Noise for the first 30 seconds daily

passat
volkswagen

#1

I have a 2005 VW Passat (6 cylinder) that has a unique noise as follows: It sounds like a metal deck of cards shuffling or a rotor. It happens 100% of the time on my 1st start of the day (car is in a garage in Los Angeles)for only 30-45 seconds and ONLY when the car is in Drive or Reverse. The noise stops when I put the car in Neutral or Park. After that amount of time it subsides and will not be heard again until the next morning. I have noticed that if the car is out late into the evening, it will not make the sound the next day. CAN YOU HELP ME? Mechanics have thought about catalytic converters and air pumps. But they have not solved the problem.


#2

I would just be looking for a loose heat shield or loose shield or shroud of some kind. I’d speculate that the only first thing in the morning part has to do with how cold the engine is - it runs differently and thus its vibrations are different when first started up.

Of course, that is a shot in the dark but looking for simple things first is always best.

Perhaps you just need to arrange to leave it with a mechanic overnight (so long as they don’t take it out cruising the town late into the night).


#3

I mentioned heat shield to a mechanic before, I will do so again. And, yes, I actually have to leave it at the shop for 2 nights, 1 to hear the noise and diagnose it, and one more to see if the repair worked.

Thank you very much. I am on it!!


#4

Also, does that explain the drive or reverse, not neutral or park?


#5

It might. Its all about the frequency of the vibrations - which are different when the car is in gear. Basically a cold car engine is likely to vibrate more in gear than out.


#6

Thank you again. G’night.


#7

Tracy, Have The Engine Mounts, Transmission Mounts And Engine Anti-Roll Device Been Checked ?

Your engine “rolls” or moves slightly when put under “load”. Neutral or Park relieve this “load”. Perhaps the engine is moving too much because of worn mounts / anti roll device. The mounts themselves could make noise or cause something to vibrate or contact another part of the car.

I can’t explain the 30-45 second duration except that as the cold transmission fluid heats up or parts expand, etcetera, the engine movement or proximity of some parts may be altered slightly.

Anyhow, I’d have that checked. Stranger things have happened.

The catalyst honey comb structure inside the catalytic converter can break up or break loose and rattle.

I’d go to the back of the car when it’s cold and gently kick the tailpipe back and forth quickly and try and set it vibrating. Sometimes you can recreate the rattle and pinpoint it to the exhaust system.
CSA


#8

Thank you very much. Does anyone feel as if it might be a transmission problem since it’s connected to be “in gear?”


#9

Does anyone feel as if it might be a transmission problem since it’s connected to be “in gear?”

All things are possible, but that one is very unlikely in my opinion.

However, as I recall changing transmission fluid is no easy in that car, but I would suggest that now would be a good time to change it. Not that it is likely to fix anything, but as a preventive of future wear.