Recently read a post where a guy replied to another that using 10w-30 was a bad choice for our diesels. I just changed my oil and used Castrol 10W-30 (on sale at Kragens 14.99 for 12qts) The supplemental in our Owners manual said that weight is OK if used in warm temps. Any opinions are appreciated.

Thanks
Rich.

I thought it was OK only UNDER 32 degrees. Lemme check.

Have a good one!!

Dan

Sorry, my bad. According to the chart in the diesel supplement, (I looked on mygmlink) it has 15W40 as preferred, but 10W30 can be used as long as the temperature is between 0 and 100 degrees.

Hope this helps.

Dan

I think 10W-30 was only for colder climates. Also check to make sure the oil meets diesel requirements CH or CI. Much of the 10W-30 quart bottled oil for gas engines does not.

I sure as hell wouldnt use it! Thats way to thin IMO in a diesel motor in the summer. Maybe if I lived in alaska or something? The owners manual says 10 30 is ok upto 100 degrees? :eek: I dont have my manual handy, I dont remember it being said it was fine in the owners manual but I have a 03. You also are using a car oil that isnt formulated for use in a diesel. Diesels do have special needs like soot control ect. I would make sure to use a oil that was made for diesels. JMO though. No flames inteneded or anything, I just wouldnt use it :)

I agree, 15/40 or 5/40 Delvac 1 - Diesel oil or nothing. Why use a lesser oil in a 8k engine. If it's to save money, find some place elese to save a buck, but not when it comes to lubrication, it it's availability, check out web sites they will deliver a good grade oil to your doorstop.

Please check to see if that Castrol 10w-30 is CH-4 or CI-4 rated. If it isn't, get it out of there, NOW!

The 05 Diesel supplement book shows a chart that allows the 10W-30 up to 100 degrees F. However the 15W-40 is the preferred oil.
& Deadfurrow is absolutely correct about the CI-4 or CH-4 specification for the oil. The supplement book states that failure to use the recommended oil can result in engine damage not covered by your warranty. So, if the Castrol doesn't comply, get it out of there NOW!

(Since it is your truck, you can run olive oil in the crankcase if you want to, just don't expect it to last very long!)

Britt

The weight of the oil is probably not the biggest factor, but rather the formulation. The heat that a diesel produces and the soot factor will break that oil down quickly. Oil manufacturers add special additives to combat this. If cost is an issue, go buy a diesel fleet oil at Tractor Supply or similar outlet. You can buy it in 5 gal buckets for not much more than than that.

I'm hoping you live near the coast, since N. Cal has been having a heat wave these past weeks, a lot of over 100 deg temps.

So let me get this right: Costco has Delo 400 15w 40 for $37 for 6 gallons (24 qts) including the recycling surcharge (which most ads from our local auto parts stores don't include in their ad price), so you're saving about $3.50, give or take, on 12 qts? If I've got this wrong and you just want to run a lighter weight oil, then I appologise in advance, but:

I'd go with the other's advice and treat your $40k - $50k truck like you can afford a few bucks on the right oil... :rolleyes:

I run 15w 40 all year 'round in Northern Calif..... In all my diesels....

Thanks for all the replies. I'll check on the diesel rating tonight when I get home. I didn't know there was a difference between diesel oil and gasser oil. And yes cost was a concern. Last time I had the oil changed they charged me $63.89 for an oil change. There was a surcharge because it was diesel then another for being a 4x4 then the extra qts it took. OUCH! thought I would cut that in half and do it myself.

BTW I didn't think about shopping costco or tractor supply. I'll do that aswell.

Thanks again
Rich.

The reason for the difference in oil can be sumed up in one word ... SOOT.

You can get Rotella-T 15W-40, Chevron Delo 400 or Mobil for about $7.50 at autozone for a gallon, $22.50 for three. Not much more and real (tm) diesel oil. Pick up a Mobil-1 303 oil filter while your there and your set. Oil is a bit cheaper at Wally World, but the only filters they have come in orange boxes. yuk. Go get the Mobil-1 at Autozone. Others would suggest the ACDelco PF-something-or-the-other. Wix and Baldwin are both good choices. You can also find Rotella-T at Kragen, sometimes they have the other oil, but I have not seen the Mobil-1 filters there, just the wall of orange. I think Costco carries the Chevron stuff, but probably not the filters.

It would be interesting why they charge a surcharge for 4x4. Same engine, same drain plug, same amount of oil. Sounds like a way to make more money for no extra work.

Jim

Well it's confirmed.:mad: Back of the Castrol bottle has nothing regarding CH-4 or 1 so the oil is coming out tomarrow. Anybody know how much the right oil at costco is?

Jim thanks for your input.

Rich.

I run Nothing but Cat 10W30 in my duramax and all of our On and off highway diesel engines. We have over 30 Large diesel on the road and have never had a problem related to the oil itself. It gets up to 100 degrees here at times, and at -30 in the winter It still flows good. At the Cat dealerhip where i work, we only use 10W30 unless requested by the customer, And if its nearing the winter we usually tell them no due to temps and pumpability.

you can get 5w40 Rotella Synthetic at wal mart for 36.00 for 3 gallons. ive got 4500 miles on it and its still light brown. not a bad deal if you go 6000 miles between oil changes.

Bigblockquad,

I was at Walmart the other day and saw the Shell Rotella T 15w-40 and it was less than $7 a gallon. That's what I use. At that price its only slightly more expensive than the Castrol 10w-30 you bought and way better for your engine. Personally I don't think the engine needs the synth and I'm not conviced the extra cost is justified but there are lots of opinions about the right oil on here.

I saw Shell Rotella-T 15-40 gallons at Home Depot for $6.50. Did not buy it because I assumed they would be high for that type of stuff- guess I'll be picking up some oil with my paints and lumber!

I prefer the Delo 400 15w 40, others have there own preference. The best price I have seen it (and it beats all the local sales) is Costco: last I checked it was $37.xx for a 6 gallon case (~$6.25 per gallon), but that price includes our CA oil recycling surcharge, whereas most store prices and ads, I have found, do not.

And get the Mobil 1 M1-303 filter as was suggested above, it's the best. There's a coupon in last sundays paper for PepBoys for up to 2 M1 filters for $9.99 ea., don't know if that's a national ad campaign, but I think Autozone will even match competitors prices...

Good luck with whatever you decide...

If you need to save some bucks, Walmart has a 15-40W diesel rated oil that I've used for 200k miles on one truck with excellent results! I know it's not a fancy oil, but most professionals using diesel engines don't use the special oils and do fine! I have a relative that runs 18 wheelers and uses no additives and bulk 15-40 diesel oils! He gets long life out of his engines without problems! I believe in regular oil changes more that super oils! I know that's a minority opinion on the forum, but most diesel owners just treat their diesel trucks like trucks! When I have repairs it's all the stuff that isn't lubricated by the engine oil!

I am involved with fleets all over the country where I am privy to all the engine oil analysis here is what I find is the best engine oil usage. 15W40 below +32F and straight 30 weight above +32F and you may need a thinner oil in winter months according to your area. Manufacturers today are more concerned with EPA fuel economy test results than good engine protection. I tell everyone do not believe me or the oil salesman, go by engine oil analysis! High polymer oils such as 5W40 can cause ring sizure on diesel engines with small (10 qt) oil capacities. Oil refiners will state on the oil container "certified for diesel engines" but what they forget to say is the oil was tested on a diesel engine with a 60 quart capacity. I find the best oil analysis is with Chevron Dello 400 or Shell Rotella "T".

I am involved with fleets all over the country where I am privy to all the engine oil analysis here is what I find is the best engine oil usage. 15W40 below +32F and straight 30 weight above +32F and you may need a thinner oil in winter months according to your area. Manufacturers today are more concerned with EPA fuel economy test results than good engine protection. I tell everyone do not believe me or the oil salesman, go by engine oil analysis! High polymer oils such as 5W40 can cause ring sizure on diesel engines with small (10 qt) oil capacities. Oil refiners will state on the oil container "certified for diesel engines" but what they forget to say is the oil was tested on a diesel engine with a 60 quart capacity. I find the best oil analysis is with Chevron Dello 400 or Shell Rotella "T".
monty...thanks for your informative posting as well as everyone else. I just bought a new Duramax truck and I think I am going to stay with a conventional 15w40 diesel engine oil. Both Rotella and Delo are easily available to me. Of the two, which one is the better oil? Also, does your fleet experience indicate what lube to use in the differentials? Anyone else please chime in as well.

I don't know which way to go regarding synthetic oil. I may consider going synthetic at around 10k miles but may very well just stay with conventional oil, it's never let me down in the past with 3000 mile changes in my gas engines. There are several opinions regarding synthetic oil on this site. What a wealth of information but it can be a bit overwhelming. Some say waste of money, some say you can go synthetic right away and some say wait for the engine to break in.

Also, money spent on oil is really not an issue. I'm not going to "go cheap" on a truck that listed for over 52k. If synthetic is really the way to go then I'll buy it. If the conventional oil will do just as good a job then I'll buy that.

Thanks

[quote=scottdiesel;

I don't know which way to go regarding synthetic oil. I may consider going synthetic at around 10k miles but may very well just stay with conventional oil, it's never let me down in the past with 3000 mile changes in my gas engines. There are several opinions regarding synthetic oil on this site. What a wealth of information but it can be a bit overwhelming. Some say waste of money, some say you can go synthetic right away and some say wait for the engine to break in.

Also, money spent on oil is really not an issue. I'm not going to "go cheap" on a truck that listed for over 52k. If synthetic is really the way to go then I'll buy it. If the conventional oil will do just as good a job then I'll buy that.

Thanks[/quote]

As for the synthetic question, ask yourself this:
How many fleet operators are using synthetic oil in their fleet vehicles?
I think that you will find that there are darned few fleet operators that will go with the extra expense of synthetic oil. Fleet operators depend on their vehicles for their livelihood. If there was a good cost/benefit ratio for the use of synthetics, then most of them would switch overnight.
I have had gas engines go over 300,000 miles on regular petroleum oils. There are hundreds of OTR trucks that get 500,000 miles plus. When you figure the cost differential for the oil used over the life of the engine, the petroleum based oil looks pretty good on the bottom line.
I'm not saying that there aren't good synthetic oils out there, but the expense of using it over the life of the engine outweighs the benefits realized.
Am I saying that you shouldn't use synthetic oil in your rig? NO, that is your perogative. If you feel comfortable, then go for it.

Britt

Just broke the 1500 mile mark and I went to my Stealer last week for their courtesy oil change. When I went to pick up the vehicle, the invoice stated 5W-30 10 QTS. They did put in the correct filter. I discussed my concern with the Service Writer and later with one of their mechanics. They all said this is what they are using on all vehicles and that my 2500HD DMAX engine was not that large and could handle that oil grade. I further argued that the book says 15W-40 and they told me, their oil was fine and they use it on other DMAX customers. Well I got the hell out of there and the next morning I was at Wal-Mart taking it out. I ordered their standard change with Shell Rotella T 15W-40. The Stealer oil does not have the anti-soot ingredients since it is conventional car oil. Well I paid for my oil change the next morning, not bad for $29 and change. I stayed with the A/C filter. The techician at Wal-Mart emptied out the 5W-30 from it and charged it with the Rotella and screwed it back in. Today I did my rear/front end differentials. Got rid of the factory stuff and poured Mobil 1 75W-90 in both. The rear end was one quart low and the front was half a quart off. I suppose that met their specs right? I also just got back from a camping trip towing my 6000# TT. It was hot on the road, mostly 95 deg. I went up and down the northern Georgia mountains. The fan kept kicking in every once in while but no over heating. Cannot even begin to realize what I would have done to the engine if I kept the 5W-30 in it. I will be going to the Service Manager to complain since this was unacceptable.




2500 HD DMAX GMC Sierra SB SLT 4X4 Stock

Although the viscosity would be a concern, I'd be more interested if the stuff they put in it met the CI-4 - CH-4 designation. If they ignored GM's recommended oil spec, they should be reported to GM.

Ed

Just broke the 1500 mile mark and I went to my Stealer last week for their courtesy oil change. When I went to pick up the vehicle, the invoice stated 5W-30 10 QTS. They did put in the correct filter. I discussed my concern with the Service Writer and later with one of their mechanics. They all said this is what they are using on all vehicles and that my 2500HD DMAX engine was not that large and could handle that oil grade. I further argued that the book says 15W-40 and they told me, their oil was fine and they use it on other DMAX customers. Well I got the hell out of there and the next morning I was at Wal-Mart taking it out. I ordered their standard change with Shell Rotella T 15W-40. The Stealer oil does not have the anti-soot ingredients since it is conventional car oil. Well I paid for my oil change the next morning, not bad for $29 and change. I stayed with the A/C filter. The techician at Wal-Mart emptied out the 5W-30 from it and charged it with the Rotella and screwed it back in. Today I did my rear/front end differentials. Got rid of the factory stuff and poured Mobil 1 75W-90 in both. The rear end was one quart low and the front was half a quart off. I suppose that met their specs right? I also just got back from a camping trip towing my 6000# TT. It was hot on the road, mostly 95 deg. I went up and down the northern Georgia mountains. The fan kept kicking in every once in while but no over heating. Cannot even begin to realize what I would have done to the engine if I kept the 5W-30 in it. I will be going to the Service Manager to complain since this was unacceptable.




2500 HD DMAX GMC Sierra SB SLT 4X4 Stock

Lets get this straight, you had a "courtesy" oil change at the dealer you bought the vehicle from, they not only used the incorrect oil , they allowed the vehicle to leave (TWICE) with a rear differential that was a quart low and a front differential that was a half quart low?
You also say that they are servicing other Dmaxes with the "car" oil?
Someone needs to bring this to the area rep's attention. Apparently this particular dealer doesn't care about his customers. For them to tell you that the Dmax wasn't that large ? What does that have to do with anything? They put the spec in the book for a reason.
I'll bet that they don't have a Dmax rated mechanic either! Censored

I would avoid the service department at all costs at this dealer. :mad:

Britt

You are right about that, they dont. I inquired about that when I was there last. I will be complaining to GM directly after I get a chance to talk with the Service Manager. I always give them a shot up front before I go behind the scene on them, especially since I have the invoice with the information that will discredit their service facility.

I take all my goodies in to the dealer and they charge me $9.97 to put it in, and when I arrived the service guy looks at me in his condescending, and ever threatening stance and says " we can't put synthetics in a Dmax" and " if their is an engine problem we won't cover it" - After making me feel like a Moron in front of all the other people waiting, I went to my truck ( steam coming out of my ears) and pulled the supplement and the label from the oil, and proceeded to take HIM to task, explaining and using show and tell with the GM manual that what I was putting in met OR exceeded GM requirements, and I expected a service person who was working for a GM dealership to know this, and now could I please have another service writer as I feel you are inept, an unqualified to take my service request. BOOYA