hissing sound from intake manifold...

[Sephroth57]

is it normal for your intake manny to hiss?? i think i found the problem thats been plaguing my car since i bought it. if you let the car idle and stand near it with the hood open u can hear a hissing, i always thought it was the air filter, but u stick ur head over the intake manifold u can clearly hear it coming from right near it. possibly the lower gasket is leaking, what do you think i should do to check this. just buy new gaskets take it off and change em and hope it doesnt leak still?

 

[terefic181]

More than likely just a vaccum hose leaking. Check all the hoses for cracks, diconections etc.

 

[jmakado]

is it normal for your intake manny to hiss?? i think i found the problem thats been plaguing my car since i bought it. if you let the car idle and stand near it with the hood open u can hear a hissing, i always thought it was the air filter, but u stick ur head over the intake manifold u can clearly hear it coming from right near it. possibly the lower gasket is leaking, what do you think i should do to check this. just buy new gaskets take it off and change em and hope it doesnt leak still?

do a boost leak test!! you can find out how at http://www.rmdsm.org/forums/showthread.php?s=&threadid=2916&highlight=boost+leak+test and www.vfaq.com. you probably have a leaky injector seal, intake mani. gasket, or some other thing. use a squirt bottle with soapy water to spray in the area where you hear the leak WHEN doing the test. also, when doing the test, move all of the injector harnesses a little and see if the noise stops....if it does, then one or more of your injector seals is leaking. once you find the leak, fix it and then test again and again until you find every last leak. chances are you have more than one if you have never done the test.

 

[Eclipsei95cl]

I had the same problem and it turned out to be bad gaskets on the intake manifold. So replace those or do a boost leak test.

 

[enid84]

I had same thing and i did boost leak test and found out that i had leak on all four injectors and many more. So if i was you i would hook up the tester and check it.

 

[Defiant]

Use a piece of vacuum hose, 4' or so. Put one end to your ear, and start poking the other around the leak area. You'll hear it in no time.

 

[jmakado]

did you do an intake leak test yet? what did you find out?

 

[sp00ln]

More than likely just a vaccum hose leaking. Check all the hoses for cracks, diconections etc.

Where are the vaccum hoses located?

 

[jmakado]

Where are the vaccum hoses located?

all the little black hoses running around your engine bay are vac. hoses.

 

[terefic181]

Where are the vaccum hoses located?

Here are some of them.

 

[terefic181]

Some additional ones if it's a CA emission car.

 

[terefic181]

Lost the pix above, here it is............

 

[terefic181]

sp00ln is just messing with us about the V hoses.

 

[sp00ln]

sp00ln is just messing with us about the V hoses.

No way :laugh: I was just looking for something specific!

 

[GSntncT]

you may also want to check the gasket between the intake manifold and throttle body. That's what causing my hissing sound earlier this year.

 

[terefic181]

No way I was just looking for something specific!

Ya...right.... ...but realy generalities are better than specifics when your first looking at a problem...agree???

 

[sp00ln]

 

[jmakado]

No way :laugh: I was just looking for something specific!

and to think...i was about to be a real asshole in my response.....

 

[sp00ln]

 

[miden]

I think you blew the welds on your intake manifold.

-M

 

[doodie]

Use a piece of vacuum hose, 4' or so. Put one end to your ear, and start poking the other around the leak area. You'll hear it in no time.

I'd like to see you find a 4 foot hose either diameter or length wise will still be pretty hard to use. But you can use that cardboard center from a roll of paper towel.

 

[WhiteCloud]

Why would it be hard to use a hose that is 4' long? It's vac line, it bends. It seems to me it would be one hell of a lot harder to use a paper towel cardboard thing. I don't like getting my head close to my engine while it's running if I can avoid it

I'm having a similar problem--Defiant were you talking about doing that stethoscope vac line thing while the engine is running or during a leak test or what?

 

[Defiant]

While it's running. 4' will give you enough length that you can stand up and keep your head away from the engine, and focus where you're listening to. Works great to put a piece of coat hangar wire on the end opposite your ear so you can steer it down along the bottom of the intake manifold and other iffy places.

 

[sp00ln]

Honestly, I think the kid thought of a real "VACCUUM" hose (like the ones you use to clean your carpet) when you said Vac hose.

 

[Defiant]

Ooo. That might be. Sometimes I forget how long I've been doing this.

Yes, I meant 1/8" engine vacuum tubing. You know, like you use to synchronize dual (or, triple if you're working on a later Austin-Healy, or a Jag 150) SU carburettors..... er, maybe not.

Sorry.