Oil Viscosity question

[Travis Whitaker]

Just got my Sierra back from local garage. Below is the work they did ( had a lifter collapse on cylinder one)on my 2008 has 203,457 miles. My question is the owner of the shop( an old drag racer) said they put 20w50 when they did the oil change ( due to high miles ) that seems like way too heavy a weight? Am I right? Thanks, new to the forum.

Edited February 11, 2020 by Travis Whitaker

[CamGTP]

Yeah, it's a bit heavy.

 

That's the stuff oil classic cars run or engines with larger clearances.

[Black02Silverado]

Yes, that is not recommended.  It will run just not what the engine is designed for.  For your locations and the miles you could go to a 10w-30 year round. 

[Travis Whitaker]

That’s what I figured, overkill. Thanks 

[JimCost2014]

Am I missing something? I see 6 quarts of 5W30, but do not see the 20W50 on the invoice.

[davester]

Maybe they just charged him for the 5w30, but put in 20w50?

[mookdoc6]

Is she quiet?

[SunShine01]

Funny

I’m a used car wholesaler for years. I’ve always owned Chevy. In the hot summer months I always, since maybe 1980 ran 20/50. First it was Castrol GTX, then since maybe 1990, Valvoline Racing oil.

Winter I go same, but 10/40.

Synthetic made my 1998 Tahoe rear main seep.

My hunting truck is a 2005 Tahoe Z71. Bought it with 26k back in 2011 when I sold the 98 Tahoe.

All she’s seen over and over, few exceptions, Valvoline Racing oil conventional 20/50,,,10/40 in winter. She’s @ 150k now. Uses no oil, leaks no oil. She seems to like it and I swear by it regardless what GM calls for.

Why ? GM would love to sell you the next truck. Protect your moving parts with good lubrications. Let the Mobil 1 boys buy the next $55,000 Tahoe, not me.


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[Larry Young]

When I bought my GMC Sierra 2002 with 98,000 original miles one owner I switched to synthetic mobile 1 10w 40 because I live in Texas and it gets very hot so I went a little thicker and our winters don't get very cold I immediately noticed temperature lowering not to point of being a problem and noticed higher oil pressure as well and could tell it ran better my buddy had a 06 Z71 and has ran this in his truck he is at 378,000 Miles and still runs great with no internal work done except replacing gaskets where he had a leak I highly recommend running this but to each is own 

[sefiroxx]

5/30 was introduced to improve mpg at a sacrifice of oil longevity. Not a problem if you change your oil.

But, as the engine runs and runs, and wears and wears, the bearings and guides will wear.

If you have ever had a chance to plastiguage an engine before and after, you can see first hand the wear effect.

A thicker oil will help to fill the wear gaps.

Scoop, run spec on new engines to obtain the mpg and minimize wear. A heavier oil in new engines would increase wear - like making a 50k look like it has done 100k

Getting over 100k, start switching to heavier oil. You'll loose a fraction of mpg, and drive the wear is already there, the thicker oil will help keep bearings and guides seated, reducing the chance of wear from rattle and tick.

[Colossus]

Interesting... What properties to the oils for higher millage engines have in them?  Costco now sells their own branded badged full synthetic 5w30 and now sells Mobil-1 5W30 full synthetic for "high millage" applications.  No more regular Mobil-1 full synthetic regular. 

[sefiroxx]

More detergents and more seal protectorants.

[Grumpy Bear]

7 hours ago, Colossus said:

Interesting... What properties to the oils for higher millage engines have in them?  Costco now sells their own branded badged full synthetic 5w30 and now sells Mobil-1 5W30 full synthetic for "high millage" applications.  No more regular Mobil-1 full synthetic regular. 

Seal swell. 

[Thomcat]

Forget what an old worn engine in this condition should run on.....the question is what oil should 8 brand new AFM cylinder lifters that were installed should run on.....I suspect they'll function best on the original oil indicated on the filler cap

[Lsxtrucker]

My father is guilty of the same thing. Putting 20w50 in anything with over 100k. Him and I had a argument about it. He's a tech, a good one but old school. Gen 1 old school. If she's running quiet, like a previous poster asked maybe just do your next change a little sooner and stick with synthetic and factory recommended viscosity. If it bothers you swap it out. Mine has a little bit less miles (160k) but I will still be running 5w/30 synthetic at those miles too. I've read varied opinions on the effectiveness of high-mileage formulations, other guys swear by it. Personal preference really. Using a trusted brand and the right viscosity should be at the forefront. Needless to say it's really hot here I'm in South Florida. 

 

Not sure if you're aware but Chevrolet has a special going right now for $49.95 for a 6 quart Dexos 1 Full-Synthetic oil change with Delco filter and tire rotation. Goes till near the end of April this year it's nationwide. If your set on getting that oil swapped out and don't want to change it yourself or are unable for some reason this might be a good option. Not a bad deal. 

Edited February 24, 2020 by Lsxtrucker
Typo correction