So I go out to my cobalt (07 SS SC) and fire her up to run some errands. As soon as I start it up I notice the engine sounds louder than normal, kinda like an exhaust leak at the manifold. I give it a min or two to warm up, still no change. I pop the hood, oh boy, this doesn't sound good:

2007 Chevy Cobalt SS Superchaged loud engine knocking noise - YouTube

I checked the oil level. As soon as I pulled the dip stick out I could smell fuel, lots of fuel. I wiped the dipstick on some paper towel and the oil appears thin, almost runny, and smells very strongly of gasoline


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I haven't driven it for a few days, the last time I did it seemed normal, sounded fine.

So, any guesses as to the problem? My usual mechanic 1. hates cobalts and 2. is crazy busy so can't get it in for a while. I'd really hate to take this to a new shop for fear of getting screwed

-Jamie M.

 

gas in the oil=bad rings

 

I know the answer to this questions is probably no, but do "bad rings" make "clank clank" noises too?

-Jamie M.

 

Jamie,
I'm sorry to read about the oil and gasoline situation you have with your Cobalt at the moment; it looks like you may have a lead from nwss, and I hope that you're able to find a resolution! If you decide upon working with a dealership, please let me know as I'm glad to be of assistance along the way.

All the best,
Sarah
GM Customer Service

 

Thanks for the quick reply Sarah.

I've had some really bad experiences with two local chevy dealers when I purchased my 2004 Grand Prix GTP compG brand new. I purchased it from Gus Brown, had it serviced there as well as Nurse. It got to the point I called GM customer service and they sent out a technician to Nurse to look at my car, found out it was a cracked rear brake line nut from being over torqued at the factory. I got a recall notice a month or two later (for the same issue), so I was not the only one. It took me NINE trips to the dealerships (five to Gus Brown, they told me to quit bringing my car there, four to Nurse including the special tech visit from GM).

It just seems that the dealership... I don't know, don't seem knowledgeable? Why was the GM tech able to figure out the problem in 20 minutes, when I had been without my car for weeks prior to that, always with "we were unable to recreate the problem"???

If there is a particular dealership close to me (Whitby, Ontario, Canada. L1N 5L4) that you would recommend I would be open to suggestions

-Jamie M.

 

when my egine took a crap on me at 110mph (blower seized) huge cloud of black smoke motor didnt turn over and i didnt want to even try to turn it over smelling gas in the oil so i just fixed the blower and did some motor work =D. my buddies lsj finally went poop also and smelt gas in the oil and was due to bad ring but he drove his car around for awhile slowly haha no noises tho just slow as ****.

1.do a compression check
2.drain your oil and look for metal
3.do you have the new timing chain tensioner? if not it could be the timing chain
4.take off the oil pan and look up for something that isnt right or metal in the oil pan
5.aftering doing so get back on here and tell us what you see.

 

1. I don't have the tools for a compression check.
2. I can do that.
3. Unknown, I've only purchased the car recently, I have not changed it. The car has 120,000km's on it now.
4. Will do.
5. Will do.

Thanks for all the help. I've already put some money into this car (brakes, suspension), I'd like to keep this car.

-Jamie M.

 

i hate it when problems like these occur

 

My friend said his Cobalt was making the same noises and the dealer replaced his cam chain tentioner under a recall???

Any more info on this? Sarah?

Getting more info....

Gasket: 24435052
Seal: 12609467
Tensioner: 12608580
Bolt: 11589123
Chain: 24461834

-Jamie M.

 

cam chain tensioner, or the Supercharger coupler...

 

Thing sounds like a Diesel lol. Definitely could be the supercharger going out.

 

65.00 at sears. You get a compression test kit with adapters and what not. Ive used mine a few times and i love it (albeit, i did pick mine up for about 40 bucks, but thats b/c i got it on sale, at a special event, using my dicount when i worked there:P )

I hope you get it fixed

 

GM told me not to attempt the repair myself, because my warranty recently expired, they said take it to a stealership and pay them a bunch of money to diagnose the problem and then they'll tell me if they'll pay for any part of the repair (probably not). I'm sure they tell everyone that

Sounds like:

Crazy noise: Cam chain tensioner. Wants $450 in labour and $250 in part to fix.
Gas in oil: Cracked piston ring. $1250 in labour and $16 in parts.

-Jamie M.

 

that sounds exactly like my LSJ did when the timing chain tensionser failed.

 

Yeah, in the 27 people who PM'd me videos of their failed timing chain tensioner, they all sound the same as me

If there isn't a recall on this yet, there SHOULD be. I smell the same intake manifold gasket lawsuit coming up

-Jamie M.

 

haha just buy the 2nd gen timing chain tensioner for like 68$ and if you have oil in your gas you have more problems then just a timing chain tensioner lol

 

Yeah, GM tech on the phone said broken piston ring, quoted $1250 labour and $16 in parts for the broken piston ring, he said either that or change my oil every 3,000km's and hope for the best lol i think.

You got a part#? Local GM dealer won't look **** up without a part number

-Jamie M.

 

Ecotec Timing Chain Tensioner 12608580

dont deal with the stealerships unless its warrenty work.

 

Thanks for the link

I wasn't aware that it might be the actual tensioner that's the problem?? I thought the tensioner just pushes on a guide that pushes on the chain, and it's the guide that's worn out, not the actual tensioner??

If this isn't how it works please excuse my ignorance

-Jamie M.

 

If hes smelling fuel then its definitely not the tensioner. Doing a compression test will tell all

 

Woot! "Your order has shipped from Crate Engine Depot"

Lets hope that solves at least the crazy knocking noise.

Then I'll worry about the cracked piston ring

-Jamie M.

 

Ok, so I got the new timing chain tensioner today. Was looking over the instructions, it says it's supposed to be supplied in a fully compressed state?

I measured mine, and as far as I can tell, it's not:


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I can push the small piston in by hand, but it doesn't seem to have any type of lock mechanism to hold it compressed?!

Why can't you just install it in its uncompressed state, the little piston rotates easily, can't see it getting bound up when screwing it in. Would save having to remove the top engine cover too!?

Any ideas?

Thanks!

-Jamie M.

 

Nobody? I'm going to attempt this tomorrow, would really not like to thread it in expanded/active if it's going to cause any problems!!!

-Jamie M.

 

Alright, old cam/timing chain tensioner is out! For future reference, it needs a 32mm socket (I had to go buy one).

Has a totally different end than the new one:


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Yummm sludge:


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Is that an o-ring on the old one?? New one not designed for one??


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Alright, here goes nothing. Installing timing chain tensioner without a) removing the top engine cover, and b) without it in it's compressed state! EEEEEK!!!

I will video the first start up, in case all hell breaks loose

-Jamie M.

 

I got the new timing chain tensioner in, but it didn't seem to help the problem much Seems a little quieter than before, but tough to tell.

2007 Chevy Cobalt SS Supercharged loud engine knocking noise, brand new cam/timing chain tensioner - YouTube

I guess to the shop it goes

-Jamie M.
(P.S. It wasn't very difficult to put in, in the uncompressed state, basically just turned it so you could feel when the piston "cup" was lined up whatever it presses against (i.e. the tensioner sits farther in, when you start to turn it, it gets pushed out, find the spot when it's furthest in = cup lined up). You have to apply quite a bit of pressure to fight the tension, and trying to get the threads started while doing that is a little tricky, but not too bad with two people.)