did you check to see if you had any broken rockers or anything when you took off the valve cover? It sounds like a really loud valvetrain tick. How's the exhaust sound, normal? Any smoke or anything like that?

 

Never took the cover off. Exhaust sounds normal, no smoke or abnormal smells.

-Jamie M.

 

You can replace the chain tensioner without taking the valve cover off? didn't know that. I would say take off the valve cover and look for broken parts. It's not too difficult of a removal.

 

Yeah, it's a bit of a bitch to install because you're fighting the tension, but not too difficult. I couldn't find instructions in AllData to remove the engine cover, so I didn't attempt it.

Can I run the engine with the engine cover off?

I'll take it off and take a peek inside.

-Jamie M.

 

if you need a how to, it's part of this

https://www.cobaltss.net/forums/how-...sioner-276244/

 

Wow, thanks for the link!!! How did people damage their engines by not installing the tensioner correctly?

I'll go pull the cover off now. And I answered my own question, I though it was just a cover, not the cover to the guts of the engine, lol.

brb

-Jamie M.

 

if the tensioner isn't installed correctly and the chain slips or the timin chain jumps a tooth, you can throw off the timing on the motor and severely damage the motor.

 

Yikes! I hope mine didn't skip a tooth when I pulled out the old one! As far as I can tell it was totally seized, the old piston doesn't move at all! The engine started and idled normally so I assume everything lined back up when I put in the new tensioner!!

I'll check if the timing chain is slack when I take the cover off, make sure the new tensioner is doing it's job!

-Jamie M.

 

ya if it's running ok it's fine. You would have noticed already.

 

That's good news

I wasn't able to get the coil cover off. It's a T27 torx bit, I stripped the first one I tried. I grabbed another bit, brand new out of a set, and tried a second one, stripped it too. I sprayed all the bolts with PB blaster to hopefully free them up while it's being towed to the shop

-Jamie M.

 

Ok folks, update. So I took it to my usual mechanic who "doesn't work on Cobalts" and he drilled out and removed all the seized cover bolts, etc. Gave it a quick look and said "everything looks fine, take it somewhere else", lol.

So I had it towed to an engine rebuilder. He took the engine cover off (appreciated the new hex head stainless steel bolts covered in ultra copper anti-seize compound), gave everything an inspection, pressed on the cam chain and it was slightly loose. He pressed it harder a few more times and "click" the chain snapped tight! WTF?! We bolted it back together and fired it up, NO MORE NOISE!

Somehow, when installing my new cam chain tensioner, it must have become stuck in the "compressed/inactive" state

Problem solved. I really wanted to get a look at the cam chain guides, but oh well, project for another day.

-Jamie M.

 

You sir sound like you've dodged a bullet

 

Don't forget I still have gas in my oil and it still drinks more coolant than it does fuel

One problem solved, cracked piston ring and mysterious coolant problem to go

-Jamie M.

 

If I remember correctly the tensioner is in a compressed state and when doing the install you have to tap the chain to release it.

 

Yep, but mine arrived in an uncompressed state and I didn't have the tool to compress it. I verified this by measuring it's length, confirmed in "AllData" as being released/uncompressed.

-Jamie M.

 

Reading>Me

 

Oil smells like gas and your car is drinking coolant sounds like a much larger problem. I would say something along the lines of Head gasket/piston rings/sleeves etc....I hope thats not the case but you never know. My engine was putting oil on two spark plugs. I pulled the valve cover and found my o-rings were messed up. Changed that and no more oil. Hope you get it figured out and it doesn't cost an arm and a leg. Does your car hesitate under acceleration or seem weird in any way while driving?

 

Pulls like a freakin tank. Routinely bounce it off the rev limiter. Generates full boost. Never ever even one hiccup as far as performance goes, just likes to drink coolant and pee gasoline into the oil.

I'll keep a close eye on things, if I get a service engine light or I notice a large loss of performance she'll go in for a tear down.

-Jamie M.

 

Do you have a dual pass? Check the O-rings on it. That could be your coolant leak. Also check your oil. Drain it all and see if any coolant comes out with it. My headgasket blew so bad on my stock engine that when I pulled the dipstick when removing the engine, oil and water over flowed out of it. I drained the oil and it started out being oil then when the oil stopped the antifreeze started, lol.

 

No dual pass. No coolant is leaking outside the engine or into the oil. I've changed it twice just to make sure.

-Jamie M.

 

Well, I can tell you this if theres no external leaks...its either your heat exchanger, headgasket, or sleeve(s). Go grab a compression tester already! Lol

 

So what happened after all?

 

The shop took my engine apart, found the tensioner hole was totally coated in hard sludge. He ran a snake/brush through the hole, put the tensioner back in, fire up the engine and the noise was gone

I've driven it about 1000km but now I can hear the cam chain making a tad bit of noise on cold starts, so I'm sure she's going to need some new chain guides or something.

Still drinks coolant, still puts gasoline in the oil.

-Jamie M.

 

Hmmmm.... That's weird... Do u atleast have a clue of what's causing that?

 

The mechanic said that when the old tensioner failed and the cam chain was slapping around in there it probably chipped a guide or wore them abnormally. He only took the top engine cover off and ran a camera in the tensioner hole, so the guides and chain weren't specifically checked.

-Jamie M.