Help Pls - strange noise coming from under bonnet

[dizmona]

I have a 2007 3.2l pajero, done just over 200,000km, for the past year or so I have had a strange noise coming from under the bonnet, sounds like a purging air noise or similar, does not affect drive quality, no limp mode, no loss of power etc. I had the inlet manifold and other areas of motor cleaned out a little while ago however this did not affect the noise. It is not turbo noise, I need some pointers if anyone has any, thanks Simon

[_jp_]

Under what conditions is the noise generated?

Any chance of you recording it on your phone and uploading it?

[dizmona]

JP, the frustrating thing is that it is not constant, it is intermittent and no consistency when it happens. I will certainly try to record it. cheers

[sharkcaver]

Check your intercooler hose hasn't parted ways with the intercooler. A reasonably common problem.

[dizmona]

Thanks Shark, will do.

[dizmona]

Gday Shark I have tried to upload file however the system is saying invalid file it is a m4a sound file from iphone, can I email you directly?

[dizmona]

Shark, the noise file has now been uploaded

[sharkcaver]

Dunno. Sounds like you have a chook in there.

[nstarrengower]

hi, i have the exact same noise, happens a few times when cold, on the first few brake applications, very rare to hear it after the first 10 minutes of driving, is it the ABS sensor ??, cheers, NSTARRENGOWER,,,,3.8l vrx ns 2007

[dizmona]

Interesting this noise happens also when I am not on the brakes so I am not sure that this is the problem, but I have no idea

[Axis]

Slightly different but similar to this noise - this was another forum members noise that was the same as I had for a long time. Mine was easily heard from inside the car. There are threads on the forum indicating it is the HBB motor (most issues on the Gen 3 section). I just had a new commutator put on my motor this week and put it all back together today.

I bled brakes today but will follow the process to bleed air from the HBB tomorrow as I have a vibration through the brake pedal when the HBB motor runs.

I am hoping that this is the end of the noise but it may take a few days to confirm as the noise was intermittent, but would occur once every 2 or 3 drives.

edit: our NS has done approx 294k kms.

Cheers,
James

[dizmona]

James my noise occurs even when i am not on the brakes, the noise is more prevalent when motor cold, when motor hot it makes likes an exasperated high pitch noise again sounds like an air purge or similar

[nj swb]

James my noise occurs even when i am not on the brakes, the noise is more prevalent when motor cold, when motor hot it makes likes an exasperated high pitch noise again sounds like an air purge or similar

The HBB is an "accumulator" that pumps up to pressure then stops. Over time the pressure can "bleed down" whether the brakes are used or not, so the HBB will run at seemingly random intervals.

Don't discount the HBB.

[dizmona]

just done some more research, might also be a faulty brake accumulator that is making the noise