Any ideas I'm stumped

[HookMeUp]

Well I have a GM 5.7 which has a leaky rear seal and a bad case of oil blow by on cylinder #4...
last night I started the truck and there is a whistle sound coming from the passenger side exhaust. I would say it co-sides with cylinder # 4 also. The motor starts and runs fine but I don't know for how long.

(I know the engine needs to be rebuilt that point is mute. I'm in a crunch for time and have minimal funds till May)

Any idea what is causing the whistle sound?

 

[str8axle55]

Loose or broken spark plug, ex manifold cracked?

 

[manchildau65]

vacuum leak? spray quck spurts of carb/choke cleaner around the base of the carb and see if you have a vacuum leak (engine RPM will change). Sounds like the engine is in rough shape, check all your vacuum lines for cracks and such.

 

[HookMeUp]

not sure I'm clear in the original post the whistle sound is coming out the exhaust if standing by the motor it sounds fine behind the truck you can hear a whistle coming out the exhaust in pulses any ideas to what would cause this phenomenon?

 

[1BEATK5]

a small exhaust leak can make a whistle. i've heard them before. not normally at idle. usually under acceleration.

 

[Blue85]

It's an exhaust leak. Do you have A.I.R. tubes or a heat riser valve?

 

[HookMeUp]

It's an exhaust leak. Do you have A.I.R. tubes or a heat riser valve?

To be honest I don't think so. Not that I'm 100% correct either

 

[ryoken]

if it sounds like it's coming from the tailpipe, try the dollar bill trick.. to check for a bad exhaust valve...

if the noise is up front, it's an exhaust leak around the manifold somewhere...

And a leakdown test will verify the cylinder issue...

 

[HookMeUp]

if it sounds like it's coming from the tailpipe, try the dollar bill trick.. to check for a bad exhaust valve...

if the noise is up front, it's an exhaust leak around the manifold somewhere...

And a leakdown test will verify the cylinder issue...

Care to enlighten me whats the dollar bill trick?

 

[ryoken]

hold a bill over the tailpipe loosely, if it gets sucked up to the pipe at any point, it generally means a burned exhaust valve... consistently pushing off the pipe, normal...

 

[HookMeUp]

hold a bill over the tailpipe loosely, if it gets sucked up to the pipe at any point, it generally means a burned exhaust valve... consistently pushing off the pipe, normal...

Well its a bad exhaust valve to say the least...looks like it's time to park it and start the tear down once I find another dd.

 

[andyblack]

if it sounds like it's coming from the tailpipe, try the dollar bill trick.. to check for a bad exhaust valve...

My truck has been doing dollar bill tricks the whole time I've owned it. It's usually sucking dollar bills down the gas tank filler neck and blowing them out the tail pipe though.