GMC Envoy oil requirements

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Jan 1, 2003
Houston, TX
The wife and I are picking up her new vehicle on Wednesday, an 04 Envoy SLE with the 1SB package. I wanted the SLT 1SC, but didn't want to pony up the extra $100/mo. She even picked out a black one with the high polished wheels. Just what I need, another black vehicle to keep looking great. [Smile] I did a search on the few threads here on the truck and am very happy to hear such great things about that engine. My question, as you would expect, revolves around the oil of choice. It looks like both Amsoil and Mobil 1 (10W-30 in both cases I think) gave excellent wear numbers. I have some Amsoil ATM sitting around along with some GC and even some S2k 0W-30. I plan on doing an oil and filter change at 1,000 miles, but don't know what to toss in there. Also, is there an oversize filter option? The wife is much more gentle on cars and engines than I am and I imagine that any of the above listed oils will be fine. I just wanted some additional insight to verify my thoughts.
If that engine is calling for a 5W-20, I'd go with the 5W-30 M1, as it is close to a thick 20 weight.
The Vortec 4200 is very smooth refined motor with lots of topend gettyup but the only thing that I really dislike is it's lack of lowend torque. DOHC motors are known for this as they love to rev but it's really a dog until above 2500rpms where it comes to life. Any of the above mentioned oils will work great in this engine. It's got a big 7qt sump capacity so the oil should not be stressed to badly. The standard filter is a Wix 51522 which is what us LS1 guys also use as a longer filter. There's no room for a longer filter and I think the standard one is large enough to get the job done. The 4200 I6 is specd for 5W-30 as most other GM engines. I've been running Chevron Supreme 10W-30 in mine along with a SuperTech ST3675 filter and its very smooth with this combo. BTW This engine has a 10.0-1 Compression Ratio but still only requires 87 Octane. HTH
I'd strongly recommend running 4000-5000 miles before switching to Amsoil in ANY gas engine. You really want to wait until the oil consumption stabilizes before using a PAO/Ester synthetic. I'd run a batch of petroleum oil for 3000-4000 miles after draining the factory fill. I know that Mobil has different ideas about this issue, but I think they are simply wrong. My experience over the past 26 years shows that if you run the engine for 5000 miles on conventional oil, then switch to Amsoil, that oil consumption is nil after that. I'm sure this engine calls for a 5w-30 year round. Since this is a DOHC design, the thinner the better to control valvetrain wear on cold starts. I'd use up the Amsoil 10w-30 by running it for the six warmest months of the year, but either of the 0w-30's would be better after that.... I believe this motor has a 7 quart sump, so long drains should be pretty easy to do ..... Tooslick
Originally posted by Schmoe: If that engine is calling for a 5W-20, I'd go with the 5W-30 M1, as it is close to a thick 20 weight.
I don't believe any GM product yet has ever specified 5w20 as the recommended oil.
Thanks for the replies on this so quickly. I hope that this engine is as good as everyone makes it out to be.
I hope so too, my daughter just bought one and it now has 900 miles on it. I do have a co-worker who, believe it or not, had a piston break in half on his 2002. GM paid for the motor and he paid for the labor. It was out of warranty due to excessive mileage as a result of his long daily commute. Not sure what to use yet either, but I have been using Amsoil in my other cars with very good results so I will likely just stick with ASL in the Envoy as well. (If you can't tell, I will be chaning my daughter's oil for her [Wink] )
Typical 5w30/10w30 GM engine. Just to warn you the engine takes more than 6 quarts of oil and the dipstick is useless. -T
I'm also looking for good options for this truck. Being a GMC truck, I'm sure there are a ton of things available for the truck. There were no factory running boards installed, so I think that will be my first step.
T-Keith, can you explain what you mean when you say it takes more than 6 quarts and the dipstick is useless? Any other GM engines that fit this category?
I think the spec is 6 quarts plus filter, check your owners manual. The dipstick is one of the new style Ford likes to use. Braided metal cable with a textured plastic cylinder on the end. New oil doesn't show up on it well, as the plastic doesn't allow it to bead up. It often shows different on each side of the stick also. You'll see. [Cheers!] -T
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