Brand New Engine Installed...

[74BroncoLV]

OK.....this Bronco is damn near perfect now...just got it back from the mechanic who put the new ford crate stock engine in it....exact replica....however i am driving it.....and something sounding like a belt squeak is CONSTANTLY there.....never goes away UNLESS....your cruising in a schools zone speed area with minimal throttle...OR even weirder.....if you turn the AC on it stops.....then when AC compressor cycles off it starts again the constant squeal.

any ideas before i take it back to mechanic? shoudl I use some belt dressing see if it changes?

 

[Rustytruck]

sounds like you isolated it to the clutch bearing on the ac compressor. when the air is off the clutch is disenguaged and the pully runs on this bearing. turn on the clutch it locks the pully to the compressor shaft isolating the bearing out and running on the compressure pump shaft bearings. If its the bearing and its squeeling like that it wont be too long before it goes south and takes out the belt and stops everything else running on that belt. usually goes in a smokey mess.
normally the squeeling belt comes on the belt to the powersteering pump so I would check there first.

 

[Lmfp]

Try just tightening the belt first. Is it a v-belt or serpentine setup?

 

[okie4570]

You could try spraying belt dressing to possibly locate which belt it is, but the belt dressing is usually not a fix. Every sqeaky belt I've had that was properly tightened, just required a new belt and the squeak was gone. My powersteering belt did this.

 

[74BroncoLV]

any thoughts on the first reply? the AC compressor bearing? If it was the bearing...shoudlnt the "sqeal" go away when AC off? and the squeal comes back when AC on?

 

[74BroncoLV]

it is a v belt and is new.....

 

[xcntrk]

What else is on the AC accessory belt?

If it's just the water pump or crank pulley and AC pump, then I would do the following:
A) try to tighten the compressor and belt.
B) if it's still squealin, try removing the AC belt altogether (assuming your alternator or PS is not on this belt)
C) if it stops entirely, then there's something wrong with the AC pulley or clutch (as posted in the first response).

 

[74BroncoLV]

ac, and alternator only I think....i sprayed belt conditioner on the belt at the compressor pulley and got it to stop....drove it for about 15 minutes and no noise, stopped parked went into store, came out started it and squeal was back, sprayed again and it went away.....

 

[73azbronco]

or try this, take the belt off and drive around the block.

 

[Rustytruck]

Does the alternator and the air conditioner have the same width pully grouve?
not all pully grouves are the same and since the factory didnt install the air conditioning system this opens the door for a missmatch.
That is also alot of load on a v-belt you may have to go to a 2 grouve alternator and or air conditioner pullys. If you have to tighten the snot out of a single belt to stop the squeel your alternator or water pump bearings wont last very long.

Not all belts are created equal, try a gates green stripe belt or sometimes the goodyear garor back belts are slightly wider and sit in the grouves better. Cheap chain store belts are crap avoid them.

 

[Rustytruck]

There is a bearing inside the clutch itsself that turns with the air condition off while the compressor isnt pumping. when you turn on the air conditioner the clutch locks up the compressor shaft and bypasses this bearing. think the oppasit reaction when you push the clutch peddle when you drive a stick shift the throw out bearing doesn't spin when driving but spins when you push the clutch in. the acclutch works the same way its just done with an electric clutch