custom truck mods

"Fresh air mod"

The complete cowl assembly	Driver side of sheetmetal under cowl
Passenger side of sheetmetal under cowl	The concept - cutting out the chads
Partial results - driver side	Partial results - passenger side
Air intake cover - remove for access	Air intake exposed with screen
Air intake screen closeup

how to perform this mod

So, enough talk. I was sick of the fans blowing hot air into the cabin - it's hot enough around here in the summer. Several people have performed what is basically the "fresh air mod" which alleviates this problem. No one has reported any problems with this mod so far, myself included.

The mod basically consists of labor, and aside from that - costs nothing. The actual labor is the process of cutting out the "chads" (malformed "grilles" in the air vents found on the cowl, under the windshield). Complete time for the mod can range from a half hour to three hours, depending on how much care you take in the various steps, outlined below and perhaps more so by the number of chads you wish to remove.

The problem is that the air vents are blocked too much by these chads, forcing the air to be pulled from around the engine compartment, pre-heating the incoming airstream. This means even hotter air in the summer coming into the cabin, whether it's fresh air or entering the air conditioning system.

The payback from this mod is definitely worth the effort as the air coming from the vents is now much closer to the actual outside air temperature, and no longer heated by the hot engine compartment. Air conditioning with this mod is also improved dramatically. Using the "recirc" (recirculation) mode of course bypasses the outside air vent and is not affected by this mod.

You could get by with only cutting out say, the center row of chads from each section and stop there - or take this mod to its full conclusion and even better results. To do this, remove ALL of the chads from the cowl pieces. If you do this, you'll need to fashion a screen for the air intake that sits under a black plastic cover on the passenger side. A piece of flyscreen draped over the intake and held in place with a nylon tie will ensure that you don't suck up any twigs, bugs, leaves or other debris into your intake fan - very important! Otherwise you'll get a lot of debris in the cabin, or clog your air intake filter prematurely - possibly damaging your fan in the process.

An optional step is to seal two small round holes found on the inner fenderwell on both sides of the truck. This serves to further restrict the pre-warmed air around the engine from getting pulled into the air intake. The hole on the driver side can be reached by hand and readily sealed with a little duct tape. The passenger side is a whole different story and requires removal of the wheelwell lining underneath. I haven't patched up this side, and the mod seems to work very well as-is, so I don't really think this step is absolutely necessary. Your call on this one.

Basically, the procedure is as follows:

1. Pop off the covers over each end of the windshield wiper arms
2. Remove nuts from, and including the wiper arms
3. Pull/Pry up conical rubber base from antenna and remove
4. Open the hood and prop it open as normal
5. Carefully take rubber strip off back edge (held on by little plastic "T" snaps)
6. Pull up outer corner of cowl - you'll see the white pin holding it down
7. Keep pulling up gently around each of the other pins (you'll feel them)
8. Remove the cowl from the each side the same way
9. Remove little plastic "T" snaps from cowls that hold weatherstripping
10. Clean up the whole area and wash out the channels with a hose
11. Take a new blade in an X-Acto knife and carefully cut out each "chad" from back of cowl piece
12. Clean up the holes you've made (hold up against light or sky for contrast)
13. Slowly move a propane torch over the BACK of each cowl piece where the cutouts are
    (this darkens the plastic and makes it shiny again, hiding your handywork)
14. Apply "Back to Black" over cowl pieces, allow to dry and then buff with cloth
15. Clean up rubber weatherstripping and apply silicone spray evenly
16. Remove black cover over passenger side vent hole (three screws)
17. Fashion for the air intake a screen using nylon/metal window mesh, secure with nylon tie
18. Re-install black cover from previous step
19. OPTIONAL: Apply duct tape over small round vent hole against inner fender, driver-side, inside cowling
20. Snap cowls back into place carefully by applying pressure over each of the pins
21. Insert "T" snaps into each hole in rubber weatherstripping
22. Install weatherstripping into place by pressing on top of each "T" snap
23. Re-install conical rubber base to antenna - align the groove with tongue on antenna base
24. Re-install wiper arms to previous position (rotate them a little and feel for the splines to seat some)
25. Tighten nuts to wiper arm shafts and re-install covers - test to make sure they're right

That's it! Enjoy! 

NOTE:   There is a service bulletin which specifically addresses the problem of excessively warm air through the vents. It only applies to the 2000/2001 model years. Have your dealer look up in their "ASSIST database" for "2000 Xterra, Heater/AC section and excessive heat." The bulletin ID# is "NTB02-031" which will report part numbers of replacement cowl pieces: "66811-9Z001" for the left side and "66810-9Z001" for the right side. The originals are listed as "66810-9Z000" and "66811-9Z000" respectively. If you're still under the 3yr/36k miles warranty it's a free fix. I'm not sure about the extended warranties.