Weird clicking noise

[Extremesounds13]

Just last weekend my truck started making a weird clicking noise. The noise is coming from down by the heater blower motor inside the truck but is loud enough to be heard outside with the doors shut also. The noise only happens when I first get in the truck and turn the key on to cycle the glow plugs and the clicking starts immediately; it goes away after about 20 seconds. The clicking also happens after I shut the truck off, it also lasts for about 20 seconds. It doesn't matter if I turn the heater on or not while its clicking it does it everytime like clock work. Can someone help me out. Thanks

 

[NVW]

It's just the mouse that's driving the squirrel cage. Takes them awhile to get up to speed and to slow down.:smile5: Does it happen when the blower is shut off? Leo

 

[chrisk1500]

It is most likely the recirc flap not shutting properly.....

 

[Turbine Doc]

I've had leaves get in there also when the phosphor bronze bearing in blower motor starts to get age on them sometime you get a high freqq squeal, I change blower speed and usually calms noise in mine, or since I'm getting deaf after 30 years around turbines and other things that make loud noise, I don't notice it as bad once it gets even to higher freqs

 

[Burning oil]

It is most likely the recirc flap not shutting properly.....

Its what I think too. Look up under the dash on pass side. Way up in there is a small motor use to open/close the flap. Disconect it and see if the noise go's away.

 

[Matt Bachand]

Are you sure you're not hearing your lift pump/?? about 20 seconds prior to start and about 20 seconds after start on a 94 OPS would run after truck turns off.

Figured I'd throw it out there if your LP is starting to make a clunking noise vs its healthy purr.

 

[Extremesounds13]

I think you guys might be right on the recir door, I will check that out tomorrow. It does it every time I start and shut off the truck, whether the heater is on or not.

 

[chrisk1500]

It is the recirc door trying to go back to its 'starting' point....

 

[Bullseye240]

Since we're on this subject, does anyone have a diagram of the HVAC system under the dash that shows component layout. My Blazer only blows out of the dash right now and I need to fix it soon. Just want to same some time searching out the right part. thanks.

 

[GregAbell]

It IS the recurculation motor - I had the same midget hiding under my dash, beating on a plastic pot with his wooden spoon in my truck. I didn't fix it (yet) - I just disconnected the wires for now (I'm not going to be using the MAX button on my AC for awhile anyway).

Here's the link to when I asked this same question: http://www.dieseltowingresource.com/showthread.php?t=3670

 

[Extremesounds13]

So can you get one of these motors that runs the recir door at a local parts store or is it a dealer item only?

 

[buddy]

Ive had relays click that way too, in my other car.