First oil change on Duramax. 15w40 or 5w40?

Messages
3
Location
Edmonton, Alberta
Hello, I have a new 07 GMC Duramax which is ready for it's first oil change @ 1000 miles. After spending several hours reading through the archives on this forum, it seems that the prevailing wisdom is to avoid a synthetic for the first couple of oil changes, in favour of a high quality dino such as Delo 400 15w-40. This is clear enough, but what complicates my decision slightly is that I live in a northern climate, and with winter approaching, I would normally switch my vehicles to a lighter weight oil. I know very little about lubricants in general, and virtually nothing about what works best in a diesel. I would appreciate any advice you folks may have. Would the 15w-40 be a good choice in -30c conditions, or should I consider something else?
 
Messages
76
Location
Fairfield, PA
In -30C/-22F(wow, that's cold folks) I would use a 10W/30 conventional or synthetic. At those temps even a 5W/40 or 15W/40's going to be getting rather thick. I would also highly suggest pluging in your block heater at night and maybe even investing in a dedicated coolant heater circulating pump.
 
Messages
1,528
Location
Bohica
If you are in Edmonton, go down to Cheveron Bulk Lubricants in the west end, 118th and 156th or so, (I think). They sell Delo 400 15w40 and the synthetic 5w40. I used Delo 15w40 all last year in Edmonton and had no problems in my Cummins. Cummins wants consumers to wait longer to use syn. I am at 33000 km's and will probably be using syn around December. With your Duramax I would check with the dealer first. But here is the thing that will probably give the best results: Ask around to ALL the Chev dealerships in the city about when to switch, and make your decision based upon what the majority says. I started the truck up last year at -29 plugged in and had almost immediate oil pressure with the Delo 15w40. Great oil. Derek
 
Truckers have been using Delo 15-40 in ALL Climates and it works wonderfully. How about a quality oil pan heater that tapes/glues on? I belive at one time, this site had a sponser in this catogory. I think the company was ? Wolverine?
 
Messages
445
Location
Roanoke, Texas
Forget the oil change. Trade in that duramax before it poops out on ya... Just kidding. I drive a dodge cummins but I hear great things about the duramax. Stay with the 15w 40 oils or maybe the 5w 40 synthetics once you get her broke in. Your not going to go wrong with any of the major brands out there for diesels. They are all good oils. Rotella, delo, delvac or valvoline are all good. I would pick the one that is easiest to come by. I myself run the rotella 15w 40.
 
Messages
785
Location
Western Washington
I would go with a 5w40 for your climate, especially with winter this close. I believe the Chevron 5w40 is a gpIII base oil, so it's not really a "synthetic" oil. I would caution the use of a xW30 oil in that engine, especially being this new. I would go with a 5w40. One thing I always like to do with a relatively new diesel (and you are at the perfect mileage, IMO) is to put a big load on it. Hook 10-15K lb trailer and tow it around for half a day and get the rings seated well. Synthetic oil will not hinder this operation. Then enjoy the truck for the next 300K miles, or until you decide to buy a new truck.
 
Messages
445
Location
Roanoke, Texas
Wreckerman may be right. I didn't see you were in Canada. You may want to run the 5w40. It will give you more protection at startup during the cold part of the year.
 
Messages
2,457
Location
Toronto, Canada
Quote:
In -30C/-22F(wow, that's cold folks) I would use a 10W/30 conventional or synthetic. At those temps even a 5W/40 or 15W/40's going to be getting rather thick
I do not understand the reasoning here. 5W will be thinner at cold startups than 10W. Does it not follow that 5W40 will be better for cold startups than 10W30?
 
Messages
1,528
Location
Bohica
5W40 will be thinner than 10W30 in cold temps, or at least it should be. There is no reason to use 10W30 in cold temps when you have the option of using 5W40 and your warranty calls for a 40 weight oil.
 
Messages
3,435
Location
FL
I would listen to 1040 if I was you or try shell rotella t, which is a groupIII just like wreckerman was talking about. That should not effect your break in in a negative way. JMHO
 
Messages
93
Location
Malaysia
Quote:
I would caution the use of a xW30 oil in that engine, especially being this new. I would go with a 5w40.
May I ask the rationale behind the use of xW40 instead of xW30 in an new engine? I would have thought the reverse is correct. Assuming the engine is not being used in cold weather. Thanks.
 
Messages
785
Location
Western Washington
Although the point is debatable, a 40wt oil is generally the best choice with most 4 stroke diesel engines. A good 5w40 oil will flow plenty well even in some pretty cold climates. More important in cold weather is to not flog the engine until the coolant and oil temperature come up to operating ranges. Shell Rotella T Synthetic is a good gpIII 5w40 that seems to be returning good results. The Esso 0w40 would also be a good choice. I have no personal experience with the Esso, however it is readily available in Canuk2's area so it is certainly worth looking into. Again, I think it is import to reiterate that for more concrete answer as to how an oil is performing is UOA's. Choose the oil that seems like the best fit, run it and see what happens. Tourist, I think that cold weather operation is very important to Canuk2's original post. I do not think that a 30wt is the best choice, however it depends a lot on the way the truck is used. A grocery getter may due fine on a 30wt, however I am assuming the truck will be used as a truck. I also do not like to err on the side of innovation with my 7000+ dollar diesel engine. So, the best compromise would be an 0 or 5w40 since it flows quite well at colder temperatures and is still a 40wt at op temperature. Also, a thinner oil is not advisable at break in as far as I'm concerned. During break in I would either run the oil viscosity that I intend to run the engine on indefinably, or brake it in on thicker oil and then switch to a lower viscosity.
 
Messages
93
Location
Malaysia
Quote:
...brake it in on thicker oil and then switch to a lower viscosity.
Hi. This is the exact part that I don't understand. Care to clarify for me the reason? Thanks.
 
Messages
785
Location
Western Washington
During break-in the precision parts in the engine are "machining" themselves together. The rings will seat to the walls, etc. While this is going on, there is a significant increase in the contact pressures and shear forces at work in the engine. A higher viscosity oil will better be able to handle the higher loads and temperatures that are created. This is of course debatable, and I'm am sure that the thinner than water crowed would disagree with me. I do not think that thicker is always better, however there are certain design parameters that will dictate the needed oil viscosity and in a MD-HD diesel it is typically a light to heavy viscosity 40wt. I hope that helps some.
 
Messages
2,457
Location
Toronto, Canada
Quote:
prevailing wisdom is to avoid a synthetic for the first couple of oil changes, in favour of a high quality dino such as Delo 400 15w-40
This has always puzzled me. Breaking in is the proper mating of parts thru wear. Synthetics lubricate better, so there is less wear but will the parts not mate together properly anyway, it will just take longer. So instead of having an engine broken in at 5k, it will be broken in at 10k, it doesn't seem that bad to me.
 
Messages
1,528
Location
Bohica
Understood what you are trying to explain. There are, however, many synthetic oils that are even thicker at operating temps than dino based 15w40's. Not by much of course, but the specific viscosities can be compared with the data sheets.
 
Messages
785
Location
Western Washington
If brake in is prolonged too long, glazing of the cylinder can occur. The best thing to do it put the truck to work right away. Find something to put a good load on it, a real load not just a bed full of wood. I also recommend that if you use your diesel pickup for a grocery getter that you should repeat this process every once in a while. We just put 3 GMC 5500 Duramax's into service recently and they had syn oil put in at their first change at 1500 miles. They have about 8000 on them now I think and run fine, UOA's look good too. A few people above made reference to auxiliary heaters. I really like some type of aux heater. In a diesel, a coolant heater that in plumbed into the oil cooler in such a way that it heats both the coolant and oil is preferable. International used such a heater on the T444E/7.3L PowerStrokes and it worked very well. A heat pad on the oil pan will also work well. I use the engine heater on my personal diesels even in the middle of summer. The closer you can keep the oil to operating temperature, the less “startup” wear you will have. I have the heater on a timer so it runs for half an hour every other hour which maintains about 100*F coolant temperature and 85-90*F oil temperature without danger of cooking anything.
 
Messages
2,457
Location
Toronto, Canada
Quote:
We just put 3 GMC 5500 Duramax's into service
Off topic, but how do you find the GMC 5500 Duramax? At work we are thinking of buying one. I was wondering how good the Duramax is as compared to the 5.9Cummins or the Mercedes906. We will be getting the Allison.
 
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