[Dhandley01]

Hello, I have this strange issue with my Touareg that I've been battling since I've owned it.

When the A/C compressor is on, there is an excessive vibration that can be felt at any RPM and wheel speed. The vibration remains the same and is quite frustrating on longer road trips because it can even be felt at highway speeds. I popped an A/C gauge on the low pressure port and do not see that it is overcharged. The HVAC system functions as it should.

Occasionally, the vibration will occur even with the A/C compressor turned off. This is quite rare though. One last note... when I shut the car off, the vibration continues for a good 3-5 seconds after the engine has stopped spinning.

If anyone has an idea what this could be, I would love to hear it!

Thanks!

 

[TRespect]

Do you have a vcds cable. If so what does the scan say?
Did you own this Treg from new or bought used?


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[Dhandley01]

Do you have a vcds cable. If so what does the scan say?
Did you own this Treg from new or bought used?


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I do not have a cable, but I do not have any hard codes throwing any lights. I bought it used about a year ago and it has done this vibration since.

 

[TRespect]

I think a vcds cable would be a good investment if you’re keeping it.
Now things you need to check:

Is the vibration felt inside the car and outside the car? If inside only it might be the blower motor but that’s far fetched. I don’t know how bad is the vibration.
If you can see or feel the engine shaking in the engine bay it might be either a bad compressor or bad engine mounts.
Is the vibration present at idle (stopped) with ac on? What happens when you rev the engine?
Try pushing at the vibrating engine somehow and see if you are able to stop it. Don’t go putting your hands in the engine bay without taking the necessary precaution. If you can stop the vibration it might mean engine mounts. I know it seems weird to be pushing against the v6 to calm it but you need a way of testing your engine mounts.
A vcds scan will probably give additional clues to your issue. It does not have to be a hard code to cause trouble. You need to know how your Treg is feeling on the inside unless you want to go to a healer who will make it eat the whole valley of herbs and new parts before finding out it’s a short to ground or loose wire is which driving it crazy


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[Dhandley01]

I think a vcds cable would be a good investment if you’re keeping it.
Now things you need to check:

Is the vibration felt inside the car and outside the car? If inside only it might be the blower motor but that’s far fetched. I don’t know how bad is the vibration.
If you can see or feel the engine shaking in the engine bay it might be either a bad compressor or bad engine mounts.
Is the vibration present at idle (stopped) with ac on? What happens when you rev the engine?
Try pushing at the vibrating engine somehow and see if you are able to stop it. Don’t go putting your hands in the engine bay without taking the necessary precaution. If you can stop the vibration it might mean engine mounts. I know it seems weird to be pushing against the v6 to calm it but you need a way of testing your engine mounts.
A vcds scan will probably give additional clues to your issue. It does not have to be a hard code to cause trouble. You need to know how your Treg is feeling on the inside unless you want to go to a healer who will make it eat the whole valley of herbs and new parts before finding out it’s a short to ground or loose wire is which driving it crazy


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Thank you for the suggestions! I will have to test some of those and report back. Also, not sure why I haven't picked up a VCDS cable yet... this is my 11th or 12th VW/Audi lol. I guess having friends with VCDS could be a contributing factor!

One thing for sure is that the vibration can be felt and literally heard from inside and outside the vehicle. It can be felt at idle sitting in park, in drive at idle, and while driving. The intensity or NVH is basically the same at any engine speed and wheel speed. The vibration is intense enough to cause some interior rattles. I am sort of perplexed... I initially assumed it was engine mounts, but I would imagine that the frequency of the vibration would change throughout the RPM range.. it does not. The engine definitely has a little movement, but nothing in excess of what i'd expect for a diesel while running. The engine does appear to vibrate a bit more (visually) when the A/C is turned on. It really is a bizarre scenario and I'd hate to throw parts at it for something that is really just an inconvenience more than anything.

 

[TommiT]

It's the fact that the vibration continues for several seconds after the engine has been turned off that I find puzzling.

Is an out of balance fan (missing a blade perhaps?) still running?

 

[Dhandley01]

It's the fact that the vibration continues for several seconds after the engine has been turned off that I find puzzling.

Is an out of balance fan (missing a blade perhaps?) still running?

Well. You solved the mystery! The big upper rad fan that kicks on with the AC is the culprit. There aren't any missing blades, but there a quarter sized chunks missing out of 3-4 blades. The vibration is definitely coming from there and it gets worse the faster the fan spins.

Now where to find a replacement and hopefully it wont involve draining the coolant and putting into service position.

 

[TRespect]

That’s some happy ending


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[TommiT]

It's very satisfying when a random thought turns out to be a good one especially sight unseen and three thousand miles or so distant!

Here are more random thoughts.

Go to your local tire company and beg/buy a couple of stick on wheel weights.

How much weight you would need to add to each broken blade to bring the fan into balance is hard to say but the weights are easily cut.

You might only need to add a bit of weight to the middle one of the broken blades to balance the fan.

I would use rubberized self-amalgamating tape wound round the blade to secure the weight(s) before starting the engine to avoid the possibility of shrapnel!

Alternatively, the fan is fubarred anyway so would cutting matching chunks off the blades opposite bring it back into balance?

I would get a new fan on a return basis in your possession first should you think of trying these shady tree fixes!

Let us know how you get on.

 

[Dhandley01]

It's very satisfying when a random thought turns out to be a good one especially sight unseen and three thousand miles or so distant!

Here are more random thoughts.

Go to your local tire company and beg/buy a couple of stick on wheel weights.

How much weight you would need to add to each broken blade to bring the fan into balance is hard to say but the weights are easily cut.

You might only need to add a bit of weight to the middle one of the broken blades to balance the fan.

I would use rubberized self-amalgamating tape wound round the blade to secure the weight(s) before starting the engine to avoid the possibility of shrapnel!

Alternatively, the fan is fubarred anyway so would cutting matching chunks off the blades opposite bring it back into balance?

I would get a new fan on a return basis in your possession first should you think of trying these shady tree fixes!

Let us know how you get on.

All very good suggestions! I managed to find a listing on eBay for just the fan blades. I'm just going to wait it out and replace it when it shows up sometime next week. The fan has lasted this long! haha