Finally found the problem !!!

[wayneair]

Sorry to resurrect a super old thread, but my car has exact same issue, with rather large vacuum leak. If I JB-Weld it, will that make it a huge PITA if I have to eventually replace the pump? Seems like it would be pretty difficult to separate the hose from the pump.

if you still want/need to replace the pump, there are 3 bolts that hold it to the back of the head. the JB Weld does not interfere with the mounting bolts. the JB Weld is only applied where the nipple is mounted/inserted to the pump body. the hose will still be free to remove.

the other option is the disengage the nipple from the pump housing body and replace the worn o-ring.

either way will accomplish the same objective, to stop the God-awful racket that comes from a small vacuum leak.

[a1dan_87]

Have a similar issue here. I checked the hose you've replaced, that didn't seem to be it. I'd almost say it sounds like a knocking/banging down low, that you can only hear inside the car?

Sent from my ZTE B2017G using Audizine mobile app

[a1dan_87]

Hi Guys,
For a month now, we get cold fronts in FL and since, when starting the car in the morning, I was hearing a really bad metallic banging noise, almost like a bad valve but once the car was warm, the noise would disappear. Checked the oil, WagCom for codes but everything was fine.
This morning, I replaced my cam follower, like every 15 000 Miles (and still, everything is fine at 100 000 miles). Then, started the car to check for leaks and I finally found where the stupid noise is coming from:
First picture to locate the area of concern:
Vacuum pump behind the High Pressure Fuel Pump. Notice the black traces in the area



Now some close up:
Check the difference between the 2 pictures and notice the gap when the elbow is pulled. When cold, the hose is really rigid and since the engine shakes a bit, it triggers the banging noise. Once warm, the hose absorbs the vibrations and the noise is gone. Of course, there is a leak as well.
Went to the dealer to see on ETKA what spares were available and the Vacuum pump housing needs to be replaced. No, thank you. Grabbed some JB Weld on my way home and tomorrow, will pull off the elbow and will apply a nice bead around the metallic tube of the vacuum housing




Let me know if any question

Phil



Phil

Reviving an old thread! Anyways, after doing the tests and following what you described, that didn't work for us to determine it was bad. The noise also remained when the car was still warm.

However, we had the car in for some matinence and VC replacement, and the shop noted the noise, and its source as the brake booster vacuum pump. They replaced it and the car runs smooth as butter!

Sent from my ZTE B2017G using Audizine mobile app

[Hupa]

Advice on how to depress the nipple tab next to the valve cover? The gap is very narrow for any tool. Then what is the size of the O-ring? Thanks!

[Jayz691]

Advice on how to depress the nipple tab next to the valve cover? The gap is very narrow for any tool. Then what is the size of the O-ring? Thanks!

I did mine with the pump off, good to pull it and change all the seals. Maybe a small pic tool.?
O-ring is 18x2mm iirc.

Sent from my CPH2611 using Audizine Forum mobile app

[Hupa]

Yes, it’s clear how it comes off ehen the pump is on the table but I was wondering if it (o-ring change) could be done without removing the pump. :)

[Theiceman]

theoretically possible of course but good luck compressing the opposite tab behind the engine.. and you need a third hand to pull out the nipple once compressed... just undo the thee bolts and get on with it,