loud idle tapping sound

raikky

Veteran Member
Joined
Aug 20, 2010
Location
England, Sheffield
TDI
vw polo 1.4 tdi se pd
when the engine is in idle, there is a loud tapping sound. but it goes as soon as a rev , but at idle, it sounds horrible. its like the gear is touching some part of the engine which is turning. i think this because if i hold the gear stick, and push it to the right, it goes, and you just hear normal engine sound. but without doing this, there is a loud tapping sound. whether ive got the gear stick in neutral 1st second 3rd etc, if i push to the right, the tapping sound goes. :s any thoughts?
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Moving the stick to the side does not engage gears so I don't think it's a transmission problem. Go look at the linkage for something loose.
 

CDrake

New member
Joined
Jun 4, 2008
Location
Kalamazoo, MI
TDI
2001 Jetta GLS
I think I may have the same problem. It started rather suddenly just a few days ago. Mine is a 2001 Jetta, auto trans (rebuilt in spring '09), 160,000 Miles. Runs the same as always at speed until I get to a stop light and then it sounds like a giant jar of bolts being shaken in a tin can. I know Raikky described it as a tapping or like a gear was touching. While I wouldn't have described it that way, I think we might be experiencing the same thing.
When it first started for me I was near my mechanic (Flying Dog Garage in Parchment, MI) so I took it in. I didn't even have to go inside because when I came to a stop the noise was so loud that my mechanic came outside to see what was wrong!
So far he's checked the cam and engine mounts and is working on troubleshooting fuel supply and then injector pump. No CEL, RPM at idle are consistent with pre-noise RPM. Happens at idle in drive, neutral, or reverse. I'll be sure to update if I find out what's going on!
 
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raikky

Veteran Member
Joined
Aug 20, 2010
Location
England, Sheffield
TDI
vw polo 1.4 tdi se pd
cdrake if you fix it let me know what it was! maybe we have the same problem.

i describe it as a tapping sound because if you were to be able to tap your index knuckle on your wooden desk 800 times a minute loudly, thats what it is like (or try as fast as you can)

usualy, it will go and be a little bit quieter after about 45 mins. but there is no pattern, i drove for 4 hours once and it still was tapping whenever the engine is at idle. other than that, the car runs fine. and the tappin has not got worse, but it sounds worrying.

ill record the sound on my phone and post it, if it picks up the sound.
 

CDrake

New member
Joined
Jun 4, 2008
Location
Kalamazoo, MI
TDI
2001 Jetta GLS
I got a call from my mechanic today saying that the bolts on my torque converter were loose and causing this rattle type noise. I had the transmission reman'd a year and a half ago and we think they didn't tighten to spec or something. Either way, now that everything's tightened up the noise is gone. This was VERY welcome news as we thought the culprit may have been the injection pump.

raikky, I'm sorry to say I don't think this helps your problem much. I hope you find it and that it doesn't cost you much to fix.
 

vwgtiman

New member
Joined
Mar 13, 2008
Location
PA
TDI
05 Jetta GLS
Belt Tensioner

I have the same loud mech. clicking noise. I traced it to the fact that serp belt is stretched and the idler pully (tensioner) is extended out almost to the stop... so when ideling the tensioner will actually hit the stop and make a noise. Fix: New belt. Also, I replaced my alternator a while back with an ebay special and it had no clutch. This may be why my Autozone belt stretched or it may not be....
 

raikky

Veteran Member
Joined
Aug 20, 2010
Location
England, Sheffield
TDI
vw polo 1.4 tdi se pd
ok so today i was driving past a garage and thought ok lets see if they know what it is. i took it in, sat down in waiting area. they heard the sound, had the car on the ramps and within 2 mins he came to me and said 'come though please' and showed me what was causing this sound. i cant remember what it was but it look like 2 very thick cables or something and they were just tapping something or each other i cant remember. ill ask himn next time i see him when he does me LCAs. didnt even charge me awersome. my kinda mechanic. he said it can be quite common and is nothing to worry about it just sounds nasty but sint.
 
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