1997 1.9TDI power loss & noise?

[Possu]

Couple of days ago my TDI started making a noise a bit like air being sucked in? It comes from the front right hand side and starts at 1,700rpm through to 2,200rpm and is very noitceable with the drivers window down. There's a corresponding loss of power at the same time. Past 2,200rpm the noise pretty much disappears but comes back nearer 3,000rpm along with a dip in power.

Apart from that, the car's fine, returns an average of 55+mpg pretty much anywhere with 65mpg bimbling along.

I've checked the air filter, a bit dirty - I was hoping that a clogged air filter would have explained the power loss but wouldn't have explained the noise. I then thought the turbo may be on it's way out but am now thinking that a (vacuum?) pipe of some sort under the bonnet has either worked loose or has split, hence the sucking air noise - any ideas?

The car's on 116,000 miles with a FSH, I bought it used in early 2007 at 87,000 miles. Checking my records, I can see that the air filter was last changed in February 2008 at 93,00 miles - should it have been changed more frequently?

All thoughts appreciated. :1zhelp:

[passat 130 tdi]

front right hand side is where the intercooler pipes are , you need to take the underbelly trays off and have a poke about.

[Possu]

Thanks, will have a look at the weekend.

Are they prone to splitting or working loose?

[Possu]

Not sure my TDI has an intercooler?

The air inlet is at the top of the grille, near the bonnet catch, the snorkel goes straight in to the airbox.

[passat 130 tdi]

Not sure my TDI has an intercooler?

The air inlet is at the top of the grille, near the bonnet catch, the snorkel goes straight in to the airbox.

oh ok then , maybe someone else can help.

[creedxup]

Not sure my TDI has an intercooler?

The air inlet is at the top of the grille, near the bonnet catch, the snorkel goes straight in to the airbox.

Your Turbo'd Passat has an intercooler, the air routes from the airbox to the turbo, down to a crosstube, across the front of the car to the intercooler and then to the intake manifold.

Where the flexible pipe joins the metal crosstube is where the pipe normally spliits or becomes disconnected.

Remove the undertray and follow the pipe from the turbo and you'll be able to check all the connections.

[Possu]

Your Turbo'd Passat has an intercooler, the air routes from the airbox to the turbo, down to a crosstube, across the front of the car to the intercooler and then to the intake manifold.

Where the flexible pipe joins the metal crosstube is where the pipe normally spliits or becomes disconnected.

Remove the undertray and follow the pipe from the turbo and you'll be able to check all the connections.

Thanks, I thought about this & assumed that the intercooler would be located before the air filter but have since confirmed what you said i.e. the intercooler is located out of sight & that filtered air passes through the intercooler.

[Possu]

oh ok then , maybe someone else can help.

No, you were right in the first place. :D

[DSG4ME]

Check all the pipes that lead to the air filter housing, there's one vac pipe that if not on or split stops the turbo working, and the air filter is 40k, but I think that's too long and change them every 20k. hth.

[martin1810]

Have a look here. http://sites.google.com/site/1810martin/vw-passat-b5-tdi-turbo-control

[passat 130 tdi]

No, you were right in the first place. :D



:biglaugh:

[scotty33]

Very helpful Link Martin 1810, but is this car a 90hp or 110hp Possu? 90hp is not VNT turbo and the wastegate control is very different...

[martin1810]

Yes, just looked at year 1997. It's a non PD. The turbo is different but the use of vacuum lines and N75 valve is similar. So problem could still be a damaged intercooler, intercooler pipe or a vacuum hose as put forward by the previous poster. I really must get new glasses.