Oil recommendations for GM Vortec 8100

Messages
26
Location
Michigan
I aquired a 2001 GMC Sierra 3500 dually about one year ago with only 57K miles. This truck is used in the non-winter months hauling a 3 horse gooseneck horse trailer around or our old Avion travel trailer - but really nothing more than 7-8K lbs. As soon as I got it I changed the oil, oil filter, tranny fluid & filter and both diffs and intalled new plugs (0.45 gap) and wires and had new manifolds put on both sides. It probably came with 5w30 dino. I first put in Mobil 1 0w30 - it burned about a quart per 1K miles. Next I tried M1 5W30 same thing 1 quart per ~ 1 K miles. About 3-5 K OCIs. Right now it has Delo 10w30 hdeo and consumption is 1 qt per 2 K miles which is not too bad in my mind for a BBC. I have been using AC 454 filters. I have read just about all I can online about these 8.1l 496 Vortecs and this seems to be a common issue. Some have apparently tried a different tstat and that has helped. Anyway, I think now that I have tried a 10w30 hdeo I will try Rotella 5w40 or 0w40 this spring as I have several diesel tractors and a 2003 Dodge 5.9 Cummins 1 ton and see if it improves more with a 40 wt. Some engine builers who specialize in the 8.1 (Raylar) even suggest a 15w40 hdeo and I plan to try that after the 5w40. I think in marine applications people commonly run these 8.1s on 15w40 hdeo and even straight 30 and 40 wt. I am also considering M1 15w50 or one of the 5w50s as well if I can find one. Any thoughts from those with experiences with the mighty 8.1?
 
Messages
7,879
Location
Hudson, NH
Its a known problem with that engine. I think its a combination of new intake manifold gasket, new intake manifold bolts that seal better. Why that makes it consume oil, who knows. But thats the supposed fix for the early 8.1. The bolts cannot be reused as they are part of the problem.
 
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Messages
1,349
Location
Elizabeth. Colorado
Mine runs on whatever, and barely uses any at all between changes @ 4000 miles. I've had big blocks use a qt every 1000 miles but not this 8.1 or my last 8.1 either. Sitting with 5w-40 at the moment, but I tend to run 10w-40 or 15w-40 if I'm pulling a trailer in the summer.
 
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2,005
Location
Jacksonville, FL
A previous employer had a few of these to pick up and deliver tractors for his business, they rarely went anywhere empty and the only time they didn't have a 6000# (empty) equipment trailer on them was when they were in the shop for service. We ran 15w40 Bulk Kubota HDEO year round in the Upper Peninsula of Michigan, the Kubota oil was made by Valvoline. Last I knew all 3 trucks were approaching 300k. They used some oil but not nearly as much as they did on PCMO. I'd just run 15w40 year round if I owned one.
 
Messages
15,056
Location
Canada
Big Chevy's seem to like 40 and 50-weights. Got nothing to 'prove' that, just read that more times than I can count from owners. Good quality 15W-40 would be a good place to start, but 15W-50 or 20W-50 isn't excessive either.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
Yeah seems to be I have one that uses a little oil. There was quite an improvement with 10w30 hdeo so I am hoping 5w40 rotella syn or 15w40 will improve it more. I also am considerin a 10w40 too prolly M1 but I have many gallons of 5w40, 0w40 synth and 15w40 dino in the barn. The spark plugs were nasty and changing them out with new wires made a huge difference. Pulls like a beast now. How often do you change your plugs and wires? I am thinking every 25-30K miles or if it starts to act like a slug.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
Thanks for all the advice guys. My father in law died last year. He had a nice SeaRay and I inherited 6 qts of Mercury marine 25w40, which I understand is about like a straight 32 wt and I toy with the idea of using this next summer but pribably will just use it in the zero turn and other OPE.
 
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10,710
Location
Cincinnati, OH, USA
The 25W40 would be great in summertime hot weather, but not in cold weather (not sure how hot it gets in [censored])-I would use Rotella T5 in it the rest of the year, that oil runs good in everything I put it in.
 
Messages
1,472
Location
Maryland USA
The Mercury Marine 25w40 is nothing special, other than the weight. I have numerous 454 and 8.1 in boats and trucks, so I would recommend a 5w40 for street use, but a 0w40 would be nice to try. You did not mention your location, but if your up north then I would shy away from a 15w40 in the wintertime. At this point, I would not open up the engine if its consuming 1 quart per 1k miles, just live with it until it gets worse. In my boats, I use a full synthetic 20w50 or 15w40 , but they never run in the winter time.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
I am in Michigan so it does get fairly cold now and then - except for this upcoming week it has been quite warm so far. I mostly run 5w40 year run in my deisel equipment and honestly could probably use it year round for every 4 cycle engine I have, but probably like lots of folks on this site I am always on the look out for a good deal on a good oil and with the fantastic Mobil rebates last year I have more than a few gallons of Delvac 1300 15w40 (was $5 per gallon) and also maxed out on Delvac 5w40. I put enough miles/hours on my trucks and diesel equipment that typically change oil 2x a year and if I have found a good deal on some 15w40 that gets used in the warm months and 5w40 in the cold. Still have Delvac 1300 in the ole Dodge though this year just have to remember plug her in! Rubberchicken what full synth 15w40 and 20w50 do you like? I think the only full syn 15w40 i have seen I think was Royal Purple but have seen synth blend 15w40s around.
 
Messages
2,250
Location
Ottumwa, Iowa
I have been around a few of these engines in generators. From what I have read they just use oil no matter what. I put Mobil 1 5w30 in them as the start up and go to 1800 rpm instantly. They came with that short filter but you can use the regular sized Chevy filter if you want. There aren't many options on fancy filters in that short size if that is what you are looking for. Mobil 1 filters are about the only premium filter out there in that size.
 
Messages
1,188
Location
WA
My dad has a 2002 Silverado 2500HD with that engine. He hauls a huge bed camper with his to AZ and back yearly. It has always consumed about 1qt/1k miles on 10W30, except when he used to run AMSOIL in it. Then he would burn 1qt every 6k OCI.
 
Messages
13,194
Location
Maricopa Arizona
Originally Posted by Dudemanmaximus
I am in Michigan so it does get fairly cold now and then - except for this upcoming week it has been quite warm so far. I mostly run 5w40 year run in my deisel equipment and honestly could probably use it year round for every 4 cycle engine I have, but probably like lots of folks on this site I am always on the look out for a good deal on a good oil and with the fantastic Mobil rebates last year I have more than a few gallons of Delvac 1300 15w40 (was $5 per gallon) and also maxed out on Delvac 5w40. I put enough miles/hours on my trucks and diesel equipment that typically change oil 2x a year and if I have found a good deal on some 15w40 that gets used in the warm months and 5w40 in the cold. Still have Delvac 1300 in the ole Dodge though this year just have to remember plug her in! Rubberchicken what full synth 15w40 and 20w50 do you like? I think the only full syn 15w40 i have seen I think was Royal Purple but have seen synth blend 15w40s around.
Use what lube you have for your other equipment keep it simple.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
Concerning the oil filter in a 4x4 I don't think there is any room for any filter much bigger than an AC454 without hitting the front drive shaft. It's pretty tight up there.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
Yeah I agree. If the 8.1 does great on 5w40 or 15w40 that would be great cause I have a lot of that. I just thought it reasonable to start out at the recommended oil weight and move on up from there plus I did score 2 gallons of Delo 10w30 hdeo for $4/gallon on clearance at Wallmart so that was the next oil test for the 8.1. Kind of fun it will be interesting to see how it does with some of the other oils discussed.
 
Messages
13,194
Location
Maricopa Arizona
Originally Posted by Dudemanmaximus
Yeah I agree. If the 8.1 does great on 5w40 or 15w40 that would be great cause I have a lot of that. I just thought it reasonable to start out at the recommended oil weight and move on up from there plus I did score 2 gallons of Delo 10w30 hdeo for $4/gallon on clearance at Wallmart so that was the next oil test for the 8.1. Kind of fun it will be interesting to see how it does with some of the other oils discussed.
If you can get a 10W30 HDEO at that price I would use it also in a 8.1 it's a good choice.
 

Dudemanmaximus

Thread starter
Messages
26
Location
Michigan
Yep that was one of the best deals I have scored on oil. They only had two gallons on the very bottom shelf with no price indicated anywhere, and at the time I was thinking of trying a 10w30 hdeo in my Dodge and they only had and I needed 3 so went up to the desk where they do auto service and asked the guy if they had anymore so he scanned it in and said "no but these are $4 - dang that's a great deal!". I proceeded immediately to checkout.
 
Messages
901
Location
montreal ,canada
[quote=Brigadier]My dad has a 2002 Silverado 2500HD with that engine. He hauls a huge bed camper with his to AZ and back yearly. It has always consumed about 1qt/1k miles on 10W30, except when he used to run AMSOIL in it. Then he would burn 1qt every 6k OCI. [/quote I assume the Amsoil was also 10w30. Why such a huge difference on the consumption? You're saying he stopped running the Amsoil, if so was it the cost differential? The way I see it wouldn't he have been better off staying with that oil? With whatever else he was using he would have had to use another 5 qts. over that 6k anyway. Hope I'm not missing something here and asking a stupid question. Also what is the sump capacity, I imagine it's a lot.
 
Messages
1,349
Location
Elizabeth. Colorado
Originally Posted by Dudemanmaximus
Yeah seems to be I have one that uses a little oil. There was quite an improvement with 10w30 hdeo so I am hoping 5w40 rotella syn or 15w40 will improve it more. I also am considerin a 10w40 too prolly M1 but I have many gallons of 5w40, 0w40 synth and 15w40 dino in the barn. The spark plugs were nasty and changing them out with new wires made a huge difference. Pulls like a beast now. How often do you change your plugs and wires? I am thinking every 25-30K miles or if it starts to act like a slug.
Around every 50k miles on the plugs, just once on the wires since I bought it. I've had, and have, many big blocks that use 1 qt every 1000 miles, it's not a big deal to me. Really use whatever oil you have like others have said, keep it simple.
 
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