Slickdeals is community-supported.  We may get paid by brands for deals, including promoted items.
frontpage Posted by BabyBubba • Mar 14, 2025
frontpage Posted by BabyBubba • Mar 14, 2025

1-Gallon Mobil Delvac Extreme Heavy Duty Full Synthetic Diesel Engine Oil (15W-40)

$9.75 after $10 Rebate

$20

Walmart
45 Comments 25,749 Views
Get Deal at Walmart
Good Deal
Save
Share
Deal Details
Note: We summarize the promotion terms as offered by the provider, but be sure to personally verify all information and requirements before submitting; we are not responsible for ineligible submissions.

Walmart has select Mobil Delvac Extreme Heavy Duty Full Synthetic Diesel Engine Oils (15W-40) on sale from $9.77 after a Mobil Delvac Rebate, see below for details. Shipping is free w/ Walmart+ (free 30-day trial) or on orders of $35+, otherwise select free store pickup where available.

Thanks to Community Member BabyBubba for sharing this deal.
  • Note: Maximum total of up to $100 back per household, please check the rebate form for full terms & details. Rebate is paid our as a Visa Prepaid Card. Pricing and availability for purchase may vary by location.
Available Options:Rebate Notes:
  • Only eligible Customers may receive a rebate.
  • Fully complete the online proof of purchase form at promotion.mobil.com/offers/delvacrebate. Upload an image of your receipt(s) from a participating retailer dated during the Promotion Period with Eligible Product(s) circled. All online submissions must be completed by 11:59:59 p.m. CST, May 7, 2025. You must complete a separate online offer form for each receipt with Eligible Products. Illegible images will not be accepted.
  • For online purchases, upload the invoice and final delivery or pick-up receipt for your qualifying purchase from a participating retailer.

Editor's Notes

Written by SaltyOne | Staff
  • Offer valid for a limited time only / while supplies last.
  • Please see the Rebate Page for full terms & conditions.
Please see the original post for additional details & refer to the comments below for discussion.

Original Post

Written by BabyBubba
Community Notes
About the Poster
Deal Details
Community Notes
About the Poster
Note: We summarize the promotion terms as offered by the provider, but be sure to personally verify all information and requirements before submitting; we are not responsible for ineligible submissions.

Walmart has select Mobil Delvac Extreme Heavy Duty Full Synthetic Diesel Engine Oils (15W-40) on sale from $9.77 after a Mobil Delvac Rebate, see below for details. Shipping is free w/ Walmart+ (free 30-day trial) or on orders of $35+, otherwise select free store pickup where available.

Thanks to Community Member BabyBubba for sharing this deal.
  • Note: Maximum total of up to $100 back per household, please check the rebate form for full terms & details. Rebate is paid our as a Visa Prepaid Card. Pricing and availability for purchase may vary by location.
Available Options:Rebate Notes:
  • Only eligible Customers may receive a rebate.
  • Fully complete the online proof of purchase form at promotion.mobil.com/offers/delvacrebate. Upload an image of your receipt(s) from a participating retailer dated during the Promotion Period with Eligible Product(s) circled. All online submissions must be completed by 11:59:59 p.m. CST, May 7, 2025. You must complete a separate online offer form for each receipt with Eligible Products. Illegible images will not be accepted.
  • For online purchases, upload the invoice and final delivery or pick-up receipt for your qualifying purchase from a participating retailer.

Editor's Notes

Written by SaltyOne | Staff
  • Offer valid for a limited time only / while supplies last.
  • Please see the Rebate Page for full terms & conditions.
Please see the original post for additional details & refer to the comments below for discussion.

Original Post

Written by BabyBubba

Community Voting

Deal Score
+39
Good Deal
Get Deal at Walmart

Price Intelligence

Model: Mobil Delvac Extreme Heavy Duty Full Synthetic Diesel Engine Oil 15W-40, 1 gal

Deal History 

Sale Price
Slickdeal
  • $NaN
  • Today

Current Prices

Sort: Lowest to Highest | Last Updated 4/26/2025, 12:10 PM
Sold By Sale Price
Walmart$19.77
Leave a Comment
To participate in the comments, please log in.

Top Comments

Lots of people use it in motorcycles and small engines, but the zinc content doesn't go well with gasoline engine catalytic converters, so gas engine automotive use is usually not recommended. There's a lot of information on the net about this.
The rebate combined will the rollback discounted price is the important part, and i posted the most popular viscosity for reference. Anyone interested can take the 15 seconds to go find the 10W-30 or other viscosity they need after clicking through to Walmart. That takes less time (and is certainly more productive) than commenting that this is not the right viscosity for their application.
This is top of the line diesel engine oil. Don't put too much faith in retailer vehicle application recommendations; they are wrong on a regular basis. Your owner's manual always has viscosity and grade information for oil selection.

45 Comments

Sign up for a Slickdeals account to remove this ad.

Original Poster
Pro
Mar 20, 2025
3,570 Posts
Joined Apr 2021
Mar 20, 2025
BabyBubba
Mar 20, 2025
Original Poster
Pro
3,570 Posts
Quote from intex45 :
wondering if this is "BMW certified" for my X5 diesel. The manual strictly says LL-12 or better.
I don't see any mention of LL12 approval. There's also a rumor that it makes your turn signals stop working and makes you weave in and out of traffic.
Mar 21, 2025
9 Posts
Joined Aug 2009
Mar 21, 2025
davmoha
Mar 21, 2025
9 Posts
I use these high zinc oils in my 1970 Datsun 240z and 1972 Datsun 510. The high zinc is great for breaking in new engines like I just installed in my Z. Neither car has catalytic converters.
Mar 29, 2025
150 Posts
Joined Feb 2023
Mar 29, 2025
Kbia
Mar 29, 2025
150 Posts
Quote from BabyBubba :
This is top of the line diesel engine oil. Don't put too much faith in retailer vehicle application recommendations; they are wrong on a regular basis. Your owner's manual always has viscosity and grade information for oil selection.
Oh master of oil. My new Cub Cadet has the 23 HP Kohler KT-Pro 7000 Series. It says SJ or higher, I believe this oil is "higher." All the "experts" are saying this is the wrong oil to use as its too heavy. TIA!
Original Poster
Pro
Mar 29, 2025
3,570 Posts
Joined Apr 2021
Mar 29, 2025
BabyBubba
Mar 29, 2025
Original Poster
Pro
3,570 Posts
Quote from Kbia :
Oh master of oil. My new Cub Cadet has the 23 HP Kohler KT-Pro 7000 Series. It says SJ or higher, I believe this oil is "higher." All the "experts" are saying this is the wrong oil to use as its too heavy. TIA!
I'm far from the master. But I'll share a few thoughts. Diesel engine oil has been widely adopted in small engine use due to its excellent anti-wear properties. As you know, spec ratings like SJ aren't used in diesel oils; they have their own rating spec which is different. However, as oil technology continues to advance it's a given that premium brand diesel oils will adhere to the same high standards as gasoline engine oils.

I won't advise you what oil to run; that's ultimately your decision. However, given your Kohler spec, I would not hesitate to run a 10W30 through 10W50 full synthetic diesel oil in my Kohler. I would stay away from any 15W prefix viscosities for optimum lubrication at cold start. Lower viscosity oils within your acceptable range (10W30) will give you maximum power and fuel efficiency, whereas higher viscosity oils within that range (10W50) will give you better film strength and wear protection at the expense of fuel efficiency and maximum power. I personally prefer to run the higher viscosity when given the choice, for the sake of engine longevity.

One of the biggest differences in diesel oil is zinc content, which is advantageous to small engine use as a wear preventative. It goes without saying, but since your Cub Cadet is new I would strictly adhere to the manufacturer's warranty specification for oil until the warranty runs out. In this case, that means automotive oil with SJ or higher rating and no diesel oil.

I will add that running full synthetic oil and changing it regularly keeps your engine internals almost spotless, with zero sludge build-up. On my vehicles I change oil and filter every 3,000 miles, on mowers and such I go every 100 hours or once a year, whichever comes first. It's also advisable to install a fuel shut-off valve on your mower, to close when not in use. This prevents a leaky carb needle and seat from pushing gasoline into your crankcase (also a necessity when trailering your mower due to the bouncing action), which has ruined many a good mower engine.
Last edited by BabyBubba March 29, 2025 at 06:09 AM.
Mar 29, 2025
150 Posts
Joined Feb 2023
Mar 29, 2025
Kbia
Mar 29, 2025
150 Posts
Quote from BabyBubba :
I'm far from the master. But I'll share a few thoughts. Diesel engine oil has been widely adopted in small engine use due to its excellent anti-wear properties. As you know, spec ratings like SJ aren't used in diesel oils; they have their own rating spec which is different. However, as oil technology continues to advance it's a given that premium brand diesel oils will adhere to the same high standards as gasoline engine oils.

I won't advise you what oil to run; that's ultimately your decision. However, given your Kohler spec, I would not hesitate to run a 10W30 through 10W50 full synthetic diesel oil in my Kohler. I would stay away from any 15W prefix viscosities for optimum lubrication at cold start. Lower viscosity oils within your acceptable range (10W30) will give you maximum power and fuel efficiency, whereas higher viscosity oils within that range (10W50) will give you better film strength and wear protection at the expense of fuel efficiency and maximum power. I personally prefer to run the higher viscosity when given the choice, for the sake of engine longevity.

One of the biggest differences in diesel oil is zinc content, which is advantageous to small engine use as a wear preventative. It goes without saying, but since your Cub Cadet is new I would strictly adhere to the manufacturer's warranty specification for oil until the warranty runs out. In this case, that means automotive oil with SJ or higher rating and no diesel oil.

I will add that running full synthetic oil and changing it regularly keeps your engine internals almost spotless, with zero sludge build-up. On my vehicles I change oil and filter every 3,000 miles, on mowers and such I go every 100 hours or once a year, whichever comes first. It's also advisable to install a fuel shut-off valve on your mower, to close when not in use. This prevents a leaky carb needle and seat from pushing gasoline into your crankcase (also a necessity when trailering your mower due to the bouncing action), which has ruined many a good mower engine.
Thank you so much, I will return this 15w-40 and look for the 10w-30 full synthetic for autos. I was looking for a quality metal fuel shutoff from amazon, but a few that I found had some questionable reviews.
Last edited by Kbia March 29, 2025 at 10:23 AM.
Mar 29, 2025
2,525 Posts
Joined Dec 2003
Mar 29, 2025
feeth
Mar 29, 2025
2,525 Posts
Quote from Kbia :
Thank you so much, I will return this 15w-40 and look for the 10w-30 full synthetic for autos. I was looking for a quality metal fuel shutoff from amazon, but a few that I found had some questionable reviews.
Decided to go w the kohler synthetic blend 10w-30 until the warranty is expired. $10/quart kinda sucks, but it's only once a year.
Mar 30, 2025
310 Posts
Joined Mar 2014
Mar 30, 2025
SteakNCheese
Mar 30, 2025
310 Posts
Quote from BabyBubba :
Hahahaha! ! I've been (sort of) flirting with getting kicked off the site for some time now (Actually the mods are pretty chill and patient with me and in return I try to keep it between the ditches). But I have this dogged determination to help people save money...call it a character flaw. It's just the right thing to do, especially in these wildly inflationary times. Your comment happened to coincide with a YT video that hit my feed for the first time this morning.https://www.youtube.com/watch?v=LqelpONZvpw
I agree with that clip, stupid is everywhere.

Sign up for a Slickdeals account to remove this ad.

Mar 30, 2025
310 Posts
Joined Mar 2014
Mar 30, 2025
SteakNCheese
Mar 30, 2025
310 Posts
Quote from IdahoRoamingGnome :
My Subaru 3.6R at 90k started burning 1qt/3k miles, so ima stick to the normal 5-30w Kirkland oil.
Maybe try valvoline restore and protect, it might clean your oil rings and stop the burning. It has gotten good reviews.
Mar 30, 2025
530 Posts
Joined Nov 2023
Mar 30, 2025
IdahoRoamingGnome
Mar 30, 2025
530 Posts
Quote from SteakNCheese :
Maybe try valvoline restore and protect, it might clean your oil rings and stop the burning. It has gotten good reviews.
Ehhh, might give that a try, but Subarus's flat engines are known to burn oil, along with basically every other newer engine nowadays.
Original Poster
Pro
Mar 30, 2025
3,570 Posts
Joined Apr 2021
Mar 30, 2025
BabyBubba
Mar 30, 2025
Original Poster
Pro
3,570 Posts
Quote from Kbia :
Thank you so much, I will return this 15w-40 and look for the 10w-30 full synthetic for autos. I was looking for a quality metal fuel shutoff from amazon, but a few that I found had some questionable reviews.
The plastic ones aren't bad, and should last at least a few seasons. 2 for $5 with clamps included. I'd install between the fuel pump and carb if possible, instead of between the tank and fuel pump. Better to introduce a possible flow restriction on the pressurized side where effects will be much less.

https://www.amazon.com/Fuel-off-V...r=8-5&th=1

Mar 30, 2025
310 Posts
Joined Mar 2014
Mar 30, 2025
SteakNCheese
Mar 30, 2025
310 Posts
Quote from IdahoRoamingGnome :
Ehhh, might give that a try, but Subarus's flat engines are known to burn oil, along with basically every other newer engine nowadays.
Yep gotta save a ounce of fuel with low tension piston rings.
Mar 30, 2025
530 Posts
Joined Nov 2023
Mar 30, 2025
IdahoRoamingGnome
Mar 30, 2025
530 Posts
Quote from SteakNCheese :
Yep gotta save a ounce of fuel with low tension piston rings.

Yep, esp Toyota with that 0-8w shit that's like $20/qt.
Apr 11, 2025
1,410 Posts
Joined Mar 2012
Apr 11, 2025
Chevyguy85
Apr 11, 2025
1,410 Posts
$80 virtual prepaid card rebate came in my inbox back on the 3rd. The turn around is getting quicker. Less than 3 weeks once I submitted the right receipt or whatever it took.
Apr 12, 2025
1,640 Posts
Joined Dec 2010
Apr 12, 2025
britdude
Apr 12, 2025
1,640 Posts
Quote from feeth :
Decided to go w the kohler synthetic blend 10w-30 until the warranty is expired. $10/quart kinda sucks, but it's only once a year.
On my 12 year old wally gas push mower I use full syn 5W 30. 5W as it makes it so easy to startup on pull start.
Add some stabil and a few drops of techron. Engine runs smooth and very fast.
Yes the deck is all rusted out, but duck tape and safety glasses are your friend
Last edited by britdude April 12, 2025 at 02:07 PM.

Related Searches

Popular Deals

View All

Trending Deals

View All