How to make an effective, durable, reusable and easily removable bug screen to protect AC condensor fins

[seafish]

Some years ago, I constructed a durable, effective, easily cleaned and fully reusable bug screen out of stainless steel mesh and aluminum channel to help keep the cooling fins of the AC condensor on my 2005 Dodge Ram clear of debris. Recently, with the front end of my 2005 Jeep KJ CRD all torn apart for a timing belt replacement, and a brand new AC condensor also installed, I realized that I wanted to do the same thing for it.

On the truck, the bug screen is readily accessed for cleaning by removing only two screws at the front of the Kilby Tool Tray that I had previously installed over the radiator. On the KJ, however, I needed to be able to easily remove the topmost/horizontal section of the headlight panel support frame that covers the top of the electric fan and AC condensor. For reference, the entire headlight panel support frame is the “T” shaped piece of metal that both the plastic headlight/foglight panel and the hood latch mechanism bolt to.

Here it is circled in red --

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[seafish]

Removing ONLY the top horizontal piece of this headlight panel support assembly is the trick that allows easy access to the narrow space between the back off the electric cooling fan and the front of the AC condensor. And this space is EXACTLY where the stainless steel bug screen slots into while still leaving enough clearance between the spinning fan blades and the condenser fins.

The complete "T" shaped support member is normally removable ONLY AFTER the bumper cover and headlight mounting panel are also already removed from the front of the Jeep. This is because there are two screws at the bottom of the leg of the “T” that attach it to the bumper frame and are located under, and hidden by, both the bumper cover and the headlight mounting panel.

That said, while I had the entire support piece already removed from the vehicle for a timing belt replacement, it became obvious to me that the top section of the lightweight frame could be easily modified to be readily removable all by itself simply by drilling out the two rivets that connect the head of the “T” to the leg of the “T” and then replacing the rivets with two short bolts. These two bolts (actually 1/4” x 20 x 1/2” panhead machine screws) still hold the frame support securely together, but can also be removed from the front of the vehicle without removing ANY other parts first!!!

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[seafish]

In short, drilling out these two rivets and replacing them with two machine screws and nylock nuts is the simple key to this project.
That said, it's important to note that there is only minimal clearance between the rivets and the underside of the closed hood (which is likely why rivets were used in the first place), but by using only short screws and nylock nuts, and then cutting off any of the bolt flush with the top of the nylock, there was about 1/8” clearance between them and the underside of the hood. When I replaced the standard nylocks with some even thinner profile nylocks from McMaster Carr, that clearance increased to an even healthier 1/4”

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[seafish]

Despite my doing this modification with the support member already removed from the the vehicle, in my opinion all of this work can still be done almost as easily and, more importantly, still without going through the trouble of first removing the bumper cover, headlight trim panel and headlight mounting panel from the Jeep.

That said, if you are doing this modification with the frame support member still fitted in the vehicle, then careful attention MUST be paid when drilling out the two rivets, so as NOT to damage the AC condensor while drilling towards it. This can be done simply by placing a piece of scrap wood or metal between the back of the rivets and front of the condensor while drilling the rivets out. Furthermore, at least on my 2005 KJ, the rivets were aluminum and drilled out quickly and easily with a 5/16” drill bit. The 5/16” drill bit then left perfect holes for the two 1/4-20 x 1/2” panhead screws that took their place.

Once the two rivets are drilled out and replaced with the two panhead screws and nylock nuts, then the four OEM panel screws that hold the support member to the to top of the engine compartment, and the two bolts that replaced the rivets, are quickly and easily unscrewed while leaving EVERYTHING else untouched and secure in place on the Jeep, INCLUDING the dreaded clips on the headlight vanity surround panel.

And with the top section of the support piece removed, access is readily available to the otherwise inaccessible space in which to insert the woven mesh bug screen!!!

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[seafish]

Since the space under and behind the support piece is fairly inaccessible and relatively confined when if it is installed, I decided to epoxy the panhead screws in place, in order to facilitate any future removal and reinstallation of the bug screen for cleaning, without having to fumble finger around holding the backs of the screws tight while turning the nylock nuts.

So after cleaning both sides of the frame around the newly drilled holes, as well as the heads of the machine screws, with acetone, I added 4 small internal tooth lock washers (one on each side of the panel for each machine screw), and then used some JB Weld to lock everything together. The lock washers added some additional texture and purchase for the epoxy to hold onto. In the pic below, on the right, you can almost see one of the four lock washers buried in the epoxy.

NOTE: One could also use a properly sized thin spring push nut instead of the toothed lock washers, and this would obviate the need for clamping while the epoxy dries, but since I didn't have any on hand , I just used the lock washers and some spring clamps.

While this step might seem unnecessary, taking the time to epoxy the screws in place now will make removing and reinstalling the header piece in the future ridiculously fast and easy.

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[seafish]

With the screws clamped in place and the epoxy drying, I turned to fabricating the mesh screen itself.

While I had used a somewhat finer opening screen on the truck (with its distinctly oversized Cummins cooling system), on the KJ CRD I did not want to restrict too much airflow while still catching bugs, so I chose a 5 x 5 per square inch woven stainless mesh . The openings in the mesh are between 1/8” and 1/4” (5mm) and the wire is a fairly fine 21 AWG (.7mm), but being made from stainless steel, and also being woven, this mesh is thin, fairly rigid and still allows plenty of airflow through it (85% opening).

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[seafish]

I bought two pieces of 24” x 24” #5 woven stainless mesh from Amazon for all of $25 delivered and then snipped one of them down to 18” wide by 20” high. I also cut two pieces of 1” high x 1/8” gap aluminum J channel that I had lying around to 18” long.

IMPORTANT NOTE: in order to fit into the narrow space, the channel used to frame the mesh screen CANNOT be any thicker then 1/4”.

ALSO NOTE: I did NOT use use any channel to cover the vertical/side edges of the mesh screen because it seemed unnecessary and might have made inserting the screen in the allowed space more difficult.

I then applied a line of Sikaflex polyurethane caulking to the inside of the aluminum channel and fully inserted both the top and bottom edge of the mesh into its own section. While I also used the bench vise to lightly crush the channel around the screen after it was inserted into the mastic, with hindsight this step was unnecessary as the Sikaflex is an extremely flexible and durable polyurethane glue.

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[seafish]

With hindsight, gluing up the J channel on BOTH the top and bottom edges of the mesh was likely unnecessary.

In fact, one could simply use the unframed screen all by itself, but I liked the way the aluminum channel sealed off the sharp cut edges of the woven mesh. My thinking was that the channel would keep the woven mesh from unraveling over time and also prevent the sharp wires of the cut mesh from MAYBE eventually wearing into the ends of the PS hose connections where it was resting at the bottom of the AC condensor. At least, at the time, that was my justification for the extra trouble.

 

[seafish]

Finally after both the epoxy and mastic had dried, I used some stainless washers and thin stainless nylocks to reassemble the panel support piece and reinstall it on the Jeep for further test fitting. Despite measuring twice, cutting once and also previously test fitting the screen with channel, when it came time too slide the newly made bug screen into its gap, the fit between the J channel and fan frame was a single, coarse “RCH” too tight!!!!

GRRRRR!!!

Rather then abandon the already framed screen and simply trim down and use the second piece of mesh as a plain, unframed insert, I decided that I would add an oversized metal washer BEHIND each of the 3 electric fan mounting bolts in order to push the fan forward 1/16” and allow the framed bug screen to more easily slide into and out of place without having to lightly forcing it past the plastic bracing on the electric cooling fan.

In fact, removing the fan bolts, then sliding these large washers into place behind the fan legs and reinstalling the bolts with the headlight assembly and fan already installed was actually the hardest and most time consuming part of this project!!!

Was too frustrated to take any pics at this point...

 

[seafish]

I realize that using a section of the aluminum channel to frame ONLY at the top of the screen would have still kept the woven wires from the remote possibility of loosening up over time, would have still given me a protected edge from which to handle the bug screen, and ALSO would have saved me all the frustration of installing those washers behind the already installed fan.
But since I had already glued both the top and bottom of the mesh into the aluminum channel, and I actually liked the way it looked and worked, I went ahead and used the washers.

IMPORTANT NOTE: If you are doing this modification with with the support frame still in the vehicle, and the front of the Jeep remains fully assembled, then simply SKIP gluing the aluminum channel section onto the bottom edge of the screen and you will NOT have any fitment issues and you will NOT have to place any washers under the fan mounts!!!!

 

[seafish]

From start to finish this simple fabrication/modification cost less then $40 and took LESS then 2 hours to do...(excluding glue drying time)

In fact, it took me longer to write this thread up and edit the photos then it did to do the actual work

Here are a couple close ups of the finished bug screen installed --

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