Ford 4.0 howling

[Jameson]

Don't think this is going to be good...

Loud howling coming from front of motor. Just started last night. The first time it happend I had driven for a couple of hours, parked for 10 minutes, drove for 15 minutes, parked for 10 minutes, then drove for a minute and the howling started. I pulled over and shut the truck off. The noise stayed the same at 30 mph or idling on the side of the road, maybe got louder at idle. Upon re-start there was no noise and drove the 15 minutes home no problem. Today it started howling again 1 minute after I started driving. I stopped and shut the truck off and re-started without the howl. But then tried to drive maybe 4 miles total and it would continue to howl off and on. It would start when I would coast, then go away if I gassed it, and maybe or maybe not return when I went to coast again. As of right now it will do it sometimes when I start the truck, but usually I will have to give it some gas a time or two to get the howling to start.

Sure seemed like alternator, but does it with the serpentine belt off. With the belt on, and the motor howling, by the time I got the hood open, the motor would be going from idling kinda high, to spitting and sputtering, and would either die or resume at a much lower idle and no howl. With the belt off and it howling at idle it doesn't seem to want to die like before, but I haven't ran it like that for very long.

What kind of things can I check? Likely problem?

2000 Ford Ranger 4.0 Automatic 165,000 miles

Thanks

[fishnowworknever]

Check the Idler / tensioner pulleys and IAC valve.

Do you have a video of the howling?

My buddies "howled" and ran like [PoorWordUsage] at idle...and it was the IAC valve

[Jameson]

idler/tensioner pulley's are not in play. It makes the howl with the serp belt OFF.

I'll figure out what an IAC valve is and check it.

[fishnowworknever]

Found this:

http://www.fordrangerforum.com/how-submi...ir-control.html

[BoxMN]

Clutch fan? or is it "fan clutch"? I had that on my Ranger 2.8 and a buddy had it on his larger Ford long ago. It almost sounds like its a jet engine! Easy and relatively cheap fix if that might be it. Good luck.

[Jameson]

Found this:

http://www.fordrangerforum.com/how-submi...ir-control.html

LOL Me and you both.

Did it and no change. I had forgotten that I had replaced that part a couple years back.

[Jameson]

Clutch fan? or is it "fan clutch"? I had that on my Ranger 2.8 and a buddy had it on his larger Ford long ago. It almost sounds like its a jet engine! Easy and relatively cheap fix if that might be it. Good luck.

Someone please correct me if I'm wrong, but I don't believe the fan is in play with the serp belt off. It should be run be the serp belt, right?

[Scott K]

I would unplug the IAC, and see if it goes away, new doesnt mean it fixed the issue. If it is making the noise when you unplugged it, then you can rule it out.

[leech~~]

Water pumps going out!

[Jameson]

I would unplug the IAC, and see if it goes away, new doesnt mean it fixed the issue. If it is making the noise when you unplugged it, then you can rule it out.

It'll barely start with it unplugged, and to get it to stay running at all I have to work the gas pedal. Keeping it at about 3,000 rpm's and I don't hear any noise.

Start it with the IAC plugged in and it's howling and I unplug the IAC and it gets worse! Does this mean something?

And yeah the IAC is some aftermarket pile, not oem.

[Jameson]

Water pumps going out!

Does it with the serp belt off, don't think the water pump is moving at that point.

[Jameson]

IAC replaced, and it appears problem solved.

Thanks to everyone.