hey guys, hopefully someone out there can help me get this fixed. here's my problem: when I first start my truck up in the morning with the ventilation fan engaged (as in the right-most HVAC **** is in any position other than AC or OFF), or when I engage the vent fan after the truck is started, I get this grinding noise that almost sounds like the teeth on two gears not meshing correctly. Then it goes away, and the fan begins to blow.
I have no idea what could be causing this, and my truck is out of warranty (43K miles). Can anyone help? Please?

 

If the fan is not blowing during this "griding sound" My guess is your blower motor is going bad. Eventually it will probably stop working all together.

 

You may have some debris in the heater box, pull the fan out and look for any leaves or debris.

 

Another possibility is debris in the HVAC plenum. It's common for leaves and twigs to find their way inside. The fan is direct drive from motor to impeller, so there are no gears to go bad.

EDIT: Too slow! Bill beat me to it.

 

Good minds think alike lol.

 

Ours do, too.

 

now thats funny wow ripped on himself and you bill haha

 

Ha ha! Yes, debris in there somewhere seems likely -- I agree with the others.

We had an old GenEdge meet years ago in Atlanta, and one of the guys complained about all this buzzing in his plenum. We took the fan out in Walmarts parking lot and there was a MAGAZINE inside the fan housing, I kid you not. Must have been in there since the factory, lo. Somebody reading on the job and having to stash it quickly?

It was a "hot rod" magazine, but I forget which one.

 

ok, debris in the fan box and/or blower motor on it's way out. that makes sense. now see, that's my problem! I cant think of all these reasons something isnt working right.
So, next question.....how do I open up the heater box to see if there is something in there?

 

You can pull the fan assembly out (underhood passenger side firewall area). Its flange is held in by 4 small screws and has an electrical connector and a hose going to it.

This picture is not a Ford blower fan but this is more or less what it looks like when it has been removed. You can't see the impeller when it's installed in the plenum:





This is the Ranger HVAC box with the fan out:

 

I had that for about a day, then whatever it was must have worked itself free. I'm assuming a leaf or the like. It was so loud it scared the crap out of me!

 

Depending upon where you live and where you visit.... consider this !!!
I have heard of people finding mice in their ventilations systems.....
When I purchased my '00 Ranger... I found twigs on my intake manifold and a couple of the wires going to a fuel injector had been nibbled upon where the insulation was missing.....
IF you start to get a STINK in your vehicle; this may be your problem !!!!

OR 4x4

 

Any progress Tracy?

 

had this problem twice while in warr. toke truck to dealer and each time they tell me that the fan motor is bad and repaired same. problem came back 6 months later after warr was out. toke out fan motor to check it out and there the leaves were in housing and fan. makes you think ford house was milking mfg for warr. - were i park at work is under trees, so i have learned to cover up wipers to keep out leaves during work day

 

hey guys. no progress yet, havent had time to pull it out and look inside. on the plus side, the noise has gone away. I drove my truck about 100 miles today, shut my truck down and started up again about a half dozen times, no noise all day. I'll still take that thing out here in the next couple of days, and let you guys know what I find. Thanks for all the help! God I love this place.

 

I'm coming in a little late on this, but I have an '03 XLT 4X4, and the very first day I had my truck it made the exact same grinding sound right after I started it. Same deal, it only does it if the hvac system is on @ startup. It lasts probably less than a second, but it's pretty dramatic sounding. Since it was brand new, I don't think it was leaves or other debris. I pointed it out to them once when I took it in for an oil change, and the reciept printout said "part ordered", but it never said what it was, and they never called to tell me the part came in. I take it in tomorrow for the works, rotation, and an maf sensor, so i'll bring it up and see what they have to say.