Finally getting to the bottom of my engine knock.
 

As some of you may know, my engine likes to tick it's heart out from time to time. A nice steady tick at idle that rises and falls with RPM's. At certain RPM's my truck sounds like a 30 year old washing machine, it's embarrassing and downright worrisome. It comes and goes, is never consistent, and has been driving me insane since shortly after I bought the truck. It's been to the east side Hummer dealer, and most recently a local Chevy dealer. No dealer has even been able to hear the noise, because by the time I get it there, it's not making the noise, and it never does it when it's in for service. However, I have mentioned it nearly every time it's been in for other warranty work so they would listen for it if it started happening.

The Chevy dealer told me any time it happens to come back so they can listen to it. The service writer I know through family was very adamant about "any time".

Today during lunch it started doing it, and was still doing it after work. I took it straight there after work, and the first person that tried to help me pulls the "we close in an hour and all the mechanics are gone for the day". Right. He ended up chasing me into the service bay as I went looking for a mechanic.

I saw one of the techs I've dealt with a couple times washing his bay down and grabbed him to come listen. Long story short, its going to be covered under my 100k powertrain, as soon as I can get it in and leave it with them they're gonna pull my head and get to the bottom of it.

The best part is when the tech looked under the hood, grinned and goes "This is one bad a$$ H3, don't worry about steam cleaning the engine bay before you bring it in, I could care less if you offroad this thing, it's made for it, they wouldn't put it on the commercials if they didn't want you doing it."

He even went as far as to say "I wont ask, so don't tell, but I will tell you this, if it's got a custom tune take it out before you bring it in and we'll get your knock fixed right up. Only reason is because with this level of warranty work GM is gonna want a copy of the program it's running."

Thank GOD for the local Chevy dealer, this issue has been making me lose my mind.

Good news, hopefully the can pinpoint the issue the first time. Mine has a small tick that was driving me crazy and I thought I might have a lifter sticking. Took it to the dealer and they tell me it's the fuel rail I hear ticking. They say it's normal. It is more pronounced in the winter.

Yeah this is definitely not the fuel rail I'm hearing, just to give you an idea of how bad it is, here is a sound file I took today.

http://monstersofcrok.com/uploader/f...9%20165651.m4a

Holy crap, yeah that sounds rough? Are you burning oil as well? Piston slap?

Not burning oil, and piston slap would go away after it warms up, this comes and goes with no rhyme or reason.

The tech seems to think it's a lifter, I guess we'll find out in about a week when they yank the head.

I'm just thankful my PCM tune didn't show up yet or I'd be hosed.

I REALLY want a PCMforless, but this is a perfect example why I'm holding off. My stealership told me if they're working on my H3, and the diagnostic equipment shows an altered tune, it displays a 'VOID WARRANTY' pop-up, and shuts down testing.:eek:

Worse comes to worse you can send it back to PCMforless and they'll put it back to stock. I think if it came down to it and something major happened I would wait and get it de-tuned before going in for work.

If it didn't tie up an extra few hundred bucks, I'd just keep my PCM and buy the PCMforless. That way I could just swap when needed. I guess that's a big advantage of the Superchips type tune.

Hopefully they get it fixed for you this time. Sounds like a lifter problem. Warranty issue is the main reason I will wait to get the pcm tuned on this one.

Went and checked on the Hummer today at lunch. New lifters are in, the tech was getting the engine back together when I got there, all new lifters on both sides. Free oil change and coolant change out the deal too.

On top of all that the tech broke my alternator getting it off, so it looks like I'm getting a new free alternator too! Guess it's my lucky week. New lifters, head bolts, head gaskets, free oil change, coolant change, and an alternator! It's nice to see GM and the dealership standing behind their vehicles, I was a little worried picking up a vehicle with a dead brand, but no worries here anymore!

I got some pictures of the engine with the heads off, I'll throw some up later tonight after I get home from the gym. All in all it looked pretty clean inside, cylinders looked good, no marring in the walls, no excessive carbon build up, spark plugs look brand new still too, so that's good.

All in all I couldn't be happier. Pat O'Brien Chevy in Ohio rocks!