Folks,

Have a 2002 Ford Explorer 4.0 6cyl. w/ around 150K

I recently started hearing a little chirping noise when starting from cold. The rate of the chirping increases with the rpms (reving in neutral or when speeding up while driving). The sound usually goes away after things warm up.

Doing some research, the most suggested cause for such chirping is something called a Camshaft Position Sensor. Information mentions that this item can either need lubrication or to be replaced.

I was going to try lubrication first....then if the problem persists...replace.

My biggest issue is locating it on a 2002 4.0 Explorer (4 door, 4wd). I've read different reports for different Year models (mostly 97-2001)...which often include pictures. But I can't find ANY pictures for the 2002 4.0

QUESTION: Does anyone know where it is located on my 2002 6cyl model? I read one account of it being on top of the driver's side valve cover....and I DO see an item in that location secured by one bolt..and it does have an electrical wiring harness attached....but I'm not sure...and have not seen any photos that look like my engine.

I've attempted to upload a picture of what I think maybe be the sensor (circled on red).



Any advice greatly appreciated.

-Kev100

PS: I've also come across an item called a "CRANKshaft position sensor".....are these different items, and, if so, does the crankshaft p.s. also "chirp" when needing lubrication or replacing ?

 

Which 4.0L engine does your Explorer have, the OHV or the SOHC?

The crankshaft position sensor is located, surprise, surprise, at the crankshaft which is low in the engine. The camshaft position sensors sense the rotation of the camshaft which is higher in the engine. How high depends on which 4.0L engine your truck has.

-Rod

 

It's a SOHC (2002) 4.0 6 cyl gas only (Not the Flex-Fuel version)

Also....any advice on which of the 2 is most likely associated with the chirping noise described in the first post ?

-Thanks

 

On the 2002 SOHC there is only one CMP sensor and it's the part you circled above. I don't find a detailed description of how this CMP works. From the looks of the part and it's location, it would appear to be a hall effect sensor versus a mechanically driven sensor. If it's hall effect it would not be likely to cause a noise like the older mechanical sensors would.

I'd suggest on a cold start when you hear the chirping to spray the serpentine belt with some brake cleaner to see if that, even momentarily, changes the chirp. You might also try removing the belt on a cold engine and spin the pulleys that will easily spin manually to see if any are rough or noisy.

-Rod

 

Thanks for that info....I was able to pull that part out to get a look at it...it did not appear to be something that needed lubrication.

Any advice on where the CRANKShaft position sensor on this model is located, specifically.....and, if this model actually has a CAMShaft Sychronizer (3rd image)

Here are the 3 different parts I've come across for that model:

CAMShaft Position Sensor for 2002 Explorer:



----------------

CRANKShart Position Sensor for 2002 Explorer:



----------------

However...for the CRANKShaft position sensor of other models, I kept expecting the part to look more "mechanical" - like the one below (which I think is a CAMShaft Sychronizer):

CAMShaft Sychronizer (specific model unknown)




- Thanks

 

Your truck does have a Crankshaft Position (CKP) sensor but it too is a hall effect sensor, not a mechanically driven sensor. Unless the harmonic balancer or a the belt has a defect, it would not be the source of the squeak either.

The sensor shown in your 3rd image is the type of CMP sensor that would be used with an older style engine block and it would be mounted in place of the old mechanical distributor.

-Rod

 

Thanks much for that...that must explain why there's no how-to info to be found for that 3rd item for a 2002 model.

The chirping sound will be there in the morning (when first starting....and will persist while driving.. Then, after driving a few miles......shutting DOWN the vehicle....then starting back up a little later.....the sound is then usually gone (until the next morning).

As mentioned earlier, the rate of "chirping" seems to increase with the RPMs while either stationary in Neutral or when driving.

I tried to capture that chirping sound on a video (hope it's loud enough) and post it (a link to YouTube). Is that Chirping sound distinctive enough to point to any likely condition ?


-Thanks

 

To me that chirping noise, and your description, still sounds like it could be a belt / pulley noise.

If that were my truck I'd remove the serpentine belt on the engine when it's cold, start it up, and see if the noise is gone.

-Rod