in your oil. They will still abrade metal surfaces, just not as fast as larger
contaminents.

As for the need for higher viscosity oil for component protection, that's sort of an outdated concept with newer oil technology, and you could be
doing more harm than good. Only "benefit" thicker oils really have over thin, is supposedly better wear protection. However new lubricant
technologies can protect an engine from wear just as well (or better) in a thinner oil weight. OTOH, thick oil has some definite drawbacks: Heavier
oil is slower to get to the places it needs to, especially at startup, when most engine wear occurs. It also flows more slowly through engines,
causing higher bearing temperatures vs the same oil in a thinner viscosity, as it stays in the bearings longer. Also, when a heavy oil is aerated, it
takes longer for the "bubbles" to drop out of suspension vs a thinner weight. Pumping aerated oil through your bearings and wear surfaces is also not
a good thing.

If you read through the blog on 540Rat someone mentioned above, you will see some of these concepts mentioned there... As for another source, here is
an article on Joe Gibbs Racing oils webpage: (Note: Joe Gibbs Racing Oil makes more than just "Racing Oils"...)

http://www.drivenracingoil.com/news/dro/training-center/articles/dont-fall-for-the-myths/

Scroll down to the "Viscosity vs wear myth" heading in the article...

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
 
After looking at that chart on wear resistance, I was wavering on sticking with the VR-1, as it was reted very high. O'Reilly's made the choice
easier by putting the Valvoline 20W50 VR-1 on sale for $4.99/qu. Still expensive, but a substantial savings over the usual 6.65.

Thanks for all the replies.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging
 
You must log in or register to reply here.
Get your shine on at www.cruzingear.co
Applied GMC

Share this page

Share this page
Top Bottom
Back