I had a similar post a couple of months back and thought I had the problem taken care of - but it's back and driving me NUTS!!
I have 4.6 DOHC motor in my 47 Ford - I have replaced every front accessory (P/S Pump, Idler, Altenator and Water Pump) and new belt. The car starts and idles great - oil pressure is about 80-90 psi cold, drops to 30 psi hot but a flick of the throttle sends it back to 60-70 psi instantly. All seems good there.
Car drives good and shifts good it's got an AODE 4R70W.
My problem is at hot idle i get this steady squeal that sounds like a bad accessory bearing, when it bring it up to about 1500 rpm squeal goes away. At first I thought it was P/S fluid aerating (switched to Lucas Heavy Duty) seemed to help a little. The kicker is when I turn the car off - the squeal slowly diminishes like when you stretch the opening of a ballon while letting the air out for a second or two - doesn't do it every time - but most times.
I replaced the IAC valve because someone suggested that - the sound seems low middle of the engine, maybe even near the transmission but I can't think of anything that would be "spinning down" after the engine is shut off. I've checked all the vacuum lines twice but it really sounds metallic and not "a whistle" like I figure a vacuum leak would.
I've built over 10 cars and this one has me stumped!!! Any suggestions would be greatly appreciated!!
I have 4.6 DOHC motor in my 47 Ford - I have replaced every front accessory (P/S Pump, Idler, Altenator and Water Pump) and new belt. The car starts and idles great - oil pressure is about 80-90 psi cold, drops to 30 psi hot but a flick of the throttle sends it back to 60-70 psi instantly. All seems good there.
Car drives good and shifts good it's got an AODE 4R70W.
My problem is at hot idle i get this steady squeal that sounds like a bad accessory bearing, when it bring it up to about 1500 rpm squeal goes away. At first I thought it was P/S fluid aerating (switched to Lucas Heavy Duty) seemed to help a little. The kicker is when I turn the car off - the squeal slowly diminishes like when you stretch the opening of a ballon while letting the air out for a second or two - doesn't do it every time - but most times.
I replaced the IAC valve because someone suggested that - the sound seems low middle of the engine, maybe even near the transmission but I can't think of anything that would be "spinning down" after the engine is shut off. I've checked all the vacuum lines twice but it really sounds metallic and not "a whistle" like I figure a vacuum leak would.
I've built over 10 cars and this one has me stumped!!! Any suggestions would be greatly appreciated!!