I am a new owner of my first truck and it is a 2003 Ford Ranger 3.0L Extended Edge with 138,000 miles on it. I keep getting a chirping noise coming from driver side of truck. It only happens when I have the AC on. I can turn AC to just air and the chirping stops. This only happens when I am driving. If I have my truck parked in drive with the hood up, I go and turn on AC full blast and I hear no chirping. I can see AC compressor turn on a few seconds after I start the truck and it is not cycling on or off every few seconds as some people I have asked told me it should do. AC air is ice cold so I should have enough freon. Now this chirping is not constant like a machine gun going off but just about every 5 seconds or so it would chirp. I have heard of bad camshaft sensors causing chirping but would that happen every few seconds and only when you are driving down the road with the AC on? Now I have noticed when truck has sat for a long time I get belt squeal for a few seconds and it then goes away. I think the squeal goes away when AC compressor starts because I observed this when looking for this random chirp. Any clues? Thanks for looking.

 

Welcome to FTE.


Good trouble shooting. The belt squeal is a good clue & suggests that all might not be right with the serp belt condition, or maybe the belt tensioner, or idler pulley bearing.
The OEM belt tensioner has molded in tension range indicators on its casting & the movable belt tension arm mark should be indicating between the max & min tension marks. If thats ok, inspect the belt under side ribs for missing chunks of rubber, if you find any, replace the belt. Cracks running across the ribs are ok, so long as no chunks of rubber are missing.
I'm running Dayton Poly Cog belts on my Ranger & Taurus & so far they're quieter than the OEM & to date are lasting longer without cracks in the rib area. Others have reported good things about the Goodyear Gatorback belt.


If all that checks out ok, have a look at the pulleys & belt for signs of contamination from oil, power steering fluid, or coolant, as they can make it slip. Lastly remove the belt & check the tensioner, idler & belt driven accessories pulleys for loose bearing wobble. All should be snug, offer slight resistance to rotation but have no side to side play/wobble, no free wheeling when spun. Check that tensioner & idler pulley & mounting fasteners are tight, same for the belt driven accessories mounting bolts. Lastly, with all bolts tight, all pulley edges should be in a straight line with each other so the belt is running straight in its groove & a straight edge can check the pulley face alignment. A bunch of thoughts for consideration, let us know what you find.

 

Thanks for the reply. I have examined the belt and there are no cracks or missing chunks on the side where the v grooves are located. But I did notice some wear on the side edge of the belt. Not the entire length of the belt but random spots along the edge facing forward. I see it has worn away the rubber and expose the thread reinforcement material. I did purchase a gatorback belt but held off installing it because I thought the belt looked in pretty good condition. Could the chirping every 5 secs be happening because when I am driving with the air on that would be the time when the belt and pullys are under the most stress? I was really afraid it was the camshaft sensor because I heard of horror stories that if that breaks it ruins the whole engine.

 

The edge belt wear is another good clue & suggests something isn't right with how the belt is running. Maybe its too wide, maybe not on straight in all pulleys, maybe a wobbly pulley bearing. Remove the belt, (there is a 3/8 square drive hole in the tensioner arm that a breaker bar, ect will fit in to relieve tension to make it easy to remove & install a belt.
Then inspect all belt pulleys for nicks, dents & pulley bearings for excessive play/wobble. Tensioner & idler pulley bearings deserve a spot on your suspect list.
Keep looking & you'll likely find the noise source.
When installing the belt, First route it over all the Walled pulleys, then slip its smooth back side over the wall less idler pulley last, using the breaker bar to move the tensioner arm to give slack.


The 3.0L cam sensor squeak will be coming from the passenger side, high up & back to the firewall end of the engine compartment, where the distributor used to be & its noise isn't usually associated with the AC compressor cycling.


The oil pump is driven through a coupling arrangement in the sensor assy, so if it seizes & strips the gears, the oil pump stops & the engine doesn't like that!!!!

 

Did you ever solve this enigma?

I recently traded for a 4x4 3.0 5speed ranger and it does exactly as you describe.

The belt looks good and the tensioner and idler bearings spin free and sound fine.