Bad Intake Manifold Check Valve?????
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 38
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From: St Louis Mo.
Bad Intake Manifold Check Valve?????
How would you know if the IMCV is bad? My ACV is making a horrible noise (like a slipping belt ) and there is air bleeding from the bottom of it where the silencer tube enters. Gasket seems fine, its very strange if anyone is familier with it but there appears to be a screw missing. Go to this and you will see what I mean 
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Emissions suck in St Luois, don't they. Squealing belt sound is probably a vacuum leak. Clean your ACV, reinstall and see if it still leaks. If not, there are plenty takeoffs around to be had.
HAILERS
Joined: May 2001
Posts: 20,563
Likes: 27
From: FORT WORTH, TEXAS,USA
That looks like a non turbo ACV.
They're easier to check out with the ACV installed on the engine.
To see if the Switching or the Relief diaphram are good/bad you can remove the two vacuum hose just above the ACV. Then install a spare piece of vacuum hose on the metal nipples the prior mentioned vac hose were connected to.
One at a time, suck on one of the nipples with your spare piece of vac hose. You should be able to hold a vacuum on each. If not, then the diaphram is bad inside the particular item your checking.
Most used ACV vent a touch of air at the large outlet at the bottom of the ACV. If it is venting a huge amount of air it's possible that the Relief SOLENOID outlet hose is not connected properly one of the two metal nipples above the installed ACV.
At idle, both vac hose going to the nipples above the ACV should have a vacuum on them. Check to see that is the case. Do NOT do this check with a cold engine OR the water temp switch disconnected from the Water Temp Sw at the bottom of a series four radiator.
They're easier to check out with the ACV installed on the engine.
To see if the Switching or the Relief diaphram are good/bad you can remove the two vacuum hose just above the ACV. Then install a spare piece of vacuum hose on the metal nipples the prior mentioned vac hose were connected to.
One at a time, suck on one of the nipples with your spare piece of vac hose. You should be able to hold a vacuum on each. If not, then the diaphram is bad inside the particular item your checking.
Most used ACV vent a touch of air at the large outlet at the bottom of the ACV. If it is venting a huge amount of air it's possible that the Relief SOLENOID outlet hose is not connected properly one of the two metal nipples above the installed ACV.
At idle, both vac hose going to the nipples above the ACV should have a vacuum on them. Check to see that is the case. Do NOT do this check with a cold engine OR the water temp switch disconnected from the Water Temp Sw at the bottom of a series four radiator.
Back from the dead. 
I just rebuilt my engine and now I'm having a strange noise from were aux actutars are(LIM area). The funny thing is, it doesn't make any noise when the engine is warming up. It runs and sounds just fine but when is gets fully warmed up, that strange noise appears and doesn't go away. It does sound like a squeaking belt. I have an S5 vert so could my problem also the ACV?
I just rebuilt my engine and now I'm having a strange noise from were aux actutars are(LIM area). The funny thing is, it doesn't make any noise when the engine is warming up. It runs and sounds just fine but when is gets fully warmed up, that strange noise appears and doesn't go away. It does sound like a squeaking belt. I have an S5 vert so could my problem also the ACV?
