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15 w 40 Diesel Oil

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Colando

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Does anyone have any info on whether it's OK to use 15w40 diesel oil in a gasser. I have a drum and would like to use it in my Jeep 4L also. :confused:
 
I have been a mechanic for a fleet of about 150 cars, trucks, tractors, bucket and line trucks for 12 years. We run 15w40 in everything. I used to have some reservations and concerns but after 12 years and only one engine failure it seems to be fine.
 
Oil 15w 40 in gasser

When my 96 cherokee was new the dealer (Keifer at Fernandina)

told me to use 20w 50, I thought that was a little too much so I

put 15w 40 Rotella in it. Immediately it started pouring out of the

rear main seal. Just as soon as I could i drew it out and replaced it with

10w 30 and it never leaked again, sold it with 153k miles on it,

4 cyl. 2. 5L.

However the vendor that changed the oil in the CSX company trucks

used Rotello 15w 40 in the gassers and the engines were the last thing

to go, really the only thing that was not replaced during the life of the

vehicle. (these were chevys)
 
If the manual indicates you can run a 40W (ie. 10w40) or even a 50W (ie. 20w50), then you can run a 15w40 without worrying too much... it doesn't flow as well as a 10w or 5w in cold temps, but in hot weather it would most likely work very well. The main thing is to make sure it is "spark rated" like SM or SL, or it can potentially cause the catalytic converter to fail sooner than normal if that is something you need to be concerned with.

For what its worth, I run a 5w40 diesel oil (Rotella 5w40 and Schaeffers 5w40) in two 4-cyclinder cars I own... they responded very well. Mileage is no different than running a 5w30.
 
I just put some delvac 1 synthetic in my lawn mower does that count? That has to be one of the most severe use categories I know of.
 
bmws love delo 15w40, quiets the solid lift valve train in the older models down more then anything else i have tried
 
Engine oil weight for a particular engine is determined by duty cycle as much as anything. If you were racing the vehicle or going to be running it at high speeds for long periods of time, I'd say 15W40 would be OK, as once the engine is warm, it's going to be thin enough to do what it needs to do. If it's not going to be run hard, I'd steer clear of 15W40 for an engine marked for 10W30. The key is operating oil pressure, which is inversely linked to oil temperature. If your engine oil pressure at operating temps is where it should be, you're okay. Read AE Haas' "dissertation" on this before you do it though. Motor Oil 101
 
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I have used 15-40 in all my machines since 1997 My lawnmower,suzuki,golf cart,and my cummins powered pickup. They all run like new

Bob
 
Engine oil weight for a particular engine is determined by duty cycle as much as anything. If you were racing the vehicle or going to be running it at high speeds for long periods of time, I'd say 15W40 would be OK, as once the engine is warm, it's going to be thin enough to do what it needs to do. If it's not going to be run hard, I'd steer clear of 15W40 for an engine marked for 10W30. The key is operating oil pressure, which is inversely linked to oil temperature. If your engine oil pressure at operating temps is where it should be, you're okay. Read AE Haas' "dissertation" on this before you do it though. Motor Oil 101

Thanks for the link ... that is a VERY informative series of articles; I do wonder if it applies to diesels, with their lower rpms and larger internal clearances (I think that's true??), as well as gassers??
 
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If it's not going to be run hard, I'd steer clear of 15W40 for an engine marked for 10W30.







Couple points...



Most engines are spec'd for a range of weights... and almost every owner's manual indicates anything from 5w30 to 20w50 in a gas engine (all of mine did).



The 5w30 (and lighter weights) and their "recommended use" are often regarded as being more for meeting CAFE numbers (read: higher fuel mileages) than engine protection. This isn't saying a 5w20 or 5w30 won't possibly protect as well, but they aren't spec'd by the manufacturer for longevity, but economy.



I run 5w40 Rotella in my 2009 Forester XT (turbo) with good results... I run 5w40 Schaeffers in my 97 Outback with real good results. Most German/European cars are spec'd for 5w40...
 
I use the Diesel 15-40 oil in my race engine and also add red bottle STP additive along with it since oil companys have weakend the oil package additives because of Federal laws.



If you live in a warm to hot area I would use it. "The Jeep 4. 0l recommends 10w30"



Now most all new gas engine autos are setup for 5-20 nowdays, in this case I would just add the ZDDP additive for extra protection.
 
Ams/Oil 15-40



99 Tahoe 350 bought with 150,000 change oil and filter once a year has 202,000 now and still runs great and the oil is dark but you can see through it at the end of a year.



Dr mower, pressure washer, troy built tiller and lawn mower have held up great. I buy the oil by the 55 gal drum, its about $4. 00 a quart.
 
Couple points...



Most engines are spec'd for a range of weights... and almost every owner's manual indicates anything from 5w30 to 20w50 in a gas engine (all of mine did).



The 5w30 (and lighter weights) and their "recommended use" are often regarded as being more for meeting CAFE numbers (read: higher fuel mileages) than engine protection. This isn't saying a 5w20 or 5w30 won't possibly protect as well, but they aren't spec'd by the manufacturer for longevity, but economy.



I run 5w40 Rotella in my 2009 Forester XT (turbo) with good results... I run 5w40 Schaeffers in my 97 Outback with real good results. Most German/European cars are spec'd for 5w40...



My new 09 Challenger R/T w/5. 7L Hemi, 6 speed manual (therefore no MDS) specs nothing but 5W20. I ran 0W20 Mobil 1 this winter, and the guys at Wallyworld were warning me I could have problems (a few used to work for local Mopar dealers). Appparently, there's a grain of truth, as far as the MDS goes, but some have said that there's a TSB out for overseas vehicles to allow 5W30, even though the 5W20 was spec'd for the MDS (valve system runs off oil pressure. ) and CAFE requirements.



I told him it was a 20 weight oil (syns are based on the viscosity of the oil at op temp, versus "dino" oil, which is based on the viscosity at 100 deg F and they add modifiers for cold start) so it should be fine, besides the package says it meets the DC spec and actually exceeds. Never got a MIL to light up. Went to 5W20 on the 12K oil change since it's summer.



I wouldn't be afraid to run 0/5W30 in it, since there's no MDS, and the pre-MDS hemis ran 5W30 from what I understand.



As for the link I put in regarding oil viscosity and grade, sure, that's from a guy whose experience is in high performance racing engines, etc, but at some basic level it applies to any ICE engine.
 
My new 09 Challenger R/T w/5. 7L Hemi, 6 speed manual (therefore no MDS) specs nothing but 5W20. I ran 0W20 Mobil 1 this winter, and the guys at Wallyworld were warning me I could have problems (a few used to work for local Mopar dealers). Appparently, there's a grain of truth, as far as the MDS goes, but some have said that there's a TSB out for overseas vehicles to allow 5W30, even though the 5W20 was spec'd for the MDS (valve system runs off oil pressure. ) and CAFE requirements.



I told him it was a 20 weight oil (syns are based on the viscosity of the oil at op temp, versus "dino" oil, which is based on the viscosity at 100 deg F and they add modifiers for cold start) so it should be fine, besides the package says it meets the DC spec and actually exceeds. Never got a MIL to light up. Went to 5W20 on the 12K oil change since it's summer.



I wouldn't be afraid to run 0/5W30 in it, since there's no MDS, and the pre-MDS hemis ran 5W30 from what I understand.



As for the link I put in regarding oil viscosity and grade, sure, that's from a guy whose experience is in high performance racing engines, etc, but at some basic level it applies to any ICE engine.







And while I agree with your assessment, and the general premise flow is better; there are a few engines out there that are know to spin bearings with thinner oils... the 2. 5L in my Forester (turbo-charged) is one, which is the same engine used in the WRX. These engines are well know for spun bearings from running thinner oils, and it seems to be alleviated by using a 5w40 (or thicker). The dealer I bought my Forester from strongly suggested 5w40 over the recommended 5w30 weight oil.



In short, if the owner's manual indicates you can use the 40w viscosity, I doubt it will hurt anything.
 
I have always thought about that also. I have a Jeep with the 4. 0 and run Mobil One 0-30 in it. I have thought about using the same Rotella Synthetic 5W-40 that I use in my truck, but I haven't been brave enough since the Jeep does run really well, and it really wouldn't be that much of a cost savings over what it is supposed to get. Scotty
 
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