DanA100

There is a weird noise coming out of my engine compartment. It sounds like a noisy alternator or power steering pump. However the noise does NOT come from any of them.
It is from the back of the engine/front of the AT. I don't hear the noise all the time, only when I'm driving in the city and I open my window to hear it. When the car is hot, it goes away. Also, only sometimes, when I switch the gear selector a few times from "drive" to "reverse", "1", "2" and back it goes away for a while. I asked my Audi mechanic about it and if I understood right, he thinks that the noise is coming from the REAR crankshaft seal. He said that when the engine gets older, the seal becomes harder and noisy. He also said that it is harmless and will not have any bad consequences, except that I'll have to live with the noisy car. To fix it,(only if I want to) it will cost me more than couple of hundred $.
My question is, is this seal and noise really harmless for the engine/car? Has anyone else had the same problem? Should I attempt to fix the problem ASAP? Any other possible sources for this noise?
The engine in question is 2.3L, 5 cyl, 10v, non-turbo, with 146k miles, attached to rebuilt (25k miles ago) AT.
Thank you for your help!

Wrench

I'd check your transmission fluid level before anything else. I've not known rear engine seals to make noise when they age. You just get a nasty leak. Make sure you warm the trans to operating temperature before checking the trans dipstick. Also, be cautious of letting any rag lint or dust get into the trans. They are very sensitive to foreign matter. If you need a top off, do so in small increments. You do NOT want to overfill. Removing overfill is a pain, so take your time...

SteveAngry

if so then it's most likely the rear cam seal. Usually it will leak some oil too. Not anything to really worry about. The worst that will happen is that it will let in some unmetered air(i.e. vacum leak)

What worries me is the correlation of the noise to the tranny gear engagement. I would take Wrench's suggestion and make sure it's not the tranny making the noise. Check the fluid and confirm that it is not low...

Steve
Michigan

DanA100

I'm worried about the tranny too. I haven't driven the car today, but i will check the level tomorrow after i drive the car on the freeway.
My mechanic replaced the AT fluid 2-3 weeks ago so when i checked the level 10 days ago it was fine, almost touching the "max". I'll check it again tomorrow.
I had the noise before but i didn't hear it so often, only when the car was getting cold at night, and driven slow.
Now, i hear it more and more often when i drive around the city. I always thougth that it is comming from the Power Steering pump or even the alternator. You know how these things get noisy some times before they break. I suspected my belts too. I even found a good used PS pump.
Then i realized, a week ago, that the noise is comming from the back of the engine and all my worries started. I really don't want to rebuilt my tranny only 25k miles after the last rebuilt.
ALSO, my mechanic did something else...i guess this is important and i didn't mentioned it the first time. When i took the car there the noise was there. We could hear it and etc. The car was running and he opened the oil fill cap just for a second and closed it back. The car almost stalled which is normal, but after the "open-close" of the cap the noise went away! Can you explain this?

Wrench

Tell me, what year is your car? Has the motor been replaced? Is it a quattro?
Wrench

DanA100

Car is 1989, non-quattro, AT.
I'm almost sure that the motor has never been replaced. i've had the car for the last 80k miles. Cureently it has a little less than 150k miles on it and runs great. Just that noise that i started to hear the last couple of months.

Wrench

I'm going to stick with my trans fluid level scenario. Have you had the chance to check it?

DanA100

I did check it and it was actually above the top dot. In other words, it seems to be a little overfilled. I guess when they did the tranny servive few weeks ago, they overfilled it again. (happens for the second time - the first time fluid was comming out of the filling pipe and vent openings at high speeds)
Can all this be related to the noise i've been hearing?

jimweisptd

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My 85 5000T has made exactly the same sound for the 11 years I have owned it. The tell-tail sign it is the seal is, when it is idling pull the dipstick out, the sound will stop as the vacuum is pulled through the tube not the seal. I can't beleve the sound hasn't changed in all the time I have had the car. The only problem I have related to the seal is failure to start sometimes when warm engine has been started after 1-2 hrs.

DanA100

I'm almost sure now that we both have the same problem. If you read one of my posts, i said that when the oil fill cap is open just for a second as the car is idling, the sound goes away. You are saying that the same thing happens with you when you pull the dipstick. Sounds the same to me.
It's a good news that 11 years and your car is still running fine. Any oil leaks? How hard was to start the car when it failed to start one of these times you mentioned? Did it require just only few more tries or you were stuck for a long time? I mean, how serious was that starting problem?
BTW, Your car really looks great.