intake leak
 

Recently i started hearing a high pitched squeaking noise from under the hood of my 1987 5.0 it sounded like a leaking intake manifold gasket. so i changed both the upper and lower gaskets. It still does it. when i shut the engine off you can definitly hear air leaking from something. anyone any ideas?

Re: intake leak
 

A cold air intake, or modified airbox will make that sound when you turn the car off... just a suggestion. Otherwise take it to the local guy and have it pressure tested. Heck, for that matter, I don't see why ya couldn't take some soapy water in a spray bottle and give it a couple of passes around the gasket. It shouldn't be any different than checking a tire. Just steer clear of the battery and distributor. If it bubbles in a certain place, its leaking. Anybody else had that problem?

Re: intake leak
 

thanks, i do have a cold air intake and a march ram air box and i just put a bbk 70mm throttle body on. after installing the throttle body i started to notice the sound. if i put my ear up to the raer of my 93 cobra intake thats where i hear the noise comming from. i replaced all the vacuum lines and intake gasket. still making the sound.

Re: intake leak
 

i think we have our answer if you notice the sound after installing the tbody...?

Re: intake leak
 

Yup, especially when you said BBK. I had the same Tbody on my car and at times it whistled so much you would think I had a blower on it. If the sound just started when you put on the BBK, I would say that is where it is coming from. It is normal for those to whistle, so nothing to worry about.

Re: intake leak
 

thanks guys! I put the old throttle body back on and the whistle stopped. so i will just deal with the whistle.

Re: intake leak
 

Turbulence in the airflow stream can create a whistle. This can be created by sharp edges in the air intake system, most notably when a larger throttle body is used on a stock intake that has not been 'Port Matched.' The air along the outer edges of the air intake system and throttle body hits the "wall" of the smaller intake manifold, creating turbulence that can cause a noticeable whistle. Other trouble areas can be the small vacuum ports and the IAC (Idle Air Control) valve port which may empty into the main bore of the throttle body. If these edges are square enough at the entry point of the bore, it

Re: intake leak
 

i have a cobra intake wich has a 7omm intlet. the throttle body is also 70mm. i check the iac and for any sharp edges. as far as i can tell there is nothing that should be causing problems with the air flow. i notice that the wistle is only heard at idle when the cars is warmed up.