Let's face it, the blower fans in our trucks suck...er, blow. I know it's losing a step but it's quiet but I want to replace that 14 year old fan with a new one to try and get some extra flow. As is it I have to close the (3) passenger vents to get the kind of in the face flow I want and that's with the fan maxed out.

Yes, I plan on cleaning out the box when the fan is removed and hopefully brushing the face of the evaporator core thinking maybe it's got a light coating of dirt and debris that may be inhibiting flow.

However, if anyone has found one that is an improvement...I would greatly appreciate the tip. If I am going through the trouble of replacing the fan I would love to bolt in a better than stock replacement.

 

Not sure there is such a critter.... I suspect though, that your heater box is full of nature detritus.... that is impeding flow thru there. I can get a pretty stiff breeze out the dash vents, even with all of them open.

 

I have an idea I want to bounce off of you guys.

To preface this, the fan only blows one direction, therefor any dirt and debris that won't fit through the core gets kind of embedded on the face of the core which not only restricts airflow but it in a place that is extremely difficult to clean.

I was first wondering if there was a way to reverse the flow of air through the box to try and dislodge any of that debris from the face of the core. Without a cage fan with reversed blade direction, I just didn't see it an as option...

...and then I had a funny idea.

I am replacing the fan anyway, so I'm thinking of using the old housing which seals to the box and cutting a hole in it, roughly the same size as say a shop vac hose.

Now don't get too far ahead of yourselves...I'm not planning on trying to shop vac out the air box backwards through a gutted fan housing...I'm going to use a leaf blower.

My thinking is, use the gutted housing to seal the box so I can get backwards flow through the cores and increased flow in from the outside. I'll run a large diameter shop vac hose and seal it to the air input side of a leaf blower so it basically becomes a huge vacuum motor.

Leaf blowers move way more air than vacuums do and I'm thinking some brute force is what I would need to clean out that air box of everything I can't simply reach in and get.

Thoughts?

 

Leaf blower is an interesting idea...... (leave the passenger door open though...... )

One member used a shop vac stuffed up into the housing to clean out a bunch of pine debris that had accumulated in the box... Have a look in there with a flashlight, and mirror, see what you can see.

 

With all that debris in there, the evap and heater cores are going to leak soon enough on a 98. Forcing big time air in the box might just make them leak even sooner. I say, remove the box , clean it, replace both cores and install these. You won't have to worry about pine needles or any other debris getting back in there.

http://www.genosgarage.com/CAB-FRESH.../CFF-DG-0610K/

 

does your fan still have all the different speeds. if not, your "blower motor resistor" has burned out on the higher speeds. replace it.

 

If the resistor is bad/going bad, then it would only work on full speed. Most systems completely bypass the resistor on full speed.

 

There was no debris. Actually I was amazed at how clean it was inside that box. Neither core leaks right now so that's a good thing. A/C system was checked both with pressure overnight and vacuum overnight. Held fine after a new compressor was installed.

Because of the lack of debris, I didn't bother trying to vacuum it out.

It was so clean in fact I questioned if the fan was even original or not but sure enough it was the original Denso fan and it was in rough shape. Tons of black motor dust fell out when I tapped the shaft out of the fan cage. It still spun on all speeds but I new it wasn't going as fast as it should.

The new fan went in easy as usual...done several Mopar fan motors at this point and I'm getting quite fast at it. The new fan spins much faster moving a lot more air through the vents. I'm quite happy with the improved air flow...though when compared to other cars like even my Wife's Saab, the fan in these trucks is pitiful.

The one thing I saw that I may need to investigate, is what looks like a cabin filter behind where the glove box would be. I guess I have never paid it much attention. It's intact but probably clogged.

That brings up my final question...is that filter going to inhibit air flow through the system? What's the best way to get to it and ant tips to make the process go smooth for a first timer at it?

 

That filter thing is what controls whether your recirculating cabin air (max ) setting or allowing air from from outside.

 

My fan blows harder than a hooker for $50. I agree with the others, must be clogged with debris.