Help Diagnosing Belt/Pulley Squeal on '94 XLT

[luvmonterey]

Hi all. Over the last eight months, my '94 XLT has developed some intermittent belt/pulley squeal. It comes and goes, but seems to be getting more frequent, and I'm not sure what is causing it, or how to diagnose. First thing I did was to replace the belt, as I had a spare. That did nothing, so I don't think that's the issue. It's funny, but it seems to happen consistently on the same stretches of road. I'm thinking it may be the water pump, but I don't want to go through the process of replacing it on a whim. Can anyone provide me with suggestions on how to narrow down an identify the cause? Thanks!

 

[Turdle]

Remove the serpentine belt and run the engine for a short time. Less than 1 minute won't hurt anything.
If it still makes the squeal-squeak, I would suspect the cam sensor-oil pump drive unit.
While the belt is off, check the pulleys. Spin them by hand and notice if one of them makes any unusual noise compared to the others.


You can also spray some water on the belt while it is squeaking to see if the sound changes, or goes away. This will tell you it is a slipping belt.

 

[luvmonterey]

Remove the serpentine belt and run the engine for a short time. Less than 1 minute won't hurt anything.
If it still makes the squeal-squeak, I would suspect the cam sensor-oil pump drive unit.
While the belt is off, check the pulleys. Spin them by hand and notice if one of them makes any unusual noise compared to the others.


You can also spray some water on the belt while it is squeaking to see if the sound changes, or goes away. This will tell you it is a slipping belt.

Thank you for the suggestions. I will attempt to give this a try. On issue however, is that frequently the noise is intermittent, and does not start until after I have driven for a bit. It is not often that the noise starts immediately upon start up. It does seem to be getting more frequent however.

 

[Rhett]

Thank you for the suggestions. I will attempt to give this a try. On issue however, is that frequently the noise is intermittent, and does not start until after I have driven for a bit. It is not often that the noise starts immediately upon start up. It does seem to be getting more frequent however.

Sounds like the cam synchronizer to me. Mine would do that -- quiet on startup, and would only make noise after a few minutes of driving.

 

[luvmonterey]

Sounds like the cam synchronizer to me. Mine would do that -- quiet on startup, and would only make noise after a few minutes of driving.

Is this something I should be concerned about, or need to address? I don't like my truck to make noises it shouldn't.

 

[Turdle]

Unfortunately, yes. Since it drives the oil pump via the camshaft. A noisy bearing is an unhappy bearing. Since it is a clevite type bushing (bearing) , cleaning the shaft and bushing bore might just be the trick that will work.
However, changing this is a chore, so putting a cleaned or cheap one back in is a risk of a lot of labor. The location on the top rear of the engine requires removal of the upper intake manifold. This chore requires egr tube to be removed from the upper intake, however you might be able to just move the upper over to the driver side enough to see what to do.

Earlier Explorers use no actual sensor there but have the same style oil pump drive unit, it is just a stub. Those can be changed by feel sometimes depending on the unit.

Yours has a sensor on top,so, I do not think there is enough clearance to get it to slide up enough for removal. Since this thingy also provides injector timing signals, It does have a critical alignment which needs performed.
I think if you can take a picture of the internal to external orientation of the old sensor, and get the new one in the same orientation, you'll be very close.

 

[luvmonterey]

Unfortunately, yes. Since it drives the oil pump via the camshaft. A noisy bearing is an unhappy bearing. Since it is a clevite type bushing (bearing) , cleaning the shaft and bushing bore might just be the trick that will work.
However, changing this is a chore, so putting a cleaned or cheap one back in is a risk of a lot of labor. The location on the top rear of the engine requires removal of the upper intake manifold. This chore requires egr tube to be removed from the upper intake, however you might be able to just move the upper over to the driver side enough to see what to do.

Earlier Explorers use no actual sensor there but have the same style oil pump drive unit, it is just a stub. Those can be changed by feel sometimes depending on the unit.

Yours has a sensor on top,so, I do not think there is enough clearance to get it to slide up enough for removal. Since this thingy also provides injector timing signals, It does have a critical alignment which needs performed.
I think if you can take a picture of the internal to external orientation of the old sensor, and get the new one in the same orientation, you'll be very close.

Thanks for the info. Is there a way that I can further diagnose this as the issue? Or, do I need to eliminate pulleys or the water pump? I haven experienced a failing water pump on this Explorer so I don't know what it would even sound like.

 

[Rhett]

Thanks for the info. Is there a way that I can further diagnose this as the issue? Or, do I need to eliminate pulleys or the water pump? I haven experienced a failing water pump on this Explorer so I don't know what it would even sound like.

Yes, by using a mechanic's stethoscope (pretty cheap to buy) and listening to each pulley on the front dress. It may sound strange, but it works.

Here is my thread on the noisy cam synchronizer. As you can tell by the thread title, I too thought it was the water pump -- but it was not, AND on top of that I changed almost everything else in the front before I figured out it was the cam synch:
http://www.explorerforum.com/forums/index.php?threads/bird-chirp-water-pump.146928/

As for changing the camshaft synchronizer, Turdle pretty much said it all. I was forced to remove the upper intake manifold to allow room to get the old cam synch out. It is a time consuming job, and making sure the cam synch is aligned properly is difficult for a lame-brain like me. Marking its position before removal, and taking close up pics, is a must.

Anyway, hope that saves you some money, not changing parts that aren't broken.

 

[luvmonterey]

Yes, by using a mechanic's stethoscope (pretty cheap to buy) and listening to each pulley on the front dress. It may sound strange, but it works.

Here is my thread on the noisy cam synchronizer. As you can tell by the thread title, I too thought it was the water pump -- but it was not, AND on top of that I changed almost everything else in the front before I figured out it was the cam synch:
http://www.explorerforum.com/forums/index.php?threads/bird-chirp-water-pump.146928/

As for changing the camshaft synchronizer, Turdle pretty much said it all. I was forced to remove the upper intake manifold to allow room to get the old cam synch out. It is a time consuming job, and making sure the cam synch is aligned properly is difficult for a lame-brain like me. Marking its position before removal, and taking close up pics, is a must.

Anyway, hope that saves you some money, not changing parts that aren't broken.

Thanks for the info. I actually have a mechanics stethascope so next time it squeals while I'm parked I will see what I can figure out. I too, hate changing parts that aren't broken. I have a brand new starter. Turns out I needed a battery, so I have a new one of those too!

 

[Centaurious]

There are two bolts that hold the Sensor on top of the cam synchronizer. You can try pulling it and oiling the bearing. I would suggest 20 to 30 weight oil.