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Discussion Starter #1 (Edited)
Hello all,

98, 1.8t, SW, Stock, 262.200 miles.

Excessive engine vibration is the single most annoying problem I have had with this car. It is affecting the comfortable driveability of the car. Especially on highway. One thing for sure is I AM PRETTY SURE THE VIBRATION IS ENGINE RELATED. It shakes bad when idling and on highway. Let me explain what I have done so far to address the issue although failed to solve it.

-I replaced the motor and transmission mounts with Febi brand. I aligned both the MMs and the snub mount according to guidance offered in this forum. So much that I realigned the MMs many times and again, it did not work and I drove almost 100 miles and I tightened the MMs. The snub mount is not touching the frame either. Vibration persists.

-I replaced the CV axles with Raxles. Looks fine so far. the steering column is not shaky. I feel the vibration especially through the gas pedal.

-Replaced the entire front and rear suspension with Sachs and the control arms with a kit from FCP.

-Replaced the spark plugs with NGKs with 0.32 gap.

-Cleaned the PCV lines and replaced the cracked breather tube.

-Replaced the manifold gaskets.

-Cleaned the throttle body. Aligned with VAG-COM.

-The only thing left to be replaced is the CCT. I have the part and due for replacement. (It has the typical "diesel engine" sound. Would it be the culprit?)

-No check engine.


I really appreciate any suggestions you offer that will stop the engine vibration/shaking. I am even ready to give a gift card to he who helps me solve the issue. I love my car and want to drive comfortably.
Thanks.
 

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The ICM 'should' throw a code if it's failing . That said it does sound like a misfire . Were NGKs original equipment ? If not try going back to the original spec Bosch plugs - these engines are super fussy about plugs .
 

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Discussion Starter #3
I havent had CEL for more than a year. I vag-commed and there is no misfire. Actually all the parameters look normal. Yes, NGSs are original. I changed them last week.
Oh by the way, I have unplugged the MAF and driven like that. No avail!
 

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I havent had CEL for more than a year. I vag-commed and there is no misfire.
By that, do you mean you watched the misfire counters while the engine idled and shook and saw no excessive misfires being registered?

Two things could cause this.

Something causing the engine to misfire or not run with equal output from all cylinders. Usually the misfire counters would pick this up or you'd get trouble codes.

Something physically out of balance causing vibration when it's spinning.
 

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Auto or manual? Autos have a tendency to vibrate a little more at idle while in drive.

Have you ever replaced the viscous fan coupling on the car? There is one fan (driver's side) that is belt driven in addition to the electric cooling fan (passenger side). If the coupling locks up, I've read it causes massive vibrations as the bearing starts to get more play in it. That could easily cause vibrations at any engine condition. I wish I were home (will be in a week's time), I'd forward along a used coupling I've got in my garage to help you out for the price of shipping. It wasn't bad, just found a newer one at the junkyard. Aside from a misfire, this is one of the only things I can think about that would cause engine vibrations, aside from it being some other accessory or internal engine part (not sure what internally would cause that.)

One way you can test it is by turning on the motor, open the hood, take your hand and a rag, and CAREFULLY, try to stop the fan from rotating. It shouldn't give you a lot of resistance to do so, and you should be able to hold on to it and keep it still while the motor runs. That's a simple test, it could lock up later when the motor is at temp. Usually you can hear the loud WHIRRRR of the fan after taking off from idling at a light on a hot day, and it goes away. If it's constantly loud, then I'd start looking into it.
 

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What do you mean "idling on highway " ?. This is imposible ,the strong shaking without CEL comes on.
I suggest the motor mounts are related to the shaking.
 

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since you said on facebook you got metal flakes out of the oil,i would pull the valve cover and check if your both cct pads are still atached to the cct?
 

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Discussion Starter #10
Steve,
I did watch the idling misfiring parameters on VAG. All of them were zero. In order to test if the vag com is properly communicating with the car, I unplugged one of the ignition coils and that piston gave misfire counts. So, there is no misfires. You may be very right. I am inclining there is something out of alignment that is causing the vibration.

Here is one more thing; one of the most suspected suspect! is the CCT. But, when I cold start the engine in the morning, the CCT makes no noise for about 15-20 second. The engine runs very silently. But, the same annoying vibration is there even withing the first 15-20 seconds. So, would this mean I can eliminate CCT as the culprit?
 

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Discussion Starter #12
Bora,

It is automatic. I am aware that automatics are prone to vibration more so than the manuals. But, this vibration is such that it causes the sunroof make noise!

I will change the viscous fan as well. To be sure; it does not necessarily mean that the coupling fan is OK even though the fan does its job of cooling the system properly, right? Is this what you mean? Because, the fan adjusts itself to turn faster when the engine needs cooling. And, I can hear the air blowing sound when it is engaged. Does this mean it works normally?
Auto or manual? Autos have a tendency to vibrate a little more at idle while in drive.

Have you ever replaced the viscous fan coupling on the car? There is one fan (driver's side) that is belt driven in addition to the electric cooling fan (passenger side). If the coupling locks up, I've read it causes massive vibrations as the bearing starts to get more play in it. That could easily cause vibrations at any engine condition. I wish I were home (will be in a week's time), I'd forward along a used coupling I've got in my garage to help you out for the price of shipping. It wasn't bad, just found a newer one at the junkyard. Aside from a misfire, this is one of the only things I can think about that would cause engine vibrations, aside from it being some other accessory or internal engine part (not sure what internally would cause that.)

One way you can test it is by turning on the motor, open the hood, take your hand and a rag, and CAREFULLY, try to stop the fan from rotating. It shouldn't give you a lot of resistance to do so, and you should be able to hold on to it and keep it still while the motor runs. That's a simple test, it could lock up later when the motor is at temp. Usually you can hear the loud WHIRRRR of the fan after taking off from idling at a light on a hot day, and it goes away. If it's constantly loud, then I'd start looking into it.
 

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Discussion Starter #13
since you said on facebook you got metal flakes out of the oil,i would pull the valve cover and check if your both cct pads are still atached to the cct?
I will do so. But as I said earlier when I cold start the engine in the morning, the CCT makes no noise for about 15-20 second. The engine runs very silently. But, the same annoying vibration is there even withing the first 15-20 seconds. So, would this mean I can eliminate CCT as the culprit?

Here is the engine:

 

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Unless the video just makes it sound worse than it actually is, that sounds horrible!

Sent from AutoGuide.com Free App
 

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The loud CCT after the engine is warm (and louder if the engine is really hot) might be a bad CCT or might be low oil pressure. The CCT needs oil pressure to "pump up" and apply tension to the chain. Do you have an oil pressure gauge on the car? If not, it wouldn't be a bad thing to have. What weight oil are you running?

Seeing as your rough idle happens independent of the CCT noise, they could be unrelated.
 

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loosten the snub mount while the car is on the ground run it for a while untill there is no vibration then slowly tighten each bot in a triangular pattern (top right, middle left, bottom right) dont torque them all down right away just little titten of each untill they are all torqued.
 

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Discussion Starter #18
5W-40 Pennzoil Euro Synt. I am begining to belive the vibration is not related to CCT. But still I will replace it. Any suggestion for the oil pressure gauge?
The loud CCT after the engine is warm (and louder if the engine is really hot) might be a bad CCT or might be low oil pressure. The CCT needs oil pressure to "pump up" and apply tension to the chain. Do you have an oil pressure gauge on the car? If not, it wouldn't be a bad thing to have. What weight oil are you running?

Seeing as your rough idle happens independent of the CCT noise, they could be unrelated.
 

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Discussion Starter #19
loosten the snub mount while the car is on the ground run it for a while untill there is no vibration then slowly tighten each bot in a triangular pattern (top right, middle left, bottom right) dont torque them all down right away just little titten of each untill they are all torqued.
Is it possible to loosed the snub mount? I thought it is connected to the engine bay.
 

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Is it possible to loosed the snub mount? I thought it is connected to the engine bay.
You are somewhat correct in your statement of the snub mount being permanently affixed. The snub mount is stationary on the "cross tube" AKA metal intercooler pipe running underneath the radiator. The amount of support provided to the front of the engine can be adjusted by repositioning the "stop" it fits into by loosening/tightening the screws which hold the stop in place.

Your CCT sounds louder than my TDI! I'm with Steve and the others, check your oil pressure for sure. Have you ever had starter problems possibly leading to an out of balance ring gear?

Has anyone ever heard of or experience a vibration damper/harmonic balancer going bad on these engines before?
 
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