20W50 in a 6.0 Vortec

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my buddie's dad drives a 2001 2500HD chevy with the 6.0, i asked him the other day what kind of oil he runs in it. he says 20W50, i thought he was joking but he says hes serious. the truck is closing in on 200,000 miles and runs fine. what would be the negative and positive aspects of running 20W50 in it?
 
I would think he's probably wasted a couple of hundred dollars in gas over the 200 K miles he's driven, due to increased frictional losses of the heavy oil.
Pros: can't think of any
 
I really can't think of any benefits. I can think of a new negative effects... fuel efficiency, harder to find oil, harder starts, Is 20w-50 part of the API service spec for this engine?
 
Wow... 20w50... that's quite a bit thicker than the more than likely 10w30 its supposed to run..
 
i think its 5W30 the recommended viscosity for the 6.0. i tried to tell him it isnt doing any good by running the 20W50 but he doesnt really care lol
 
my dad also has a 2500 hd with the 6.0 v8 all he has ever used is 5w30 castrol edge it uses no oil and he has had some heavy loads that he has pulled it runs great mpg is not that good though
 
Originally Posted By: mobilaltima
i think its 5W30 the recommended viscosity for the 6.0. i tried to tell him it isnt doing any good by running the 20W50 but he doesnt really care lol
He seems to be not doing any bad. 20w-50 in louisanas temps makes the 20w part fine.
 
I embarassed a shadetree mechanic last weekend.. the customer came in to pay for oil for the 6.0L Yukon.
the mechanic, which I've dealt with before shows up with mobil special 20w50 and a bottle of lucas oil sludge, and a protec (wix B filter) and to top it off.. STP Gas treatment (which is [censored]).

I got caught rolling my eyes. the customer asks me what the problem was and I said nothing. Just that engine shouldn't be running such a thick oil, especially with the lucas. and I explained what it really way. the mechanic comes back and the customer questions him and we get into a debate.
in the end.. I'm not the mechanic. I said, no.. but you're putting a 140wt oil thickener with 20w50 oil in an engine that wants to see 5w30. the customer looks at the mechanic and the only response was.. there's 104,000 miles.
the customer tells me that he's very good and has a great reputation within the community. and I said.. that's good for you then.
 
yea, it amazes me how many people are still running heavy weight oils, ontop of STP Oil Treatment, or Lucas Oil Thickener, in say, a Toyota Prius!

One time I went to one of these Pennzoil Quick Lube joints, self-standing in a gas station parking lot, etc....it's own covered/single-garage building, and all the dude had on tap was 10W-30 and 20W-50......I was like dude really? This is 2010 (at the time), most vehicles are specing 5W-30......and then he tries lecturing me about the "heat" being so bad here in FL, all cars needs 10W-30.....etc, lol.

And this guy is allegedly "ASE Certified" (at least the logo is on his building, and on his [censored]....).
 
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STP use to be all the rage back in the 70's. And had those way cool car stickers. I used it in the late 70's and early 80's in a couple of Subarus. Poured like molasses - which back then I thought was a good thing.
 
Originally Posted By: ahoier
yea, it amazes me how many people are still running heavy weight oils, ontop of STP Oil Treatment, or Lucas Oil Thickener, in say, a Toyota Prius!

One time I went to one of these Pennzoil Quick Lube joints, self-standing in a gas station parking lot, etc....it's own covered/single-garage building, and all the dude had on tap was 10W-30 and 20W-50......I was like dude really? This is 2010 (at the time), most vehicles are specing 5W-30......and then he tries lecturing me about the "heat" being so bad here in FL, all cars needs 10W-30.....etc, lol.

And this guy is allegedly "ASE Certified" (at least the logo is on his building, and on his [censored]....).
Maybe the mechanic may know more about engines and oils than lets say a sales associate. You know just from years of working on engines and seeing the insides of many engines. Just thinking.
 
Well, I use Mobil 1 20-50 in an old Cadillac El Dorado with the 4.5 engine. My gas mileage does'nt suffer noticeably. Those old Cad engines suffer from a front main bearing knock (built in) which is not life threatening. But, the heavier oil sure quiets them down. John--Las Vegas.
 
Can't imagine 20W50 unless it has some serious issues. I've used 10w40 in my old Chevy for years and have not seen any loos in economy, but hey it has 207k. I also use 1/2 qt of the Lucas at every change. Old 305 never uses a drop of oil. My wifes Mustang would burn a little oil getting close to the 6k mark on the oil, using 5w30, then went to 10w30 Amsoil and at 10k, level was full. But I'm in Texas where as of now, its 102 during the day. Thick oil vs. thinner, I see pro's and con's but it mainly boils down to personal preference. If you take care of your car, change the oil, whether thin or thick oil, it will last.
 
20w-50? Did it have a BMW M engine in it?

Unless he tows a boat down to Mexico during the summer, there's no need for it really.

If he's worried about his oil not being thick enough, just about any 5w-40 will fit the bill on just about any non-euro car. Mobil 1 5w-40 turbo diesel and Shell Rotella T6 are perfect examples-PLENTY of viscosity, and enough additives so that it will stay that thick.

Personally, they need to come out with 70 grade oils again so all these idiots wipe their cams until they're perfectly round.
 
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