Front end shake as if driving over a washboard/rumble strip

[Blue~Go]

I thought of that too, but then figured they must already have drainage channels, since there is no guarantee water wouldn't come in even when they are in stock form. (Course maybe more were added.)

[caconcourse]

Good observation on water entrapment.

I didn't have the mounting hardware for the vent covers, since they were surplus, so I just mounted the shroud with four screws and new holes packed with caulk. I didn't try to seal the flange, so water can escape under the sides and back strip. If you bought a new vent cover, it comes with mounting hardware that includes brackets that connect to the side of the fantastic fan shroud, and the vent cover is slightly raised from the surface for water escape. You can also position the new screws so there is an intentional slight bulge in the side strips, to make sure it doesn't make a water-tight connection. You could also just cut off the back strip completely or cut notches, I just left it on to provide some shape retention.

I am assuming this will solve the problem by directing wind over the fan cover, but if it doesn't, my next version will save some of the second layer of the vent front, and I may cut some "shark teeth" shaped flanges like they use on 787 jet engine shrouds to reduce noise.

Update: I went out and poured a pitcher of water into the shround and all the water just seeped under the flange as expected, as fast as I could pour it in.


Clay

[1998chinook]

Thanks for that update Clay.

[Blue~Go]

Now I just can't wait for you to drive and test it out!

[caconcourse]

Now I just can't wait for you to drive and test it out!

Just completed a 4000 mile Yellowstone trip, and am happy to report there was no fantastic fan noise with the new shroud.

Also happy to report the Chinook rode like a new vehicle after new tires (Hankook Dynapro A/T in front, and H/T in rear), monroe shocks, and the mor-ryde spring replacements. Very nice ride and great handling.

[Blue~Go]

Great to read your report! Looks like a MaxxAir cover may be in my future. So easy!

I was parked in an open area with a 50 mph headwind (hello prairie), and I actually went up on the roof with a little mockup fairing which I taped on. But I couldn't really tell if it was helping because there was so much other wind noise. Having a known good/easy fix is pretty sweet.

[1998chinook]

Thanks for the update. Going to order a cover this week. I probably just missed you in Yellowstone. I did see one other Chinook while I was there.

[caconcourse]

Thanks for the update. Going to order a cover this week. I probably just missed you in Yellowstone. I did see one other Chinook while I was there.

We did meet a twin Chinook in Yellowstone while waiting and passing a herd of buffalo crossing the road. The lady driver had the biggest smile I've ever seen as we passed and waved. We saw a total of four Chinooks on the trip, that one, and three driving up 101 in Oregon. One was another twin (1997-2002 Black/Silver Concourse) and one was an earlier 90's Concourse and one was a Premier.