I was getting tuned on the Dyno when on a run I heard a noise coming from the engine bay. At first I only heard it at about 2-3,500k. So I thought maybe it was a little detonation. So I told the tuner I heard it. The next run it was the same thing I could hear it but when it was in boost I couldn't hear ****. Then I started to drive home and I could hear it. Then about Fter a mile it felt like my car died and cut back on so I pulled over and towed it home.

Today I finally got around to looking at it and at idle you can hear it clear. When I rev the motor it doesn't exactly follow the rpms as far as the noise goes, so I don't think it is a rod knock. The noise to me sounds like a tin can. Not marbles. I also did a compression check and it's is even all the way thru. The plugs are new and still look good.

I also just took off the vale cover and no loose items or bolts. The sound looks like it is conning from the #4 cyl ont the intake side.

Someone please give me so insite.

Here's a video
http://www.youtube.com/watch?v=GXP9A...e_gdata_player

 

Man that sounds like a spun rod berring. You can hear the Squaling of it spinning in the rod journal at the beginning of the video. Then later all you hear is the tapping which would mask it as a loose lifter.

Curious what is the oil pressure at?

 

Ya I think that noise at the beginning is my alt. Belt, at least I think it is. My oil pressure always starts out high then drops to like 40-20 at idle I think. I'll start it up tomorrow after I make sure the alt. Belt is tight and see what happends with the oil pressure gauge.

 

quit running that motor....drain the oil and check for metal flakes....pull the valve cover and check
you said you did a compression check and it was even....so i doubt its valve related....but that sounds like rod knock to me.
my g/f sitting on the other computer about 5 feet away says "damn that sounds like rod knock" (yes she is into cars like me)

 

Sorry to say, but that sounds like a rod knock. Take the engine apart... Good luck.

 

Yeah, sounds like rod knock. stop running that motor now. And change that alternator belt. Time to work on the block.

 

Damn it looks like I'll be on my back again. This motor was just rebuild about 400 miles ago. New bearings, reground crank, resized rods and new postpone with a bore and hone. I hope they will warranty the bearings and I hope the crank isn't bad.

 

Personally I would never "regrind" a crank unless it was my last option. I would rather replace the crank if a journal is scarred beyond minimal polishing.

 

Well I'll drain the oil today and check the plug for metal shavings. I wonder if I'll need a new crank also. But has been driven less than 3 miles once I heard the noise.

 

Bump

 

I wasnt talking about the alternator... You can hear clear as day the rod berring squalling right after the alt shuts up. You need to pull the pan and pull off all the rod caps one at a time to find which one is having the issue.