VW Vortex - Volkswagen Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
4,875 Posts
Discussion Starter · #1 ·
I also posted this in the MkIV forum...
I just took delivery of a new '02 TDI Jetta, and it seems like the steering wheel turns with a little heavier effort than my 1.8T Jetta and with more of the power steering pump 'hum'. Maybe I'm imagining this? On low speed U-turns is the only time I notice anything.
So my question - how much 'hum' is normal on tight low speed turns with VWs? It's not obnoxious, it's actually very quiet and I was thinking maybe it's just more noticeable on the TDI than the 1.8T.
Should I talk to the dealer? I don't think I would have noticed it, except my wife brought it up, and after driving both cars back to back, the TDI has a little more noise when cranking the wheel. Thanks.
 

·
Registered
Joined
·
123 Posts
Re: TDI power steering pump noiser than other VWs? (spongebob_squarepants)

I believe the pump is the same. If you are only hearing it on u-turns maybe it might be related to the CV joints on the suspension. The 5 speeds have true cv joints on both ends of the drive shafts while the automatics have cv joints at the steering hub end and tri-poids at the transmission side.
Since the tri-poids are not true CV's the rotational speed of the drive shaft on the output side changes up and down as it rotates. They are still common today because they are cheaper to build and simpler.
With tri-poids and other non cv joints like u-joints the greater the deflection angle the greater the rotational speed differences. This effect is cancelled by putting an identical tri-poind or u-joint on the steering hub side.
The down side of this is that cv joints can be used at much greater deflection angles than the other joints. This is why the VW T5 van can turn circles arounf the Chrysler minivans even though some of them have shorter wheel bases.
What I am leading up to is this...
VW uses tri-poids on the inner half of automatics to keep the cost down and cv's on the outer part to keep the turn radius the same as the 5 speeds. The rotational differences are absorbed by the torque converter at lower speeds and generally people don't use high steering angles at speeds where the converter locks up. The uneven loading will cause some additional noise in the drive line however.
Of course all of what I have mentioned here is pointless if the noise you are hearing is caused by the power steering pump stalling out because you have turned the steering wheel to its stops and the hydraulic fluid has no where to go. With the car stopped and engine running turn the steering wheel all the way in one direction. You will notice additional noises from the system if you hold the wheel against its stops compaired to letting go of the wheel after you have turned it as far as it will go. This might also be part of the noise you heard.
 

·
Registered
Joined
·
123 Posts
Re: TDI power steering pump noiser than other VWs? (spongebob_squarepants)

Oh yea.... I forgot to mention that the additional heavyness you feel in the steering might be caused by your steering wheel. If your 1.8t had the three spoke wheel and your TDI has the four spoke the difference is in the wheel. The three spoke is made of magnesium and weighs less that half of what the standard four spoke does. The extra mass does make a difference you can feel. I changed from the four spoke to the three for that reason and have never regretted spending the bucks to make the change.
 

·
Registered
Joined
·
4,875 Posts
Discussion Starter · #4 ·
Re: TDI power steering pump noiser than other VWs? (N5160U)

Yes, I have a 3-spoke on my 1.8T and 4-spoke on the TDI with the slightly heavier-feeling steering, so that makes sense. Maybe the 1.8T's tires are more turn-friendly as well.
The noise difference is so minor that I think it's just me being paranoid about my new VW. Likely the difference is the tri-poids you mention or the torque converter getting involved. I'm not turning the wheel to lock at any time.
Thanks for the info, more than I bargained for in fact.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top