Strange Engine Noise (3.4L)

[JFleury8469]

So I had just finished up fixing the front end on this thing, getting the front struts done and finally getting an alignment, and I left the shop where I got the alignment done, went to get on the interstate and was suddenly greeted by a very loud rattling sound. I'll admit, I was hammering on the throttle a bit so it's probably my fault...

After pulling over to find out what the noise was, I started the engine back up and drove home, all the while the noise (while under power) would get louder the more gas I gave it, which I had to do to get over some of these hills we have here in VT. I should also mention that there is at least a 50% reduction in power now. While coasting at 40mph the sound would almost disappear, but as soon as I touched the throttle the sound would return.

I took video of it on my phone, hoping that someone here might be able to help me out. I just dropped $400 into this, after already having spent $3500 in the time I've had the car (used engine, rebuilding the same engine, etc.) and I'm getting towards the end of my patience with the car... If I can't fix it for less than $150, I'm done for a while and getting a different car. Hopefully it's something small but the sound it makes and power loss that accompanies it tells me that it's gonna be a big bill when all is said and done. Now, with that out of the way, here's my video:


Thanks for any advice!

[350rs]

sounds like a valve smacking the piston to me. try using a automotive stethoscope or a screwdriver to the ear on each valve cover and see if you can tell where the sound is. if you dont hear it there, search elsewhere.

[Malaclypse]

The rocker arms were overtightened the last time intake gaskets were done and the threads have pulled out. This is causing the rocker/pushrod to smack into the valve cover.

Sounds like its going to be the front so pull that one first.

If that's what has happened, a drill... some precision work and a heli-coil kit should get you down the road.

[zukiracer19]

sounds to me like you might want to pull those valve covers off and just take a look ... either your valve is smacking your piston (if that was the case im pretty sure it woulda focked **** up already) or your rocker arm came loose...

[zukiracer19]

Originally Posted by 350rs

sounds like a valve smacking the piston to me. try using a automotive stethoscope or a screwdriver to the ear on each valve cover and see if you can tell where the sound is. if you dont hear it there, search elsewhere.

last time i was doing that... was workin on a mini van... started it up literally a minute later i had oil pissing all over the ground... -_-

[350rs]

i was only thinking if it hadnt completely come apart that or loose that it might just be tapping the piston. Didnt consider a rocker arm. seems more plausible.

[JFleury8469]

Thanks for the suggestions, I'm at work now but when I get out I'll see if I can get a look at it. Would the rocker arm cause the engine to lose power? I know if a valve was stuck there would be no compression in that cylinder and would cause the engine to lose power, shake alot, and idle like crap much like it does now. Can I just get a rocker arm from the junkyard if I pull it myself? If so, I'll go that route as I've never done anything more than move my P/S pump over to replace the cam sensor and I would like some practice before tearing the engine up haha. Thanks again!

[zukiracer19]

if nothing is damaged,,, id just take valve cover off... retorque'm and see if that works... pretty sure you can get to'em without taken the uim and stuff off... and if you do have to pull the LIM off... you can pretty much have it apart in and back together in like id say 2 hours to say the least... i can pull my head off/on and whatnot within that time or less because ive done it so much

[juanvan]

Rocker, rod, spring something internal that is for sure!

[zukiracer19]

well im telling you now... if the spring ****... and that valve fell down in there... that motor would be done... or even if valve was hitting piston... wouldnt take long for something to go... my guess is rocker arm

[JFleury8469]

Well, I tore the front valve cover off... I know what I'm looking at but I'm not sure what something would look like if there was anything wrong,
so I put my phone to good use again and took a video of what's underneath the valve cover, and also took a couple pics of the backside of the
valve cover. Nothing looks like it's banging the back of the cover, and to me, everything looks in order as far as the front half is concerned...
The back of the engine is an entirely different story.



http://i29.photobucket.com/albums/c2...7-28162552.jpg
http://i29.photobucket.com/albums/c2...7-28162542.jpg

I know I should probably suck it up and get a $20 Haynes manual rather than doing a step-by-step teardown on here, but cash is REALLY
tight right now. I really appreciate the help you fine folks are providing me, hopefully we can narrow this down to a few possibilities that
even a newbie like me can attempt to fix.

[juanvan]

You have anything on the back side?
That might be where the sound is coming from.
But all those rockers look good and springs too.

[Malaclypse]

Check the back. I swear you've got a rocker loose somewhere. The noise is less than 1/2 engine speed which means its valvetrain and its isolated to 1 cylinder. In the running wideo the motor was definitely stumbling when the noise occoured so you have compression.

[zukiracer19]

Originally Posted by Malaclypse

Check the back. I swear you've got a rocker loose somewhere. The noise is less than 1/2 engine speed which means its valvetrain and its isolated to 1 cylinder. In the running wideo the motor was definitely stumbling when the noise occoured so you have compression.

This...

Back valve cover will be a pain in the ass, gotta take coil pack and whatnot off... you can do it...

[AaronGTR]

Yeah, it sounds like something valve train to me as well. Gonna have to take off the alternator and bracket, and the ignition module with the coils on it, in order to get the rear cover off.

[JFleury8469]

So I finally got around to pulling that back cover off... Bad news.. Just like you all said, definitely valvetrain related...
The bolt that holds the rocker arm down for the right-most cylinder pulled right out of the head, pics to follow:

Some of the pics might be larger than others, photobucket is having an issue with how I formatted them... Hopefully it gets fixed soon.

Where the rocker/pushrod was smacking into the cover:

Same thing, different view:

The rest of the rockers/valves:

The culprit:

Better view:

Ouch...:

Any ideas on how to fix this?

Another shot of the bolt...


So yeah, I know there was mention of this "heli-coil" kit but I have NO idea what that is and probably less of an idea how to use it.
What are the price ranges for dealing with this? I know buying a used head will probably be much more expensive so I'd rather not
go there... Thanks to everyone for all the help in diagnosing this problem. I used to think tearing into the engine was really a HUGE deal,
but this was actually kind of fun, even with finding out what that little problem was hahaha.

[lastyear4gt]

A helicoil is a replacement thread kit. Esentially you drill out the hole bigger than it needs to be and tap and install replacement threads into the hole. It's quite simple really, google it. Don't be afraid....

[JFleury8469]

Yeah I actually looked it up shortly after. Looks pretty simple. How well would the replacement threads hold up in this situation??
Also, I can't seem to find a place to buy this kit... The actual kit looks like it would have the correct size and thread pitch for the
rocker bolt, but some of the 'kits' I'm finding on Amazon are for certain types of threads, mostly metric coarse thread repairs...

AutoZone didn't appear to have anything, nor did Ace Hardware. The other thing I'd be worried about it getting metal shavings
in the oil while drilling out and threading the hole, is there an easy way to avoid this? Sorry to be a pain, I'm still new at this :\

[zukiracer19]

Honestly, if you already have the UIM off... LIM is just as easy... just use a cereal box or something to put rods and rockers together... and label... I wouldn't want any shavings going in there... is the threads itself inside there stripped also?

[unchained_01]

There is a "how to" on here or GAOC. Pretty straight forward ,threads are 8 mm or 10mm 2000+ has 8 mm so yours should be and look like 10mm I did remove the UIM for more room to the back I DID not remove the LIM. I used a portable 90 degree craftsman drill on the rear bank I used a clean t shirt and duct taped it to the head making a place for the shaving to go and was just very careful removing it afterward Take your time and drill straight Clean the "bottom" tap frequently and don't try to thread it all at once. It's easy and you will save yourself some money Most major part stores carry heli coils , take the rocker with you. I have done 4 of these on 3 different cars and they have all been 99 -00 models and only one on a 2002. So far. Good Luck