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do you guys think this is a regular diesel engine knock, or an abnormal engine knock?
the engine is warm in this video

http://www.youtube.com/watch?v=8caC8aH642g

you may want ear phones to hear it well

I will post a video of it when its cold when I have my ipod, and time before I have to get somewhere...:D
 

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It is definitely louder than my jetta without engine cover. It seems to get louder when they hit the pedal,(knock)that is. My car idle is smooth in comparison, no where near as loud. Thats just my 2 cents.
 

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It doesn't seem loud to me but I've only heard bad knocking where the engine is really thumping. If you search youtube you'll see what I mean. I wouldn't be able to hear a light knock if there was one there.
 

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You've got that wierd noise thing going on like my mates vw sharan, it almost sounds like there's to much low end noise coming back through the airbox or something. Apart from that it sounds pretty sweet and I found my car sounded more like that after cleaning the inlet manifold etc, before that it sounded more muffled.:)
 

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Discussion Starter #5
yeah i really think it is low end noise...
i've heard it for a while. it was just hard to distinguish between it and the bad dmf. now that i have a smf, here it is :D

but if its a bearing, there isn't much to do about it except tear it down and do a complete rebuild right?
ignore the noise and run it till it quits, or gets too loud rather?

dad seems to think its just regular diesel knock
but he hasn't really listened to many other tdi's other than his power stroke :annoyed


here it is at cold start. its a little more evident. outside air temp was about 45ºF at start up.

http://www.youtube.com/watch?v=_ejtZtATohc
 

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I suppose if you're really concerned you could drop the oil pan and get a look at the bottom end bearings that way but maybe it's just having a smf and thanks for the toot:D
 

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Discussion Starter #8
I wasn't gonna mention the 'toot' in hopes that you(Seatman) would!
:laugh:

so, on my next oil change i'll pop that pan off (and maybe replace it since it does have some fine cracks in it:panic:)

who thinks i'll see bearing play?
its kind of a fun thought
rebuilding a tdi engine
money might be an issue.. so i'll start saving now! :eek:
 

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It sounds a lot like more than regular diesel knock to me as well..

You just had the head off of this car not too long ago, did you do any piston protrusion measurements while it was off?

pulling the pan sooner rather than later is a wise and inexpensive suggestion.

waiting until it fails is only going to cost you an entire engine, rather than some bearings and bolts. it is very pronounced on the cold start video.

how long was the failed DMF on the car? was it making a lot more racket with the DMF and its reduced noise now, or is the noise about the same as before the failed DMF was replaced?

can you feel any thumpy thumpy when you are engaging the clutch for first gear? then no more thumpy the rest of the gears? or do you only hear the noise and not feel it thru your feet on the clutch pedal, or can you also feel this thumpo thru the floor of the car?

your engine is also moving around a bit on the cold start video at idle. have you replaced any of the 3 motor mounts? (engine, trans & dogbone) the car is almost 14 years old...
 

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yeah...

When we had the head off, and the number two and three pistons were at tdc, the number 3 piston sat lower than the number two piston. in other words, the protrusion of the number 3 cylinder was noticeably(visibly with no measuring tools) less than all three of the other pistons.... I'm concerned about it. we tried to physically wiggle the pistons up and down and side to side by grabbing them with our hands and shaking them but could feel no movement in any. we also checked for any time the number two piston moved while the number three piston stood still... never happened. they have synchronized movement. its just that the number 3 piston doesn't protrude as much as the other ones... it protrudes, but only like two thirds as much as the other ones. I measured all 4 protrusions, and 1, 2, and 4 were the same within a thousandth, but the 3rd one protruded less. didn't write measurements down... stupid on my part... but I cleaned the pistons and block before I measured them. and I do think I remember there being a difference of almost a tenth of an inch. The three pistons (numbers 1, 2, and 4) read within a thousandth of each other and the number 3 was much less... like I said, maybe a tenth of and inch... which translates to about two and a half mm.

The failed DMF was on the car for quite a few thousand miles... started screeching maybe 20 or 30K ago.. I think it was making LOTS of different noises with that bad dmf on there so its hard to say what they all were.:annoyed total bad noise DEFINITELY went down after the dmf replacement though. i've got a video on my youtube channel of the bad dmf noise here is the thread
http://www.youtube.com/user/Crazyred0713?feature=mhum#p/u/4/75RdFV4Ya7E


--"can you feel any thumpy thumpy when you are engaging the clutch for first gear? then no more thumpy the rest of the gears? or do you only hear the noise and not feel it thru your feet on the clutch pedal, or can you also feel this thumpo thru the floor of the car?"--

thumpy thumpy... when the dmf failed yes. I could feel it in the clutch pedal every time it 'hit'. now? no. smooth as silk i guess. I could also feel the dmf in the floor, but now with the smf, again smooth as silk i guess

none of the mounts have been replaced ever. I've wanted to for a while but haven't had just cause. they seem to be in good condition when it comes to weather wear... no black comes off when you rub your finger across the rubber :) but i guess that doesn't mean the rubber hasn't lost its... perkiness

sorry about the 'novel' you had to read :D
it was a slice and dice of a couple older posts there at the beginning
 

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do you know of any history of hydrolock on this engine? or did it have a runaway on its own turbo oil at one time?

with the loss of compression you must have on the #3 cylinder since its so much lower than the others, that would make the car idle rough, and make the different noises every time the #3 cylinder fires. I would say that you have found your issue.

you need to do a compression check and will likely find that #3 is reduced compared to the rest of them. once you do the compression check to confirm something is amiss with that cylinder, pull the oil pan, and with a good strong light, check out the rod for bends etc, then pull the bearing cap. my guess is that you will be looking to replace either a bent #3 rod, or if you are lucky, only a bad #3 bearing and not have to remove the crank. (if the bearing surface is not scored)

either way, the car needs some diagnosing before any major teardown.

if you do have a bent rod, there is all the excuse you need to replace that Prothe TB kit.. its all gotta come apart again anyways to replace the rod. Franko6 here will ask you to send him both the #3 & #4 rods to match.

Best of luck, let me know if theres anythign else you might need.

Aaron
 
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