using diesel engine oils in gas engines, good or bad?

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1,680
Location
CT
15w40 oils such as Rotella, Chevron delo and mobil delvac I thought were for diesel engines, not gas. I was told that the additives in oils designed for diesel engines can form deposits around the pistons in a gas engine so they shouldn't be used in a gas motor. Is that true? I read so much about people using rotella and delo and delvac in gas engines, isn't that bad or am I missing something? What about using 15w40 (diesel) oils in 4-cyl and V-8 marine gas engines?
 
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700
Location
USA
I am using Delo 400 Sae 30 in my gas v-8 boat. I figure on the bottle, it says mixed fleet gas/deisel. It must be ok. I wouldn't use it if i had a cat. conveter.
 
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6,388
Location
Washington St.
Look on the labels of those diesel lube oil you're talking about. All the ones listed, and many more, are dual rated...they also have the API Service Classification SL for gasoline engines. Many commercial operations with diesel and gasoline engines use one of the oils listed above or something similar. They'll do a good job in your gasoline engine if the viscosity is right for you. Ken
 
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718
Location
Central Texas
1FMF I don't have but 20 thousand miles or so using diesel rated oils. No problem so far with all my gassers using Schaeffer's #700 15w-40. No starting difficulties, no slow system pressure up, no valve tapping or measurable loss of MPG. Many diesel oils also carry spark engine ratings. If you'll do a search you will find some lively discussion on the subject.
 
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308
Location
SF/Bay Area, CA
quote:
Originally posted by JonS: I am using Delo 400 Sae 30 in my gas v-8 boat. I figure on the bottle, it says mixed fleet gas/deisel. It must be ok. I wouldn't use it if i had a cat. conveter.
"Mixed fleet" is the key term. Delo 400 and similar products are primarily marketed to trucking and construction companies. They need an oil for their primary heavy equipment but also need a product for their light trucks. They also don't want to inventory two products for these two types of vehicles so they use a 15W-40 in both. Hence API CI-4/SL or CI-4 for the diesels and SL for the gasoline motors. The light truck OEMs don't necessarily recommend a 15W-40 oil for their engines but it's a wash for the construction or trucking company. And since it meets API SL, it's fine with catalytic converters.
 
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378
Location
West Coast
The “Fleet” oils are generally rated for SJ/SL and CH-4/CI-4 (S=Spark/C=Compression). The additive package in these oils are generally more robust than their SJ/SL only counterparts. They are generally more shear stable, have a higher capacity to buffer acids (higher and more stable TBN), and have a stronger detergent package. In a sense, they have everything a marine oil needs. High and stable TBN to deal with rich running marine engines (gas that is) and a corrosion conducive environment , shear stability for those often and extended high rpm WOT runs, and great deposit control. The Merc oil you mentioned in your other post on the Additive forum is mix of two oils, a 25 weight oil and a 40 weight oil. Very weird. Volvo Penta, who uses the EXACT same marinized GM gas motors as as Merc recommends a straight 30 weigh synthetic oil…go figure. I’ve talked to the Volvo Penta tech people about oil in my 5.0 motor. They thought that 15W-40 or 30 weight “Fleet Oil” was a good fit. George Van Pares (master marine mechanic) from Boatered.com uses Shell Rotella in his shop.
 
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308
Location
SF/Bay Area, CA
quote:
Originally posted by darrenc: The “Fleet” oils are generally rated for SJ/SL and CH-4/CI-4 (S=Spark/C=Compression). The additive package in these oils are generally more robust than their SJ/SL only counterparts. They are generally more shear stable, have a higher capacity to buffer acids (higher and more stable TBN), and have a stronger detergent package.
Spot on!
 
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238
Location
Monterey Park, CA
I have been using Delo 400 15w40 for 5500 miles, and it sure can clean. The bottom of my oil cap used to have brown residue on it, and I could never wipe it clean. I recently wiped it, and all the brown stuff came off. Looks like new now. The detergents in this oil really do a great job. Leo
 
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378
Location
West Coast
Metroplex – The verdict is still out on that Rotella T stuff. You are right about the rating though. I comment pertained to the plain Jane dino oil. Pedaltothemetal -- I’ve experience the same cleansing action in my Jeep 4.0 when I used some Delo 15W-40 after about 50K miles of mixed brand (Penn, GTX, Supreme, Quake, etc.) 10W-30 oil. I mean, the Delo turned black within about 1000 miles from cleaning out the garbage these other oils left behind. After the next change (about 5K miles later), the Delo seemed to look good after 5000 miles.
 
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334
Location
Detroit (Rock City)
This anecdotal evidence is really interesting, and the _idea_ of using an even more robust oil than I do currently is certainly appealing... But, what are the potential downsides? I've read various concerns about 'ash content' and 'deposit formation'; what could Joe (or in this case Robert)-Average-Oilforum-Reader look for to see if there is any harm occuring as a result of the use of a HDD oil? Robert
 
Messages
38
Location
PA, USA
I have been using Rotella T dino 15W-40 in my VW 16V in summertime. This winter I switched to Rotella synth 5W-40 instead of Valvoline 10w-30. Oil pressure went up, engine looks cleaner, no consumption and i did replace my downpipe/CAT this sept. The old CAT was not clogged and perfectly functional. Even the OX sensor was reused.This summer i will switch to Delvac 1300 since i am little pissed with Shell/Wallmart for raising the price on the Rotella synth. If your engine doesn't burn any oil, diesel oils should do just fine.
 
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4,478
Location
Southern California
My understanding of the GF-x ratings are that they refer to a combination of the service (Sx) and the properties that allow the display of "Energy Conserving" in the bottom half of the API "doughnut" on the back of the bottle. coincidentally I've never seen that designation on any multiweight mineral oil that goes higher than 30 weight for its hot viscosity rating. The mixed fleet fluids are no worse in that regard than, say, a gasoline only rated 10W-40 or 20W-50 SL oil - it's not GF-3 rated either. The only currently designated dino GF-3 rated oils I'm aware of (I'm in southern California.) are the SL-rated 5W-20, 5W-30, and 10W-30 weight products.
 
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8,937
Location
SC
quote:
Originally posted by Ray H: My understanding of the GF-x ratings are that they refer to a combination of the service (Sx) and the properties that allow the display of "Energy Conserving" in the bottom half of the API "doughnut" on the back of the bottle. coincidentally I've never seen that designation on any multiweight mineral oil that goes higher than 30 weight for its hot viscosity rating. The mixed fleet fluids are no worse in that regard than, say, a gasoline only rated 10W-40 or 20W-50 SL oil - it's not GF-3 rated either. The only currently designated dino GF-3 rated oils I'm aware of (I'm in southern California.) are the SL-rated 5W-20, 5W-30, and 10W-30 weight products.
Actually, Mobil 1 0w40 is now GF-3 rated. The addtion of this rating makes this oil even more unique. It is the only oil marketed worldwide that meets the highest performance and fuel efficiency standards of EVERY market in which it is sold. And to my knowledge, it is the only Xw40 oil that is GF-3 rated.
 
Messages
263
Location
DFW, TX
quote:
Originally posted by porterdog: But, what are the potential downsides? I've read various concerns about 'ash content' and 'deposit formation'; what could Joe (or in this case Robert)-Average-Oilforum-Reader look for to see if there is any harm occuring as a result of the use of a HDD oil? Robert
I'm bringing this back to the top to see if we can get some opinions on what are the possible problems running a diesel oil in a gasser.
 
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18,449
Location
East of IGO
I used to work for a forklift dealership for 16 years probably 30 ford e350 vans 3 class 8 delivery trucks and 100`s of propane forklifts,they all ran delo 400 and no problems.The vans were run hard and weighed around 8500 lbs loaded. Look at the adds in Amsoil or redline oils
 
Messages
308
Location
SF/Bay Area, CA
quote:
Originally posted by Chris A:
quote:
Originally posted by porterdog: But, what are the potential downsides? I've read various concerns about 'ash content' and 'deposit formation'; what could Joe (or in this case Robert)-Average-Oilforum-Reader look for to see if there is any harm occuring as a result of the use of a HDD oil? Robert
I'm bringing this back to the top to see if we can get some opinions on what are the possible problems running a diesel oil in a gasser.

For your reference, the ACEA specs spell out maximums for sulfated ash. A1 oils must be less than or equal to 1.3% sulfated ash. A2/A3/A4/A5 oils must be less than or equal to 1.5%. All of the heavy duty diesel engine oils being discussed meet this criteria and thus should not cause any deposit formation problems. [ January 22, 2003, 06:02 PM: Message edited by: 68redlines73 ]
 
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