Pressure testing the intake system .......Continued
pjrose at frontiernet.net
Sat Jul 31 09:13:59 EDT 2004
At 5:23 PM -0700 7/30/04, Chuck Pierce wrote:
>Continued from earlier:
>I fixed the hose and found that the crankcase pressure valve also
>leaks with the system pressurized, if I am correct that is not
>supposed to happen.
I believe you are _not_ correct about that. The procedure I followed
was to remove the hose ( from the forward outlet of the pressure
valve) and insert a plug (into the hose) during the pressure testing.
A wine-bottle cork fits nicely. This eliminates the leakage that can
occur via the crankcase breather system (dipstick, etc). Perhaps it's
possible to simply clamp off the hose (vise-grip?), instead of
inserting a plug.
>I went out and got a barbed tubing elbow to replace the crankcase
>pressure valve so I could continue to look for leaks.
>Found some air coming out from the dipstick, plugged that,
dipstick plug is unecessary if the crankcase breather is clamped
shut or disconnected as described (above). However, in any event
it's good to have a tightly fitting o-ring seal for the dipstick.
Even with a good o-ring, the pressure testing can "blow" the dipstick
unless the breather is disconnected.
>now it seems that I have some leakage around the injectors where
>they go into the intake manifold this is probably not a good thing.
I would think that's correct (not a good thing).
>I did not use more than 20psi for this testing. I did not seem to
>hear any leaks coming from the front end of the car( intercooler &
>connections). Pulled the spark plug wires out and found the #5 plug
>connector had some oil on the end. So this probably means the valve
>cover gasket is leaking ( at least the portion that seals the #5
>spark plug hole).
How old are the plugs, and are they the oem specified ones??? They do
tend to loosen considerably over time, so I'd advise removing,
cleaning and re-tightening each plug.
> Found some seepage at the rear of the valve cover also( while I was
Very common. Such seepage (and elsewhere) became evident within 6
months after I installed a brand-new gasket. Oil seepage into the
sparkplug ports is potentially more serious. I didn't have that
>Still do not think I have found why the car failed the smog test
>with really high hydrocarbons ( 193 ppm with a 120 ppm Mx at the
>low speed test).
Someone on the list was encountering the very same smog test problem,
not long ago.
Rochester, NY USA
mailto:pjrose at frontiernet.net
More information about the 200q20v