Replaced water pump--now I notice hum at low idle.

[MtnHaul]

Hopefully this is a stupid question but my inquiring mind needs to know, and yes I have tried searching this and other forums.

I replaced my water pump with a Motorcraft unit and utilized riotwarrior's nice tech article to guide me through the process as I had never replaced a pump on the 7.3 idi. The job went smoothly--I really appreciated the fact that whoever replaced the fan clutch in the past did NOT use loctite of any color--but now when the truck is at low idle I notice a hum when sitting in the cab and to much lesser degree when I listen to the engine compartment with the hood up. The hum seems to disappear as soon I tap the accelerator pedal.

Now before I replaced my water pump the truck made quite a bit of noise/squeak at idle, so I slightly tightened my alternator and P/S belt. Now the P/S barely squeaks at hard left/right and the alt. belt still seems to have plenty of "slap" in it. I have tried adjusting the belt tightness but the hum stays the same. If I disconnect the factory air intake tube the hum changes when I listen with the hood up but doesn't seem to change if I listen in the cab.

Basically I am wondering/hoping that this hum is normal and that my previous squeaky setup was masking the hum. Any thoughts/suggestions are appreciated.

 

[mblaney]

Pop your belt(s) off and start it up; isolate if the noise is accessory related or just the nature of the beast.

 

[MtnHaul]

That's a good idea, thanks.

 

[icanfixall]

Or use some belt dressing on one belt at a time. Many years ago I used a stick of Door Ease. It appeared to be bee hive comb but who really knows what it was . It was about as hard as a candle. You just ran the engine and allowed it to rub one side of a belt. Be careful around the rotating pulleys and belts. Getting pulled in will not end well.

 

[MtnHaul]

Well that was an easy fix. I started the process of elimination by removing one belt at a time and starting the engine--thankfully I had to start with the A/C belt which seems to be the culprit. Guess I had it just a scosh too tight. It feels borderline loose when I press on it but there doesn't seem to be excessive play or slap when the engine is running, and the A/C works just fine. Sometimes the solution is so easy I look right past it. Thanks again.

 

[icanfixall]

Nothing to feel bad about an easy fix. Enjoy them when you get them. Glad the noise was found too.