Car sounds like vacuum cleaner on start

[philthy]

Hi folks.

My car has taken to sounding like a vacuum cleaner for about a minute when I start it from cold. Any idea what this might be? I popped the bonnet this morning to try and listen to where it was from but couldn't really pinpoint it. It sounds like a motor/ fan spinning at high RPM which winds down after about a minute. Also, the idle appeared to drop (to normal speed from slightly high) when it stopped.

Cheers,

-Phil,

[noone]

Its not just the choke? My car sounds rough, idles around 1000 rpm for 30 sec - 1min before settling down.

The combustion is much richer, which helps protect the engine from damage when cold.

[philthy]

hmm, not sure. It's a distinct fan/ motor kind of sound, and fairly loud. High pitched though, not like the cooling fan.

[mattyf]

hmm, not sure. It's a distinct fan/ motor kind of sound, and fairly loud. High pitched though, not like the cooling fan.

sounds like an auxiliary air pump problem.

[philthy]

sounds like an auxiliary air pump problem.

Hmmm. What does that do?

Maybe I have a split pipe or something.

[mattyf]

Hmmm. What does that do?

Maybe I have a split pipe or something.

something to do with making cleaner exhaust emissions on startup.
the bearings in the electric motor could be u/s.
you could check for leaks by feeling the small hose that runs from the airbox to the auxiliary air pump when its running

[philthy]

something to do with making cleaner exhaust emissions on startup.
the bearings in the electric motor could be u/s.
you could check for leaks by feeling the small hose that runs from the airbox to the auxiliary air pump when its running

Will have a look at the hose. I googled auxilliary air pump and what came up did look familiar. I think it hangs off a bracket on the front of the motor and that was where the noise was coming from.


Thanks mate.

[Joe Chu]

Will have a look at the hose. I googled auxilliary air pump and what came up did look familiar. I think it hangs off a bracket on the front of the motor and that was where the noise was coming from.


Thanks mate.

Air pump pumps air into exhaust on cold start up to heat the catylyst up for cleaner emissions and get the cat up to temp quicker. The pump filter might be dislodge causing the noise?

[philthy]

Air pump pumps air into exhaust on cold start up to heat the catylyst up for cleaner emissions and get the cat up to temp quicker. The pump filter might be dislodge causing the noise?

Hi Joe. Where is the pump filter located? I felt the pipes coming from the pump yesterday and had another listen. Couldn't feel any leaks and the noise definately seems to be coming from the pump.

Will take it to the mechanic when I get a chance.

[Petrina Polo]

Does the noice stop after 30 seconds or so... if so its normal. forget about it..

Pull the hose off the airbox, start the car cold and you will feel the vaccumm, after 30 seconds stops.

Maybe you hose has come lose somewhere for the additional noise..

I thought the same thing, went to VW about it and they said forget about it, normal