Knocking....

[Nate's Alero]

well, car has always had cold knock, thats the pistons, normal..

it never did this until i changed my oil,


when its cold, normal, knockknockknock....


whatever,

now when i drive it, it sounds great, nice and smooth,

but, when i go somewhere quiet, and free rev it, i hear a dreadful, slight knock....

it goes away when i rev, but when its free spinning down, knock knock knock.... its slight... but its there,

and when i shut it down, and then restart it, knock knock, til i start driving


now, what should i be looking out for? oil can go 4500 miles and be nice and clear... the engine has no sludge,,

i use castroil GTX high mileage, 5W 30, 4.5 quarts, with a fram extra guard oil filter

so, its slight, maybe a lifter? i did seize one and sand it out...

[undersc0re]

I would say try 10w30 first to see if it gets quieter, cheap fix. If it is a spun bearing going bad or similar yiur soon to be doomed! Could be even loose exhaust or sumthin like that.

[tomekbrek]

I had the same problem one time and i used mineral oil 20W-50 (quaker state) and after 5000miles i used it again, peace and quite, it is good oil for summer, but not on winter.

[Nate's Alero]

JEEZ! 20W 50!?!?!

well, the guy at AZ, did something with the rockers, no moar knock

[tomekbrek]

yes, 20w/50 we have not 5w/30
when a car is new 5w-40, after 100k miles 10w/40 after 150k 15w/40 winter and 20w/50 summer and the same when it knocking - it is normal in whole europe, GM dealers says the same... in oder words 20w/50 is the best oil on summer

[Nate's Alero]

wow, that scares me...

[guiguilandry]

lol don't be scared... I use Valvoline VR1 Racing 20W50 in my car too.... but I had my engine rebuilt for race purpose.....

Use 10w30, it will help you on that noise for sure

[Nate's Alero]

cool, i plan on pulling, and doing main rod and crank bearings, new lifter's and rocker's, and diamond forged pistons for no knock!

[lonnie]

I say get rid of the car now...Every week you got a new problem. Cut your loses and get a new ride...or at least used but new to you.

[WhiteV6]

Originally Posted by lonnie

I say get rid of the car now...Every week you got a new problem. Cut your loses and get a new ride...or at least used but new to you.

You call this thread quality control? I call it thread crapping.

[Nate's Alero]

wow, this is really an alero forum.... maybe i like the problems........

well, 10$ can of engine restore fixed her right up, no knock, no issues