5wt-40wt syn oil

I am going up where the sun don't shine and it gets down to -30 so I changed over to 5-40wt syn oil as per GM spec in the owner's manual.
First I am the cheapest guy in the world and the oil cost me about $90 at Walmart. I am hoping to leave it in there for a while but worry about next summer -- hopefully no heavy tows.
Second this truck has NEVER run better -- it runs so smooth that I have to check the tack at idle to see if it is running also a noticeable increase in power -- so maybe I will get my money back in fuel savings :D

I have been running Mobil Delvac 5w40 for a couple years now, year round, it gives more protection than the dino stuff. ;) Not a problem with heavy towing, at least what I use. I change oil at 5000 miles, the oil still gets dirty! I don't know why some people claim extended change intervals :rolleyes: Better safe than sorry [img]smile.gif[/img]

George Morrison may have something to say on this topic ;)

I do not know what brand 5W-40 you are running, but with a full synthetic the oil is essentially a straight 40W that is unaffected by both extreme cold and heat. The "W" means a winter rating of 5, not that it is a 5W oil; it is actually a thicker base stock, thicker oil than a typical 15W-40 diesel oil. Thus you get the best of both worlds with a full synthetic engine oil. They generally flow to -40F or lower, provide instananeous oil flow, the same with starting (diesels rely on that oil film for compression; synthetics cling to the walls, provide better sealing on cold starts, much better, quicker starting) yet unequalled protection in heat extremes of summer. This is why many military vehicles that are rapid deployment have Delvac 1 installed at build. They can be deployed to arctic or desert operations with no concern for operability.
You made the right choice, especially if you wanted the best for your $$45,000 vehicle...
George

Buck, regarding extended change intervals with synthetic, here is what I know....George correct me if I am wrong....Synthetic oil is more stable than dyno and essentially the oil base DOES NOT BREAK DOWN. The reason we change our oil is because the additives get used up combating the contaminants. If it wasn't for contaminants the oil could be left in for the lifetime of the vehicle(in theory). Of course you would still need a new filter occasionally. I was in your shoes just recently....I love the synthetic year-round but it is expensive to change the oil every 5k. I did some research and decided to get an Oilguard bypass filter. This filter works with the regular oil filter to super-filter the oil. A typical oil filter may filter down to 15 microns, but the bypass is a 3 micron absolute and a 1 micron nominal. Essentially anything that is a contaminant that can harm the engine or use up the additives is filtered out. The company guarantees you can double the mfg suggested oil change interval. our Duramax is a 10k interval, so 20k on an oil change is guarateed. With oil sampling the company says that 4x the interval is possible. That's 40k on an oil change! I plan to begin with 10k once I install it. I calculated that if I go with the conservative 10k interval the $160 filter system will pay for itself in about 2 yrs with 22k miles a year. It would pay for itself in 1 year with a 20k interval. After that I am saving money!

The kicker is that not only am I saving money and oil, the oil in my engine is as clean as brand new at all times!

Regarding... My oil still gets dirty....George can tell you more, but the color of the oil is a very POOR indicator of its condition. Clean looking oil can be filthy and black oil can be pristine. It all depends on the condition of the additive package and the level of dirt and other contaminating particles and fluids. George and AVlube do an exceptional job of doing oil analysis and follow-up advice. The oil analysis looks like a ticker tape to the average Joe, but George's expert understanding of oil analysis AND the Duramax are unquestionable. Do yourself a favor and get one done. You will learn a LOT!!! SPICER :D

[ 12-12-2003, 04:08 PM: Message edited by: SPICER ]

George, Oil is Mobil Delvac 1 it was the only brand that I could find with the correct ratings on the bottles. I thought it was just my imagination but yes it does start quicker.

Al

Mr. Spicer, I am sitting here smiling as your commments and oil knowledge are excellent. And thank you for your kind comments. It is so enjoyable seeing the very high level of discussion and understanding taking place on this site relating to lubricants and operation.
George

I just ordered a case of Mobil 1 Delvac with oil annalysis kit today ;) . I have 6023 miles on the current oil change. When I get the kit should I get the sample(change oil right away) or rack up some more miles? I think that I should do it ASAP! George/Spicer?

BTW, I am using only a Baldwin 1441 oil filter. Haven't been on any trips less than 20 miles either.

If you have 6000 miles on OEM oil, by all means change it asap.. It is more than ready for the Delvac 1!! Especially with winter upon us..
George

Al, Mobil Delvac 1 is good oil, but not worth it at the $35 a gallon price IMHO. If you want to continue using a 5W40 oil, go down to your local PetroCanada bulk fuel facility and pick up some PetroCanada Duron synthetic 5W40 for around $20 a gallon. This oil has been proven to be just as good as the Mobil 1, but at a much lower cost.

If you can wait till spring, the oil goes on sale, saving another couple of dollars a gallon.

http://www.petrocanada.ca/eng/prodse...eases/9155.htm


Carl

6 2 Carl,

Mobil Delvac is more like $23 a gallon. George at AVLube sell it by the case, 4 gal.

Buck, where are you in S. WI? I'm in Milwaukee. SPICER

You can order Mobil Delvac 1 5W40 right here from George Morrison @ www.avlube.com for $21 per gallon. I don't know about shipping cost. George is an awsome supporter of this site.
I bought mine from a local friend and dealer, otherwise I would not consider buying it from anyone else.

Edit: Sorry 6 2 Carl for misunderstanding. Looks like your $35 is Canadian currency. I was referring to US currency.

As you can see I don't know how to post a quote, can someone help me (step by step please, I am probably part polish. SPICER

Quote:

---

(step by step please, I am probably part polish. SPICER

---

but my wife isn't, SPICER

George, I started using Delvac 5w40 after the first oil change at 3700 miles. I now have 48410 miles on my truck.

How many miles between oil changes using Delvac 1 5w40 with balwin 1441 (OEM replacement) oil filter?

I took some heat :confused: earlier in this post for changing it every 5000 miles :rolleyes:

Spicer, I live between Beloit and brodhead, spend some time in Oconomowoc area as well...

I forgot to add that I have been running the 90hp juice for 20000 miles. How does it effect oil change mileage? More soot...?

George and others,
At what mileage do you think it is optimal to switch from dino to synthetic oil for our Duramax engines? I have read some folks here say these engines continue to "break in" and improve their fuel economy for the first 20,000 miles.
I've got 8K on my 2003 now.
Thanks,
Jim

I can only tell you what I have been told, but I would trust George's opinion more than mine. I was told to keep the original oil in for 3k, then synthetic. This may prolong the break-in, but that is speculation based on oil analysis. If I was doing it over I might have changed it several times in the first 7-10k with conventional, then synthetic.....? SPICER

To reiterate Spicer's excellent thoughts, it is an excellent idea to do several early 'flush' oil changes with a high quality mineral based oil. There is sooo much build dirt, seating wear metals and even casting sand, we must flush, flush flush to get it out. The engine is 'broken in' in the first 50 feet of drive unto the haulage unit.. As in the Corvette, Viper, Porsche, etc. all come with Mobil 1 synthetic oil from the factory. So our major concern is flush vs. break-in.
And a switch can be done to full synthetic whenever convenient.. A couple quick flushes and a change to synthetic in the 3,000 to 5,000 mile area would be excellent.. Then at 10,000 miles 99.9% of the flush would be complete and ready for extended changes with the synthetic if one were desirous to do so, with oil analysis, of course....
George