99redsilverado

i want to know something.....i have run 10w30 in my truck since i got it, never have noticed piston slap.....truck went to dealer last week for tires, and since it was due, an oil change. they put 5w30 in it because i forgot to tell them to put 10w30 in it. well for the first time in 60k miles i hear piston slap once warmed up.....does anybody else run 5w30 and have piston slap??? what about 10w30 AND have piston slap???

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'99 Silverado 4 x 4
bunch of goodies

dr_of_lovephd

I have heard when they first made the 88-89 pickups GM recomended 5w30 but they had too many cases of piston slap so they told all the techs to start to putting 10w30 in the trucks. That seemed to solve the probem.

I was told about this when I first bought my 89 pickup. The oil fill cover said to put in 5w30, but a mechanic friend of mine told me to never use it or it would make the valves rattle.

tallica_28

i have a 2k silverado with 66k miles and have always used 5w30 and never had a piston slap....even considering that i bought my truck used three years ago....99red maybe it has something to do with the brand of oil the dealer uses and is the dealer the only place that services your truck.....just some ideas

99redsilverado

i do everything to my truck except for tires, i used to have access to a tire machine, so nobody except for me had worked on it... they use chevy oil, dont know who makes it for chevy, but i use NAPA oil, i have used both 10w30 and 5w30, 5w30=piston slap, 10w30=no piston slap....valvoline makes napa oil.

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'99 Silverado 4 x 4
bunch of goodies

tallica_28

have you used napa 5w30 and get piston slap....if not maybe it is the the dealers oil....i use valvoline...don't like the dealers oil they use pensoil

99redsilverado

yes i have used napa 5w30 and gotten slap

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'99 Silverado 4 x 4
bunch of goodies

tallica_28

well then i have no idea....sorry that i couldn't help

skipr

Penzoil has some kind of detergent or additive that turns to parafin (wax type of substance) gums up the valves and lifters.Or they use crappy crude oil (group 1 baseoil stock). So your correct on dislikeing Penzoil.

pies

i am due for an oil change now. i have always used quacker state 5w-30. i will try 10-30 and see if it gets rid of the piston slap. should i be using a different brand of oil???

99redsilverado

with quaker state you pay for the "Q" its still a good oil, but yeah use 10w30 this time and see if it goes away...how bad is your slap now??

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'99 Silverado 4 x 4
bunch of goodies

pies

when its below 50 degree it will knock like a rod was going to come out of the bottom of it for about 2 minutes. above 50 it lasts about a minute and 70 and up it doesn't do it

99SilverTask

Ditto. I get slapping when it is under 60 degrees. The colder it is the more I get. I run Mobil 1 10w-30 Synthetic

BlenderWizard

So, when one has piston slap, what is the piston "slapping"?

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silveradoking

I don't know you guys, but you might want to change the oil filter.....You see....I bought my truck at 60,000 kilometres, and I started using those cheap ass fram filters....And after about 5-6000 kilometres, I noticed the piston slap was getting worse and worse.... then at 80,000 kilometres, I switched to the k&n oil filter.....and no more slapping around....Maybe you guys can try that, and see what happens....I have right now a bit over 90,000 kilometres and haven't heard a thing.....

BlenderWizard

Keepin' mine on the AC Delco

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