Oil for 2004 GM 4.8 LR4 LS

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236
Bought a 2004 Silverado Z71 with the 4.8 and 118k miles on it last year. I've changed the oil and filter three since then, and only put 1k on each oil change, just because the oil change history is unknown to me. First time was Valvoline synpower (had on hand), next time was M1 5w-30 again had on hand. Third time was ST HM syn 5w-30 because at some point it developed seeping from the pan. Not sure if that always was there or started after I got the truck.

Does anybody have any recommendations on oil that might help with the seeping? Maybe the new formulation of Valvoline advanced max life? I don't really know how picky these engines are as far as brands or even weight, other than if it's not driven for a week or so the lifters make noise at startup for a minute or two.
 
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2,209
Location
Muncie, Indiana
GM V8s have never been that picky about oil, so use whatever, Valvoline MaxLife is the the classic goto for high mileage oil, run it for a while and see if it helps, if it doesn't maybe try a different high mileage oil, whether or not it work in someone else's case in the past won't necessarily tell you how it will work in your case, the only way to find out if the high mileage oil will help is to try it, results will vary from case to case.
 
Messages
1,154
Location
Kansas
Drop the pan, replace the gasket, replace pan. Easy job. Don’t just try to use a HM oil to fix it.
 
Messages
172
Location
VA
Cheaper, not really. A new pan gasket is what $20-30? And 10-30 mins of time. :)

but yeah, if the leak/seep is small enough, a thicker HM oil can help stem it.
He stated it's a Z71 which would be 4wd and typically there is a lot more to replacing the pan gasket on 4wd models vs 2wd. I should really know as I basically have the same truck also 2004 but it's a GMC w/ 5.3
 
Messages
1,154
Location
Kansas
He stated it's a Z71 which would be 4wd and typically there is a lot more to replacing the pan gasket on 4wd models vs 2wd. I should really know as I basically have the same truck also 2004 but it's a GMC w/ 5.3
On the older trucks, yes Z71 meant 4WD. And I'm aware of what's involved in dropping the pan but fine, up it to 30-45 mins. :D :p
 

ssspencerjr

Thread starter
Messages
236
He stated it's a Z71 which would be 4wd and typically there is a lot more to replacing the pan gasket on 4wd models vs 2wd. I should really know as I basically have the same truck also 2004 but it's a GMC w/ 5.3
Yes, I'd have to remove the engine guard, remove the cross member, drop the front differential then I can get to the pan. Really wanted to try this before I went through all that.
 
Messages
172
Location
VA
Yes, I'd have to remove the engine guard, remove the cross member, drop the front differential then I can get to the pan. Really wanted to try this before I went through all that.
I've removed the skid plate because it makes changing the oil a lot easier, as you know when you drain the oil it lays on top makes a mess and you can't reach in there to wipe it clean.... overall it does sound like it would take a lot longer than the 35-40 min that was estimated. I love the truck other than the common problems that affects these models, gauge cluster stepper motors, knock sensors, etc.... I would try the HM oil first and then go from there, the Valvoline Maxlife seems to be highly regarded on here. I have about the same miles on mine, I believe it has 116k and I'm running Shell RGT 5w30 but was using PP up until the new Rotella came out. It typically goes through 1 qt between changes and never really found it a big deal as your changing anyways, sometimes I top off in between though.
 
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