I have a (3rd owner) 06 GMC 3500 drw slt with the duramax/allison package 132k Truck was very well taken care of by previous owners. Right now I'm using Rotella 15/40 I changed ALL fluids as soon as I got the truck home.
I am looking into switching over to this type of system, http://www.amsoil.com/shop/by-product/filters-and-by-pass-systems (look down and click on by-pass units) and going full synthetic Go up to 25k with changing filter 1/2 way
Are any of you using the purple oil that is out???? your thoughts on it???
Diana and Jim said
05:04 AM Jan 17, 2015
I am not an expert on this, but I'm putting it out there for discussion: it is my understanding that once an engine is used to a synthetic/conventional oil, it should not be switched. With that being said, when purchasing a used vehicle, how is a person supposed to know what was run in it by previous owners?
I am interested to hear some responses on this.
Jim
The Junkman said
07:02 AM Jan 17, 2015
I've used them all.. at one time or another. Mostly in pickup's , a car or hot rods / classics.. Including the amsoil / Royal purple / slick 50.. etc..
Nothing seem to make any difference.
I did settle on mobile one full synthetic.. As it's weight will stay more consistent in heat and cold. Keeping oil pressure where it should be.
I think most are gimmicks..
Slick 50 does work pretty good, and quieting things down in a noisy engine.. but I think it may cause seal damage in long term use, and start leaks.. Seems Everytime I use it, 1 year later a rear main seal starts leaking..But I was mostly using it in old cars.. so who knows.
Right not I let the mfg do my oil changes.. since it's their warranty.. And stick with their least expensive.
Second Chance said
08:44 AM Jan 17, 2015
When I first got my Duramax, I did extensive research and reading - everywhere from the Durmax and truck forums to the "Bobstheoilguy" web site, talking with GM certified techs, and picking my brother-in-law's brain (he's driven diesel trucks and tractors for 40 years). The oils that kept bubbling to the top (pardon the pun) were the Mobil 1 synthetic and the Shell Rotella. The only answer I could find about switching from a traditional oil to a synthetic was this: in a vehicle that has used a conventional oil for a long time, some gasket materials will swell slightly. If that vehicle is converted to a synthetic oil, some of these gaskets may shrink and cause some oil leaks. There appears to be no affect on the running parts of the engine, though. I have stuck with the Rotella and AC Delco filters (in all of the reading I did, everyone agreed that the quality/brand of the filter was almost as important as the choice of oil).
With that said, I'll relate an experience I had with my wife's Toyota (realizing it's a COMPLETELY different engine from the diesels in our trucks). I let someone talk me into converting it to synthetic at about 45,000 miles. After the change, the engine went from consuming/loosing NO oil between changes to consuming/loosing up to two quarts between changes. I use the term "loosing" because there was never any smoke to indicate it was being burned. On the other hand, there were also no leaks on the garage floor - so I don't know where it was going! Anyway, I started using the Mobil Super non-synthetic oil in the car again and it hasn't consumed a drop between changes. The only explanation I can find Googling and talking with Toyota is that the molecules in the synthetic oils are smaller than in the petroleum-based oils and can "squeeze" through places that the traditional oil molecules can't. This made sense to me considering the looser tolerances that come with ring-cylinder wall wear, etc.
Rob
Rob_Fla said
12:44 PM Jan 17, 2015
I used Shell Rotella in our previous 2007 Chevy 2500HD Duramax and use it in our current 2012 GMC 3500 HD Duramax.
Never had a problem, I use Rotella because my BIL has been in the Wrecker and Towing business for many years and he uses Rotella in all their vehicles, he gets excellent engine reliability and service using it.
Their vehicles get much more abuse than mine does with lots of idle time, stop and starts in the city and such.
TRAILERKING said
02:17 PM Jan 17, 2015
Not the exact same power train...... But I use Shell Rotella in the 8.3 Cummins and in the MD3060 Allison I use Wolf's Head synthetic since the rebuild of the tranny.
Sushidog said
04:56 PM Jan 17, 2015
I use Rotella in my Ford diesel and Mobil 1 100% synthetic in my car (good info for your toad).
I now have 303,000 miles on my 2.4l Chevy Cobalt and it still doesn't burn a drop of oil, even though I towed with it at 170% of the manufacturer's tow rating for over 40,000 miles. I used Mobil 1 since the car was new. BTW, the oil cap on my car says they recommend Mobil 1 synthetic - so that's what I use. I'm not about to second guess the engineers.
Chip
rocketman said
12:45 PM Aug 12, 2017
I've tried most of them,My Cummins runs best with Rotella T5....
Bill and Linda said
02:07 PM Aug 12, 2017
CJSX2fromCT wrote:
I have a (3rd owner) 06 GMC 3500 drw slt with the duramax/allison package 132k Truck was very well taken care of by previous owners. Right now I'm using Rotella 15/40 I changed ALL fluids as soon as I got the truck home.
I am looking into switching over to this type of system, http://www.amsoil.com/shop/by-product/filters-and-by-pass-systems (look down and click on by-pass units) and going full synthetic Go up to 25k with changing filter 1/2 way
Are any of you using the purple oil that is out???? your thoughts on it???
Owned two Duramax trucks which were always used to pull big 5ers pretty much right at their max spec. Put about 100,000 on the first and 90,000 on the second. Neither burned oil nor had one engine problem whatsoever. Oil, per the book, no additives and it was "dealer oil." Nothing special - But I changed oil and filer every 5,000 miles. Never went as long as the truck "computer" said was OK. Might have gone 6,000 once. 5-6K was about the 50% point on the truck's computer.
Current Cummins gets Rotella 15/40 because - well that's what the book says. I change it at about 7,500 because that's about the 50% point on the truck computer. No issues at some 25,000 miles. Naturally the filter is always changed with the oil - without question.
Personally, while I don't think their is anything wrong with synthetic, if the manual doesn't call for it then I see no reason, IMO, to use it.
An old adage from my father, "Son, if everything else fails, read the directions and do what the guy who designed it told you to do." Worked for me for some 50 years. Naturally YMMV
RonC said
07:27 PM Aug 12, 2017
I do as Bill does ... I use the dealer (Ford) and OEM oil and filters. It makes warranty discussions much easier.
Terry and Jo said
10:40 PM Aug 29, 2017
Two year old thread, so if you are just looking at this thread, be sure that none of the information is out of date.
For those reviving threads, try not to revive one that is more than one year old.
I have a (3rd owner) 06 GMC 3500 drw slt with the duramax/allison package 132k Truck was very well taken care of by previous owners. Right now I'm using Rotella 15/40 I changed ALL fluids as soon as I got the truck home.
I am looking into switching over to this type of system, http://www.amsoil.com/shop/by-product/filters-and-by-pass-systems (look down and click on by-pass units) and going full synthetic Go up to 25k with changing filter 1/2 way
Are any of you using the purple oil that is out???? your thoughts on it???
I am interested to hear some responses on this.
Jim
Nothing seem to make any difference.
I did settle on mobile one full synthetic.. As it's weight will stay more consistent in heat and cold. Keeping oil pressure where it should be.
I think most are gimmicks..
Slick 50 does work pretty good, and quieting things down in a noisy engine.. but I think it may cause seal damage in long term use, and start leaks.. Seems Everytime I use it, 1 year later a rear main seal starts leaking..But I was mostly using it in old cars.. so who knows.
Right not I let the mfg do my oil changes.. since it's their warranty.. And stick with their least expensive.
With that said, I'll relate an experience I had with my wife's Toyota (realizing it's a COMPLETELY different engine from the diesels in our trucks). I let someone talk me into converting it to synthetic at about 45,000 miles. After the change, the engine went from consuming/loosing NO oil between changes to consuming/loosing up to two quarts between changes. I use the term "loosing" because there was never any smoke to indicate it was being burned. On the other hand, there were also no leaks on the garage floor - so I don't know where it was going! Anyway, I started using the Mobil Super non-synthetic oil in the car again and it hasn't consumed a drop between changes. The only explanation I can find Googling and talking with Toyota is that the molecules in the synthetic oils are smaller than in the petroleum-based oils and can "squeeze" through places that the traditional oil molecules can't. This made sense to me considering the looser tolerances that come with ring-cylinder wall wear, etc.
Rob
Never had a problem, I use Rotella because my BIL has been in the Wrecker and Towing business for many years and he uses Rotella in all their vehicles, he gets excellent engine reliability and service using it.
Their vehicles get much more abuse than mine does with lots of idle time, stop and starts in the city and such.
Not the exact same power train...... But I use Shell Rotella in the 8.3 Cummins and in the MD3060 Allison I use Wolf's Head synthetic since the rebuild of the tranny.
I now have 303,000 miles on my 2.4l Chevy Cobalt and it still doesn't burn a drop of oil, even though I towed with it at 170% of the manufacturer's tow rating for over 40,000 miles. I used Mobil 1 since the car was new. BTW, the oil cap on my car says they recommend Mobil 1 synthetic - so that's what I use. I'm not about to second guess the engineers.
Chip
I've tried most of them,My Cummins runs best with Rotella T5....
Owned two Duramax trucks which were always used to pull big 5ers pretty much right at their max spec. Put about 100,000 on the first and 90,000 on the second. Neither burned oil nor had one engine problem whatsoever. Oil, per the book, no additives and it was "dealer oil." Nothing special - But I changed oil and filer every 5,000 miles. Never went as long as the truck "computer" said was OK. Might have gone 6,000 once. 5-6K was about the 50% point on the truck's computer.
Current Cummins gets Rotella 15/40 because - well that's what the book says. I change it at about 7,500 because that's about the 50% point on the truck computer. No issues at some 25,000 miles. Naturally the filter is always changed with the oil - without question.
Personally, while I don't think their is anything wrong with synthetic, if the manual doesn't call for it then I see no reason, IMO, to use it.
An old adage from my father, "Son, if everything else fails, read the directions and do what the guy who designed it told you to do." Worked for me for some 50 years. Naturally YMMV
Two year old thread, so if you are just looking at this thread, be sure that none of the information is out of date.
For those reviving threads, try not to revive one that is more than one year old.
Terry