Repairing leak at Scamp furnace vent

[WDavidG]

We returned from our spring NF trip, a rainy drive back, with noticeable wetness in the driver’s side dinette storage and in the cabinet under the sink.

A series of experiments with a hose indicates the leak is most likely at the furnace vent with water flowing down on the wheel well and then draining both forward and to the rear. My only hesitation about this as the source is that the caulking (the scamp is 3 years old, so it is original factory caulk) appears to be good. But the leak is substantial so I’d like to remove the cover and re-install it with some butyl tape and hope it is indeed the source.

Do any of you have experience removing the vent cover? The vent cover plate is riveted with six rivets. I’m afraid if I drill out the rivets, an internal furnace component that is also held by the rivet may shift and I won’t be able to line everything up with a new rivet. I’m just not sure what things look like in there.

Here is a photo of the vent cover (it got turned sideways - not sure how to fix it). Thanks for whatever advice you can provide.

[Eddie Longest]

Is your outside heat deflector angle flange at the top completely filled with sealant between the metal tip and body to direct the water off the top? The stainless outer plate is held on by the six pop rivets. (Most of your sealant is applied behind this plate.) The rivets also holds the intake exhaust flange and tubes in place The furnace and intake tubes on the furnace just slide into the wall flange tubes. If you shoot water directly into the two big holes they will leak. Look at the Suburban NT 16 SE(Q) inst. manual to see a drawing of things.
Eddie

[WDavidG]

Originally Posted by Eddie Longest

Is your outside heat deflector angle flange at the top completely filled with sealant between the metal tip and body to direct the water off the top? The stainless outer plate is held on by the six pop rivets. (Most of your sealant is applied behind this plate.) The rivets also holds the intake exhaust flange and tubes in place The furnace and intake tubes on the furnace just slide into the wall flange tubes. If you shoot water directly into the two big holes they will leak. Look at the Suburban NT 16 SE(Q) inst. manual to see a drawing of things.
Eddie

Eddie,
Thanks. The drawing in the manual is very helpful - I should have thought of looking there. Looks like a project to pull things apart to get to the rivets but at least now I know what things look like in there. Yes, the caulk does fill the gap behind the flange and looks like a good seal. As part of my experimentation, I taped over the furnace openings to keep any water from entering them, ran water down over the cover plate top and sides and my wife stationed in the scamp could see a film of water entering in the problem spots.

[WDavidG]

So thanks to Eddie for suggesting that I do the obvious (read the directions) without making me feel stupid, and Donna and others for their posts on other threads about silicone avoidance and how to apply pro-flex (I can't remember who posted the tip about dipping a finger in soapy water to smooth it - brilliant, thank you), I've successfully completed the fix for my leaky furnace vent.

I've had the scamp long enough to have fixed a few leaky rivets but still approach drilling out a bad rivet with a bit of trepidation. The Suburban drawing of the internals of the vent and their connection to the furnace helped but until I drilled the rivets and pulled the cover I wasn't entirely certain what I would find. The lower vent is a loose fit and short tube and easy to remove as I pulled the vent cover out after drilling the rivets. The upper tube however is much longer and a tight fit. I was tight enough I was concerned about whether I could reinstall properly but fortunately it was long enough I could pull the vent far enough out to work on removing the old caulking without disconnecting the upper vent tube.

The cleaning of the old silicone caulk (from the scamp factory) was the major challenge. I spent several hours with wd-40, mineral spirits, goo gone, fingernails and a plastic razor scraper trying to get it all off.

After a final cleaning with alcohol I used butyl tape under the vent cover and after re-riveting with #66 rivets I used proflex to caulk the edges. Interesting that the Suburban instructions for installing the vent cover note that the edges of vent cover should be caulked and stress the critical importance of also installing a bead of caulk across the middle, between the two vent ports. Apparently the scamp factory does not read this part of the manufacturer's instructions as mine had no middle caulk.

Except for the nasty job of removing the old silicone it was an easy fix. Here are a few pics (sorry - orientation is correct on my computer, but they seem to get rotated when uploading) that may help others who encounter a similar vent leak issue. #1 vent cover pulled out showing both vent tubes; #2 lower tube after removal; #3 vent pulled far enough for working on silicone removal but upper tube still connected.