ok i bought my car 2 weeks ago and a few times ive started my car and their was 2 knocks from under the hood. i didnt know it needed premium till a week ago so it probably had 1 or more full tanks of regular gas through it so i just wanted to know is it just this or is it something else? its already gone through over half a tank of premium should i just take it to a mechanic and have him do a general check of the car?

 

eh? how many miles on it?

 

you havent even stated what you own.

have you beaten on the car

and knocking is never a good noise, unless you are mistaking valve train, or injector noise as knocks.

 

its a 2007 chevy cobalt ss sorry with 21000 miles on it

 

that thing must have been raged,,,imo

 

it was in an accident but it was inspected and tht was all set

 

i dont think it was the gas, i kno a guy who ran like 3 tank of gas of 89 before he realized he needed premium

 

not to be a dick but, really, how could you not know that regular gas cant go in it? you really shouldnt be driving a sports car if you know jack **** about them. ANY car that has ANY forced induction doesnt run on regular unleaded. period.

Yes, you have run the chance of ruining your pistons. I would highly recommend you take it to a mechanic, NOT THE DEALER, they will automatically say your warranty has been voided. and if i was you, i would continue to put premium in it until it either dies or whatnot. and if it does die, do not tell them that you put regular gas in the car.

commence the standing in a corner, and smack yourself in the head.

 

so i should take it to the shop for a look?

i dont think a tank of regular really did that much

 

ive had a knocking sound on my car sence i bought it brand new but my noise is not coming from my engine its coming from the back of the car i normally hear it about a min or two after i start my car and my car is at idle.

 

is it a ss/sc or ss?? he never said..

 

it says premium recommended not required right in the manual. just thought if it could be anything else and if it might go away with a few tanks of premium

i said 2007 chevrolet cobalt ss

 

i assumed sc..


if its just an ss then fine, it probably runs on 89 just fine. but you couldnt do that with a sc or tc that would be the dumbest thing




so its a 2.4


oh well in that case your fine...god...

 

i thought he was talking about ss not the s/c

 

no its not supercharged i heard somewhere if u put regular in it it may knock so i was wondering if it was just that or something mroe serious?

 

knocking is pre detonation of fuel. they have harmful effects on the pistons and rings. the fuel explodes before its suppose to, making a knocking noise. however your vehicle is not boosted, thus you should fine but i recommend sticking with what the minimum requirements for your motor.

 

ok i heard it 3 times in total twice when i had regular in the tank and once just a few minutes ago if it happens anymore i should just take it to the mechanic?

 

I would run premium, but i dont think thats what's causing your knocking noise. Is it constant? periodic? only there at WOT? only there at idle? be more specific

 

ive only heard it when starting and only three different times i live up north in mass and its been pretty cold outside maybe tht has something to do with it. it is always just 2 knocks.

 

Premium fuel is not a must with any ss/sc. Read the manual.

 

do u think the knocking is because of the gas though?

 

Sports car? Honestly? LOL its a cobalt. The dealer put a full taknk of 89 in my car when i bougt it. It didnt do anyhting.

 

Don't know. Are you sure you hear it under your hood or in the trunk?

 

since it doesnt make the sound every time i start it i dont know ill check tomoro morning and see becuz if its from the trunk i heard about the ghosts in the trunk and thts nothing to worry about. so ill check tht in the morning

 

That happened a time or two with my old Tahoe when I hadn't driven it in while. I wonder if there's some oil leaking past inside the engine somewhere when it's sitting and when you start you have something of a hydraulic lock until it blows out the oil..