Oil for 2002 gmc 8.1

[sleek willy]

The owners manual says to use 5w-30 or 10w-30 and specificly not to use 20w-50 which would be my choice. Whats wrong with 20w-50???
-Sleek Willy

[Havasu Hangin']

I'm gonna go out on a limb and say that they think it is too thick?

[sleek willy]

I've Been using 20-50 or 50w for years in all my toys, quit using 10-40 after my camaro spun a bearing. This 8.1 has used oil since new, now that it's off warranty I'd like to try 20-50 to see if it helps. 10w-30 is like water, just doesn't seem right :idea:
-Sleek Willy

[Havasu Hangin']

I wouldn't be too quick to compare your Camaro to the 8.1. I'm sure that GM engineers have specific tolorances that the require the 8.1 to use a thinner oil (vs. the old days).
The 8.1's have always used oil...the GM boards are full of gripes. I don't think the thicker oil helps...but you might want to search them yourself.
http://www.chevytalk.org/threads/postlist.php?Cat=&Board=UBB11
http://www.gmfullsize.com/forum/index.php?
http://www.gm-trucks.com/forums/index.php?showforum=3
http://www.ls1tech.com/forums/forumdisplay.php?f=21
You can try the 20/50...hey, how expensive can that motor be, anyway? :supp:

[Beer-30]

Ah, the ol' oil topic. I witnessed a Baja 1000 winning Jeep cross the finish line at 5000 rpm with zero oil pressure for the last mile. Rock hit the oil pan and pressure was dropping/fluctuating for five miles. We still couldn't see him (over a mile away) when he said it hit zero. Told him to stay in it. Valvoline was a sponsor and it was running 10-40 racing. The same guy had a car-carrier (1987) with carbed 454. I personally drove that carrier 225,000 miles running 10-40 regular Valvoline. It was still running fine when I left. I have always run 10-40 Valvo until these last several years. Switched to Mobil-1 10-30 synthetic since Cosco has had it. I figure if Callaway wants to run it in a 1000 HP vette, it's good enough for me. It only takes 7 lbs of pressure to keep the average motor alive. I figure my '98 Vortec 7.4 is doing just fine with 20 at idle with 10-30 synthetic. I change it about every 6000 and it looks great. Sure, its starting to blacken a little, but you can still see through it. Not so with the earlier Valvo 10-40. That's the difference in synthetic. The dually loves it. Will be doing the first change on the boat (since I just bought it) and will put the same Mobil-1 in it. Putting Torco racing synthetic manual trans lube in the B-1.
I wouldn't run 10-30 regular, but I see no problem with synthetic. Especially the 8.1. Probably tighter clearances than my 7.4, so there's no reason for any thicker oil. Will 20-50 hurt it? Why would it? It's still oil, right? It will still get into the bearing gaps, but will just be a little slower to get there on the cold mornings. IMO, the 10-30 will always get around in there quicker and will be superior lubrication to any regular oil regardless of the numbers.
my 2 cents.

[BarryMac]

You will lose about a qt every 2,300 miles or so, I had my truck back to the dealer a half dozen times at least to try and fix the problem, GM came back and said that it is perfectly normal for that size Engine and that they wouldn't do any types of repairs. My only conselation to this is I have an agreement with the Dealership, they give me an extra qt to take with me so I'm not out the $3 (whoopy) for the extra qt before my next Oil Change...

[daytona22]

i just bought an '02 2500hd w/the 8.1 - it had 43000 on it when i got it. i got scared the first time it used a qrt. b4 the 3m change, and the last change went 1500 mi. b4 i had to put another qt. in. are u guys telling me they all do it? i was afraid i got a bad motor? do any of u think syn. will do better, or will it just cost me more to keep it toped off?

[Havasu Hangin']

i just bought an '02 2500hd w/the 8.1 - it had 43000 on it when i got it. i got scared the first time it used a qrt. b4 the 3m change, and the last change went 1500 mi. b4 i had to put another qt. in. are u guys telling me they all do it? i was afraid i got a bad motor? do any of u think syn. will do better, or will it just cost me more to keep it toped off?
My '04 8.1 has used oil since day one. I don't think synthetic will make a difference. I just switched to some very durable (non-synthetic) Swepco oil...I'll see if it uses any.

[sleek willy]

I'm glad to hear my motor doesn't burn more oil than usual, I was worried. Guess i"ll continue to run the 10-30, it still seems awfull thin but what the hell. Thanks for the input everyone.
-Sleek Willy

[daytona22]

HH, i looked at those threads but couldn't really find anything that pertained to the usage problem. i got out of a ford150 supercrew w/4.6 because it crapped the tranny at 41000, and ford didn't care. i thouhgt that i was getting into the ultimate troublefree puller w/ the 2500HD 8.1/ali and now i can't seem to keep oil in it. i've never had anything that used oil so it's been a shock to me. i haven't pulled w/it yet. i've got a 22 daytona that weighs 5300 on the trailer, and i hope pulling doesn't make the problem worse. if u can find any moe info on this i would really like to hear it. do u know - does this motor have a pcv vale or not - some say that is the way to fix the problem.

[BarryMac]

HH, i looked at those threads but couldn't really find anything that pertained to the usage problem. i got out of a ford150 supercrew w/4.6 because it crapped the tranny at 41000, and ford didn't care. i thouhgt that i was getting into the ultimate troublefree puller w/ the 2500HD 8.1/ali and now i can't seem to keep oil in it. i've never had anything that used oil so it's been a shock to me. i haven't pulled w/it yet. i've got a 22 daytona that weighs 5300 on the trailer, and i hope pulling doesn't make the problem worse. if u can find any moe info on this i would really like to hear it. do u know - does this motor have a pcv vale or not - some say that is the way to fix the problem.
Daytona22, I can tell you that the replacement of the PCV valve does not fix the problem, they changed mine and the problem stayed the same. I can tell you that in the 30,000 plus miles that I have put on my truck the problem hasn't gotten any worse, it has stayed the same that at about 2300 miles after the oil has been changed I am adding a quart. As I mentioned before GM says that it is not abnormal and they don't plan on doing anything ot fix the problem. When I had the Service Guy looking at it I asked why it was using the Oil, I can't remember exactly word for word but it was something about the Shorter Pistons that they are using in the big block to make more torque/HP??? Or something along those lines, the Oil is seeping by the ring and burning out.

[Dawn Patrol]

The 8.1 does use a quart of oil in between oil changes, mine has for the last 94k miles. I use Castrol 10-40 since it was new. Damn thing still runs Great.

[daytona22]

it shouldn't burn ANY oil - it will eventually cause catalitic problems, and i want mine fixed! i went to the dealer i bought it fron and got to one of the mechanics directly - he says there is a bulitin from gm on this to replace the intake manifold bolts to fix the problem, so mine goes in monday for that. i will keep everybody updated. it won't take long because this is my daily driver, and i do about 600 mi./wk!

[BarryMac]

it shouldn't burn ANY oil - it will eventually cause catalitic problems, and i want mine fixed! i went to the dealer i bought it fron and got to one of the mechanics directly - he says there is a bulitin from gm on this to replace the intake manifold bolts to fix the problem, so mine goes in monday for that. i will keep everybody updated. it won't take long because this is my daily driver, and i do about 600 mi./wk!
Not trying to burst your bubble, they did that to mine as well...

[daytona22]

S@*T!!!! did they try anything else? did it help at all?

[BarryMac]

S@*T!!!! did they try anything else? did it help at all?
The only recomendations that GM had were the Manifold Bolts and the PCV Valve, neither of them helped, I actually have a copy of the Service Bulletin that they put out (customers aren't supposed to see these) and it clearly states that GM found that the 1 quart use in less than 3000 miles, I actually think it stated in 6 Full Tanks of fuel, in my truck is about 1200 miles was normal. If you want to read it PM me your e-mail address and I will send you a copy. The best thing that I can tell you too do is tell your Dealership that you are not willing to fork out the money for a quart of Oil between oil changes,tell them you feel that it is excessive consumption and see if they will give you the quart, that's what I did and I take a quart with me after every service...

[Havasu Hangin']

I heard that GM knows it's the ring package, but won't do anything about it, since it would be too expensive to fix.

[daytona22]

gjb, i don't know how to do a pm, but my email is kandaloro@neo.rr.com. i would ove to see it - how many miles do u have on your truck? what do u pull w/it? does the consumption affect power/pulling/anything?

[dossangers]

my 01 8.1 used a qt every 3500 miles dont know yet on my 2005 dont waste your money on synthetic i changed the oil every 7500 but stick with lower weight oils!

[BarryMac]

gjb, i don't know how to do a pm, but my email is kandaloro@neo.rr.com. i would ove to see it - how many miles do u have on your truck? what do u pull w/it? does the consumption affect power/pulling/anything?
I'll send it on Monday, I need to scan it at the office.
My truck has just a shade over 44K on it, I bought it with 12K and it has been a inconvienence since day one, we pull a 21ft jetboat. The oil use has not effected anything other than I am very careful checking it starting at about the 1,000 mile interval after I get it serviced. Like you mine is my daily driver, when we take it on long trips it doesn't use any oil, it uses it when I do the around town driving, strange, absofreakinglutely but GM is not doing anything to reftify the problem. Like HH said it is a ring problem and would cost GM an assload of money to fix, that's the reason that they say it is exceptable, IMO...

[daytona22]

well at least i won't worry when i'm doing the long runs w/the 22 in tow. we go to lake norris(460 miles) and ohio river(120 miles) and if it doesn't use oil then i will be ok w/it. if it uses oil on short trips, but not long, then the block/pistions must need to get good and hot to seal everything up. i can't belive that GM doesn't realize that stuff like this will cause regular customers to go elsewhere the next time. how much does that cost? not to mention all the bad press they get from all of us when people ask us about our trucks and if we're happy. it seems that they make plenty on these types of vehicles, and when they quit selling, that is when the cost to them will be the grestest!!!!!!