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Discussion Starter · #1 ·
Well there was some mobil 1 on sale at my walmart, but they only had 5w 20. I usually run 10w 30, but this was pretty good deal so I got it. Is 5w20 to light to use in the summer time? I already changed it. It doesn't really feel any different just wanting to get your guys opinion on if I should wait til winter to use that weight of oil, because I bought a bunch! :D Full synthetic mobil1 5quarts for $8.00.
 

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i've been using it in my GA 3400 for about 3000 miles. my mostly in town mileage of 22-23 jumped to 24-26. not completely sure if it was all oil or more efficient driving. however, after seeing the pistons from a 3400 that was ticking....well the anti-friction coating was worn off. so i think very soon i'll go back to the 5w-30. not worth the wear for saving a few $$ on gas.

so yeah, i wouldn't use it. maybe in the winter.
 

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Discussion Starter · #8 ·
well I bought 4 5quart bottles of 5w20 so I guess I'll be waiting till winter to use the rest of it. Do you think it would hurt my engine to run the 5w20 I got in there till my next oil change? I mean it doesn't really feel any different than before. I jst don't want to take a chance of hurting my engine.
 

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i've got 3500 miles of summer and several 1/8 mile runs on mine. think you'll be fine till your next oil change. over the coldest months i feel you'll be fine to use the thinner oil--being it's a full synthetic. 5-20 does have better and more friction modifiers than 5-30.
 

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IMHO 5-w20 oil is too think for the motors in GM cars. The 5w20 oil is good on gas because it's so thin, but our motors bearing clearances aren't very tight (especially with lots of miles). The cars that use the lighter weight oils are tighter motors (generally speaking). The thinest oil i'd use was a 5-w30.

also a honda civic hybrid came thru our shop and they use 0w20 oil :eek:
 

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the bearings won't wear as long as you have adequate oil pressure. todays cars have plenty of oil psi and tighter clearances. with the roller valve train, the only surfaces i worry about are the piston skirts. if GM had the older long skirt pistons, i'd stay with the 5-20.
 

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I don't know that much about oil, but I was wondering about what my fiance tells me to put it it. 10w-40. I guess because it has a leak somewhere. Would that oil be good or bad? I don't suppose its been hurting anything, but then, I wouldn't know.

My old red car had many problems and left me needing the grandad mechanic crew to save me several times, so now my fiance hates these cars. The green one has only had minor troubles- alternator needed replacing, the car died in the driveway, and we had a brake line break. Had to fix it in a mall parking lot by putting a sheared off nail head to block off that line until we could get home. Several flat tires, and other than that- nothing major.

But now, every time something is the slightest bit off, or I tell him I heard a funny noise/ something acted weird, he gets upset. He is currently on another crusade to have me sell it and get something else like a Beretta. :sigh:
 

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funny, the Beretta is pretty much the same thing. just bigger and a different shape. i wouldn't go any different than the 5w-30 that GM recommends. it will provide great protection while giving the best mileage.
 

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agreed! ya, NEVER use 5W-20 on a flat tappet cam! hell, now-a-days, even the 5w-30 isn't quite good enough for high performance cams. the gov't is requiring the oil manufacturers to lessen Zinc and another additive for environmental reasons, thus making the oil less slick. this is fine if you have a roller valve train, but over the past few years, there have been complaints of flattened lobes.

i've been using that in my 04 GASE 3400. but after seeing some pistons out of a 3400 with just over 100K miles on them, i'm switching back. the anti-friction coating was worn off causing a tick. pretty sure the guy was using 5w-30.
 
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