So I just got off from work and started my car to go home. Its a 2008 lnf with 70,000 miles. It started fine and I let it warm up to 160 degrees before driving it. Drove fine to my house and then as I pull in the driveway I heard a loud pop and seen something shoot up from the hood. I shut it off quickly and checked the hood for holes. Nothing though. So I checked my oil and it was half filled. I added a quart. Started the car and its making a tapping noise. Waaayyyy faster than the direct injection sound. And when I rev it up it sounds like the tapping gets faster. Sort of sounds like a sewing machine. Anyway what do you guys think this is because I havent drove it since I heard the sound. Valve tap maybe? I dont hear the direct injection anymore, maybe something to do with that. Idk help guys please

 

Any help guys

 

Video of noise?

 

LNF Weird Noise - YouTube

 

Sounds like something in the valve train to me. If that were my car I wouldn't drive it like that.

 

Yea im scared to honestly. Dont want to screw up more than it already is.

 

If you have warranty tow it in. If not pull the valve cover and check your timing chain, lash adjusters, and rocker arms.

 

Warranty done in January. Regardless im going to need a tow I guess

 

What would I be looking for when I pull the valve cover? Would something seem out of place?

 

Look for anything asymmetrical, I would also check your injectors

 

So I dont want to mess anything else up on the car and will probably tow it next week to a shop. I hope its not too bad. But if it is and needs valves, should I upgrade anything while I have it open? Pistons, rods, etc...

 

Pistons, rods? Your gonna have to disassemble it alot more to get to that stuff than you would need to to change a valve/ valve spring.

What did you see fly up from your hood? If you saw something physical, there should be evidence unless, your car had a bird poop on it and you blew off the charge pipe and it hit the hood and the bird poop flew up in the air.

 

^

First laugh of the day. Thanks.

 

Charge pipe must've reconnected itself then. Honestly idk what it was and there is no damage to the hood so maybe it was nothing

 

Blowing off a charge pipe makes a loud scarey noise if your underboost, even partial boost.

That chatter sounds pretty loud but my car sounds the same exact way on a cold start up so maybe the video isnt really doing it justice.

Did you hit something and you saw it fly up in the air? a bird? large bug?

 

I wasn't under boost. Actually was only using the clutch to roll forward in my driveway when it happened. Foot wasn't even on accelerator. My charge pipe is on fine and trust me if your car sounds like this then somethings wrong.

I just started it and moved it up a little in the driveway. Idles ok. But as soon as I went to move it it misfires badly and wants to shut off.

 

Also in that video the car was at 189 running temp so definitely not a cold start up

 

oh thats no good. Did you manage to get the valve cover off and see if there are loose rocker pieces anywhere? Do you have a subbie sound? or just the loud motor. Possible the timing chain guide (edit) broke on you and now your timing is off > causing valve tappage.

Dont run the car anymore, chances are the damage is already done and you will need pistons.


The upper timing chain guide has a noteriety for breaking for some people.

 

yeah sounds like timing skipped =(

 

Just talked to my mechanic...he said it might be that the valve spring broke and the valve is hanging loose. Idk. A gm tech will take a look on monday. It drove ok but I didnt go above 3000 rpm. I will mention the timing on monday. Thanks for your help guys its really informative info on here

 

No subie sound. Just loud ticking motor. Plus my catless downpipe and muffler delete.

 

Just curious if you found anything out?

 

Thanks for asking, but the car has been sitting all week. I haven't found out anymore than I knew last week. Reason being is I'm trying to research these zzp 82# valves and titanium retainers. Anyone know if they're worth it and how they take to our motors? I've had no luck finding a write up on them. Should I just stick to the stock valves and springs? Lastly what about the supertech valves? Any info is good info ans I'm in no rush to have the car back running yet. I want to do it right and upgrade anything possible along the way.

 

Read through this https://www.cobaltss.net/forums/2-0l...-chain-302318/

 

Thank you. Very informative info over there. Still my question is will I run into problems with the upgraded valve spring rates? ZZP or supertech?