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View Full Version : Valve Cover Gasket...(Also Suction Pump)



audiFUEGO
12-05-2007, 08:32 PM
Im changing the VC gasket tommorow because im pretty sure its leaking oil..

but my question is it possible that its leaking air also?

AudiA4_20T
12-05-2007, 08:51 PM
lol why do you say that?

audiFUEGO
12-05-2007, 08:53 PM
because my vac is 19-20 and idle and only 21-22 when in gear... i want to know if a boost/vac leak could possibly come from that gasket.

salz2135
12-05-2007, 09:31 PM
there shouldn't be "boost" in that part of your motor : )

audiFUEGO
12-05-2007, 09:55 PM
ok...so no vacuum either im guessing?

Could the head gasket be leakin air?

I'm trying to figure out how i could have such a big boost leak (-17% PT) and no vac leak (-0.5% idle)

Rosati
12-05-2007, 10:05 PM
you have an 01 , it could be plenty of things, But im sure its neither of those two...

audiFUEGO
12-05-2007, 10:11 PM
you have an 01 , it could be plenty of things, But im sure its neither of those two...

Ive spent over 50 hours replacing every hose that could be leaky, vac valves, pcv valve and supporting hoses, IM gasket... all the vac lines have been changed and clamped...

and it seems like everytime i seal one leak, it runs good for a few days and then another leak opens up. The more i fix, the more the weak spots give out.

Rosati
12-05-2007, 10:18 PM
How about the "Z" hose from the block to the pcv system mentioned in my Head removal writeup?

Cant hurt to try that.

audiFUEGO
12-05-2007, 10:19 PM
The one with the plastic end? Replaced. The old one crumbled when i tried removing it.

audiFUEGO
12-05-2007, 10:28 PM
Is there any way, when pressure testing, to test after the throttle body?

salz2135
12-05-2007, 11:10 PM
seems like that would just be a compression test.

GetBoosted84
12-06-2007, 04:11 AM
seems like that would just be a compression test.

A compression test would check to make sure the head gasket, rings, etc. are not leaking. The valve cover gasket and head are above the spark plugs and where the compression tester would test.

audiFUEGO
12-06-2007, 02:55 PM
No not a compression test... i need to pressure test to look for leaks. But will a pressure test go beyond the throttle body? I need to test all the little hoses.

Today i had a feeling that my leak was coming from the purge valve assembly. Everytime i would wiggle that assembly it seemed like the engine would buck a bit. So i grab some snips and go to break the one-time clamp to check the hose out.... Purge valve breaks into two peices. Clean break tho. The left side cap thing broke off. The funny thing is that it broke with very little applied pressure by me. This leads me to believe that the leak was coming from the cap on the valve to begin with. Anyone have any experience with the purge valve breaking?

The inside of the cap had like two orange rubber diaphrams covering screened holes.

r0nd3L
12-06-2007, 02:59 PM
because my vac is 19-20 and idle and only 21-22 when in gear... i want to know if a boost/vac leak could possibly come from that gasket.

Isn't this normal vacuum?

ILoveT
12-06-2007, 03:00 PM
Why don't you just smoke it. That machine is fun!

audiFUEGO
12-06-2007, 03:20 PM
Isn't this normal vacuum?

yea well i was being generous with those numbers... The lower of those numbers are what i usually read.

audiFUEGO
12-06-2007, 03:20 PM
Why don't you just smoke it. That machine is fun!

thats what im trying to find out. Will the smoke/pressure test go beyond the TB?

creechsa4
12-06-2007, 03:25 PM
just make a pressure tester with pvc pipe 2" od and pneumatic air fitting & fit it to your intake piece after the maf & pressurize to 15-20 psi. it'll find your leak!

ILoveT
12-06-2007, 03:28 PM
Just hook it up directly to the manifold. There really isn't too much pressure there.

audiFUEGO
12-06-2007, 03:40 PM
Just hook it up directly to the manifold. There really isn't too much pressure there.

please explain... i havent seen any write ups where it get hooked up to the manifold.

only seen them where its hooked up to the TIP. And with the throttle closed i dont see how that would find any leaks after the TB. All those little black hoses that pose a threat are after the TB and need to be tested also.

salz2135
12-06-2007, 03:44 PM
where is the purge valve that you're talking about?

audiFUEGO
12-06-2007, 04:13 PM
where is the purge valve that you're talking about?

Its a 3-way valve that plugs into your:

1. brake booster
2. large L hose
3. Small L hose

^^^ if i remember correctly...

Its located at the top right of the IM

jlien08
12-06-2007, 10:16 PM
How about the "Z" hose from the block to the pcv system mentioned in my Head removal writeup?

Cant hurt to try that.

When I pulled my intake manifold off I found that 'Z' hard plastic piece crumbly, also the small hose running from the DV to the intake manifold, along with a few elbows and hoses. No wonder my car ran so shitty...

salz2135
12-07-2007, 12:38 AM
Its a 3-way valve that plugs into your:

1. brake booster
2. large L hose
3. Small L hose

^^^ if i remember correctly...

Its located at the top right of the IM



isn't that called the "suction pump"

audiFUEGO
12-07-2007, 08:05 AM
When i ordered it by part number off of WorldPac it was called "Purge Valve" in their catalog

Part # 058 133 753B

salz2135
12-07-2007, 10:12 AM
When i ordered it by part number off of WorldPac it was called "Purge Valve" in their catalog

Part # 058 133 753B

I've had my suction pump break. It looks like this:

http://www.audiworld.com/tech/eng67.shtml

audiFUEGO
12-07-2007, 11:00 AM
Yeah thats the one...i dont know why worldpac called it a purge valve.

Anyways i installed it and got a loud humming noise from my intake. Sound is coming right out of my cone filter. I removed the valve and plugged the hoses just to test... no noise. very strange..

I examined both valves (old and new) and bit closer, and found that on the old valve, The nipple that comes off at an angle (goes to PCV valve down under) is blocked and doesnt allow air thru. On the new valve, air goes freely thru that angled nipple. So basically the end that plugs into the Large L Hose see's boost and the angled nipple allows that boost to go down to the PCV. The old valve didnt do that. The old one may have been clogged but i dont know for sure how its supposed to be... and the weird noise is only with the new one.

I ordered another one and should be here in 10 min... well see how that one is.