4.0L Engine chirp/squeal

[marriedmanw]

I have a noise coming from the engine bay of my 4.0L Explorer and I can't pinpoint the problem. The noise is more of a chirp but it doesn't get louder with engine speed. If revving the engine the noise is constant. When going down highway the chirp is a constant rythem. I've removed the belt and spun all the pullies and can't duplicate the problem. I put a new serp belt on and it stopped for about 3K miles. When idling it's not noticable, but when slightly increasing the idle it starts chirping. The best I can describe is chirp-chirp-chirp slight pause chirp-chirp-chirp.

Any recommendations are appreciated.

 

[vaderj]

if it doesnt change with rpms, than its probably something that has nothing to do with rpms .... something squeaky in the cab like molding? body or suspension mounts a little squeaky perhaps?

 

[rangerty]

i just noticed something similar with my truck after getting it running.. i think in my case it might be a pully baring.

 

[dorman68]

Possible camshaft synchronizer?

 

[TJH]

My '94 4.0 is doing the exact same thing. It is part of the ignition system & looks like the distributor gear shaft. Not sure what the correct name or part # is but I will know the part # in a couple of days. Apparently they do not make this part OEM anymore.

 

[Otto]

Does it sound anything like this, my trucks been makin this noise since I bought it and its driving me nuts. Really loud on cold start, goes away when the engine heats up.

http://www.youtube.com/watch?v=86GazNMlIRk&feature=channel_page

 

[marriedmanw]

Otto: No my truck doesn't should like that. Mine is more belt chirp and actually went away for awhile with new belt replacement. It is louder or more defined at cold start up but is still noticeable when hot. When idling it doesn't do it, but if the rpms are 1500 or higher it's there. I took it to the shop this morning so I'll pass along what they find.
When the replaced the belt in Dec they hand spun each pulley and didn't find anything wrong. Hopefully it's only and idler pulley or something simple. I did notice it's not as bad with the AC running so not sure if it's tied to the ac compressor some how.
I didn't look under the hood that much since it has extended warrenty and they have done me right with the extended warrenty plan so far.

 

[marriedmanw]

Ok, yesterday the dealership said it's the serpentine belt tensioner out of spec, but they didn't have new one in stock. They quoted $145 to replace, so I purchased a Dayco brand belt tensioner and the problem persists after replacing, so I put the OE back on. I noticed that the OE still has good spring when removing belt and the tick marks line up in middle of range. Next, I replaced the idler pulley and it still chirped over 1500 rpm, so I eliminated that also. If idling or cruising under 1500 rpm it's quite and smooth.
When I bought the truck in December I pointed out this problem to the salesman and he had the garage look and they advised they replaced the serpentine belt but it started doing it after a month. Currently the belt is a motorcraft brand and looks new (no cracks in ribs) so I don't know where to look now. I don't want have the shop replace the belt tensioner if it's not going to fix original problem.
Would it make since to replace belt with aftermarket belt like Dayco or Gatorback?

 

[marriedmanw]

Dorman68: Thanks for the tip.
I removed the Motorcraft serpentine belt and started the engine and no chirping so that was awsome. I went ahead cleaned all the pullies with a scour pad, then installed the new Dayco Poly belt. After starting it back up and revving about 2K rpms for 30 seconds at a time no chirping so far. I'm courious if the shop put some type of glaze on the belt that was already on the truck since it had a gloss look to it? I'll ride around this weekend and see if the chirping returns. Is the belt tensinor wear guide suppose to be in the middle position?

 

[joldtown]

I'm following your thread closely. Please continue to post results.

 

[marriedmanw]

I think it's solved...

After going to events over the weekend I drove about 100 miles and so far no chirping sound, so I hope it was only the belt. As mentioned before the motorcraft belt looked new as far as cracks in the ribs of the belt, but the other side was very shiney and the motorcraft letters (orginal white) were smugged with black so I think some type of glaze was used???

Joldtown - I replaced the idler pulley and belt tensioner since thats what the shop was going to replace and it still didn't fix my problem. After researching the camshaft synchronizer that Dorman68 suggested, I popped the belt off and ran truck (less than 1 min). With no chirping I replaced the belt and so far so good. I took off the aftermarket idler pulley and belt tensioner since the orginial problem persisted and put the OE back on and returned the parts. It looks like I went the long way around to find the problem, but I got good practice at removing the belt...

My Explorer only has 62K miles, so I surprised when the suggested the belt tensioner.

Thanks.

 

[cc98ranger]

I had the exact same problem this year with my truck and after changing 2 Dayco belts and 2 tensioners, I knew it was a belt problem, not any bearings squealing, just the belt, when I would hit the belt with some kids driveway chaulk the noise would be gone for a few days and then return. I finally changed the Dayco out for a Goodyear Gatorback belt several months back, noise hasn't been back. Now I think I am chasing the camshaft synchronizer since I have squealing coming from where that part is located at the front towards the drivers side. I have eliminated the belts, pulleys, and bearings once again. I had that part replaced on my wife's 02 taurus a couple on months back when it started doing the exact same thing. They say that is a popular problem with the 3.0-4.0 ford motors. Good thing I have a friend that is an ASE tech that I trust to work on my vehicles.