Replaced snub mount...no improvement in vibration

[econnelle]

Owell....$14 spent and a few hours.

Replaced the mount...the bottom of the mount was in horrible shape...the rest of the mount of course was in perfect shape :)

Vibration still at idle, more so in R or D...now listening to the car run on the hoist I got a better idea of what might be happening.

How reliable is the idler system? AC compressor, Idler pulley, alternator, etc...this is an 02 3.0 which I think has a different accessory system than later models.

Vibration is mild at cold start. Starts once the motor settles down into normal idle. Put it in Drive/Reverse and its worse. Touch the gas and it goes away.

Warm engine its better but not always perfect. Now if I'm driving, put it in Neutral and come to a stop the idle is smooth. Put it back in gear and it vibrates. Put it back in neutral at a full stop and there is a minor noise/vibration.

So I'm thinking bearing somewhere in the accessory drive system. Any load at all and the bearings get upset. Thats why when I come to a stop in neutral, where the bearings were spinning at a high speed and coasted down without load everything is fine, apply the load, problem comes back and does not go away until I rev the engine and let it settle.

The front end need to come off to service that stuff?

[J-jizzle]

Idk about some of your Ideas, but a snub wouldn't help with vibration, and could make them worse if install was bad on a larger aftermarket one. Have to looked at your other motor mounts? Here is what the passenger side mount looked like after I took out.

Although It was NOT ripped all the way around when I pulled it out but it was 6/8 the way there. I went ahead a tore it the rest of the way and made it into a ash tray.

The other mount was not ripped but all the fluid was leaked out and in was smashed in on the top. This is a common for A4 owners

[shedpress]

were are the side engine mounts located on the 3.0? I have a vibration at speeds over 50 mph and wondering if it's one of those. The car has 72k miles on it. Thanks.

[diagnosticator]

Audi issued a TSB describing loose or cracked A/C compressor brackets causing vibration at idle speeds and noises. I will look for that TSB and forward it if you want.

[econnelle]

I had read about a few 1.8 owners that reported idle vibration and bad snubs...thought it was worth a shot for a few bucks.

I'll take the TSB, I looked on NHTSA's web site, found a few that might be close but they did not include specifics.

I'll check the motor mounts today...surprisingly the trans mounts and motor mounts look new.

I visually inspected them but I need to get a pry bar in there and see if they move.

I saw two located on the right/left side but where is the 3rd?

Is the 3rd active and I've been told?

Thanks for the info and suggestions...hopefully I'll narrow it down.

[J-jizzle]

I saw two located on the right/left side but where is the 3rd?

As far as I know there is just 2 main motor mounts(like in the pic above), a snub mount, and a trans mount.

[Dopefish]

I'd check your other two engine mounts as listed already but also take your spark plugs into consideration. When was the last time they were changed/serviced? Is the gap correct on all of them, are they the proper heat range and material for your mods or lack of mods if that is the case? What about their condition, any sign of lean (white, dry and eroded electrode), rich (black or moist electrode) or healthy (brown and dry) burn conditions?

Just something else to consider as I've had poorly gapped plugs or just old plugs that have greatly affected my low-RPM engine conditions, making it seem very rough.

[econnelle]

I'll check the plugs but this is pretty rough at idle but smooth as can be higher RPM.

Do these require those special $18 plugs that my 2.7t requires?

I never in my life would have spent $90 on 6 spark plugs but the guys at VAST swear by them and I was trying to fix a misfire issue at idle on my A6.

Car is dead stock...she did dealer service so I'll have to go through the paperwork but I'll pull a few and check them.

[dirtybrd]

A bad snub will not cause and idle vibration. Check the motor mounts and for the guy who said he has a vib@50MPH, look into having your tires balanced.

[Boosted3.0]

dirtybrd...my post was going to be identical to yours...thanks lol.

[econnelle]

Can't find a DIY for the engine mounts and my Bentley manual has not yet shown up.

Is it a big deal to pull them off for inspection?

[J-jizzle]

Can't find a DIY for the engine mounts and my Bentley manual has not yet shown up.

Is it a big deal to pull them off for inspection?

Not bad once you know the trick describe here in post number 3. It can be done with ramps and basic tools.
http://www.audizine.com/forum/showth...t=motor+mounts

You can also do a search "motor mounts" and might find some other useful stuff.

But all you basically have to do is un-attach some hoses that might get stretched in jacking up your motor and undo some bolts. I was kinda worried that I was going to fuck something up jacking my motor up so high. The passenger side mount was a bitch for me cause no matter how high I got the motor it wouldn't be enough to get the mount out. Finally I went balls to the wall and jacked the damn thing up as far as it could go (thinking that something was going to break) and got it out without damaging anything.

I think the main cause for the passenger side being difficult was that my leverage might have been off. Maybe you can get a better angle on the motor so it jacks up even.

I would not recommend doing this by yourself. You need a buddy to drink beer with and help you guide the bolts to there holes and spot you for other things. Also if you are using a floor jack you need to be very carful the board (on your oil pan) doesn't slip so much you can't let the motor down or up, you will know what I mean if you get stuck like this. Another suggestion is if you have to let the motor back down for any reason make sure the mounts are in there holes first or lined up. I almost bent the bolt on one of my new mounts doing this cause it came out of the top hole jacking the motor up to get the passenger side out.

If I had to do it again I would modify some wood that would hug around the oil pan (front to back) to keep it from slipping. Having the board slip made it hard to get the motor as high as it can go. Using a engine hoist should work too.

[diagnosticator]

Can't find a DIY for the engine mounts and my Bentley manual has not yet shown up.

Is it a big deal to pull them off for inspection?

I recommend using a 4X4 cut for length, to fit the span across the engine bay inside the fenders, the length is the same as the width of the hood. Then, using a length of 3/8" all tread rod, and nuts/fender washers, rig a suspension rod to support the engine from above. The lower end of the rod is attached to the front lifting point on the engine head. Arrange the 4X4 over the lifting eye on the engine, drill a verticle 1/2" hole in the 4X4, for the rod to pass through the 4X4, so that the rod is verticle over the lifting point eye fitting on the head. Place the fender washers on the rod, then the nut. Tightening the nut will lift the engine weight from the mounts, you can then raise or lower the engine as needed. With the weight of the engine supported by the 4X4, remove the upper mount nuts and lower brackets with the mounts. See pic.

[econnelle]

Thanks.

I have a hoist and a few tall telescoping jack stands so it should not be too bad...My neighbor has an engine hoist but I doubt I could get that in front of the hoist.

I tried your link but no luck...I also searched for engine/motor mount and wasn't able to find the same directions.

On the board trick, there are 2 pick up points for the engine, just use one?

That will give me enough clearance with the wood supported between the fenders, or over the fenders?

I went for a ride today with the engine/trans mount engineer at work. He said either mounts or idle tuning. He suggested checking the rear tranny mount first and wanted to see how the snub setup worked because there was a lot of fore/aft movement when I brake torqued in drive while he watched the engine motion.

Its $125 for the mounts....after considering the work involved I might order a set and skip the inspection...if its a couple of hours of work to get the mounts off I don't want to just inspect them, might as well replace them.

He gave me a few things to watch the mounts do while they are on the hoist and in gear, check that this weekend.

Thanks again for the help.

[J-jizzle]

Link fixed... BTW when you search you need to narrow down your search to titles only and in the B6 section if you have not done that already.

[diagnosticator]

Thanks.

I have a hoist and a few tall telescoping jack stands so it should not be too bad...My neighbor has an engine hoist but I doubt I could get that in front of the hoist.

I tried your link but no luck...I also searched for engine/motor mount and wasn't able to find the same directions.

On the board trick, there are 2 pick up points for the engine, just use one?

That will give me enough clearance with the wood supported between the fenders, or over the fenders?

I went for a ride today with the engine/trans mount engineer at work. He said either mounts or idle tuning. He suggested checking the rear tranny mount first and wanted to see how the snub setup worked because there was a lot of fore/aft movement when I brake torqued in drive while he watched the engine motion.

Its $125 for the mounts....after considering the work involved I might order a set and skip the inspection...if its a couple of hours of work to get the mounts off I don't want to just inspect them, might as well replace them.

He gave me a few things to watch the mounts do while they are on the hoist and in gear, check that this weekend.

Thanks again for the help.

The 4X4 should allow enough clearance, by removeing the mounts with the brackets, the engine doesn't need to be raised much, only enough to unload the mounts, and maybe a bit more for the upper mount stud, if it's a bolt, no additional lifting is needed. However, for additional lifting clearance, 4X4X6 blocks can be used at the ends of the span, and a longer 3/8 support rod, to raise the 4X4 support beam higher as needed. The use of the front engine lifting point only, requires that the transmission mounts are supporting the other end of the engine trans assembly. If the overhead support is used to suspend the engine alone, then the two lift points must be used together. For example, when removing the transmission but leaving the engine installed.

[econnelle]

Ok ran the car on the hoist this moring after changing the oil.

The mounts are fine...there is no fluid and no movement at all when going from park to drive, with the brake, without the brake, brake torquing it, its fine.

There is a bunch of fore aft movement but thats normal for these, correct?

I am almost sure its something in the accessory drive. I hear a racing/metal sound from the accessory drive when she shifted into drive/reverse. I inspected what I could but could not see the AC bracket if it had any damage to it.

So beyond taking the bumper off how much more is it to move the rad/condenser out of the way to inspect it head on?

I really wish my Bentley manual would hurry up and get here....

[diagnosticator]

Fore/Aft movement? Do you mean the engine/trans is shifting front<>Back along the long axis plane of the crankshaft/propeller shaft, as the trans is shifted D<>R? If it is, how much motion is there? It is not normal, and should not do that. I can't think of any lever arm that torque can act on to cause a thrust force acting to push/pull on the engine/trans like that.

[diagnosticator]

"I really wish my Bentley manual would hurry up and get here....".

In the mean time you can access the manual at http://www.ebahn.com $30 for 3 days.

[econnelle]

Sorry meant up/down movement, what the snub controls.

I am at the shop getting a balance so hopefully that adresses the high speed stuff.

[econnelle]

Ok got the tired done.

No improvement in a few things, improvement in other area's.

Accel from 50 to 60 still produces a pretty strong shudder but its there even at steady state in any gear just much more pronounced at WOT.

No shake and smooth driving upto 85mph where it gets what I'd consider severe, its pouring here so didn't do much above 90 but at 90 the frequency gets higher.

Its possible its still the accessory system just resonating at those speeds.

Car drives great otherwise.

However a new issue has popped up. Is there a friction modifier in the transfer case? I noticed this the other day that the transfer case takes a while to 'let go' in corners. Low speed corners followed by low speed acceleration give a slight shudder upto 25mph but I think thats just a factor of cornering speed and the time it takes to reach 25mph the transfer case has gone back to 2WD.

Feel it on WOT corners near 20-25 degree's of turn.

I used to set my differential based on how much friction modifier I used. More modifier the more it slipped. Just feels a bit tight.

Most people would never notice but I'm very sensitive to things like that.

I've never read of people having TC issues or changing fluid but might not hurt.

We're all car'd out today. Changed the oil in both cars, did the tires, changed the fuel filter...next weekend I'll prepare to take the whole front end off the car and run it to see what I can hear/see as far as a bad accessory part. I did video it but in the video its impossible to tell where the noise is coming from. The mounts never even moved. Them moving towards the outside can would indicate a problem but nothing.

OH and I forgot...I pull out of the garage after changing the oil in the A4 and waiting for the wife to get in the car. Car is running decent, not as smooth as it should at idle but awefully close. Turn on the headlights and the shudder gets worse.

Odd though that I turned on the blower fan on full, all 4 heated seats, everything to create a draw on the alternator and nothing made it change like the lights.

[Maverick]

maybe your CV joints/boots are fucked up