engine making intermittant fog horn sound when idling

[Allen Reynolds 2]

Just noticed the other day I keep hearing a "fog horn sound" comming from the engine at idle (and when driving in trafic as well)



Has anyone ever heard this or know what it is.



Water lever in radiator is ok and temp is ok but it sounds like old school radiator over temp and blowing noise out the overflow hole.



Thanks

Po man

 

[David Sader]

Sounds like it could be your AC compressor cycling from off to on.