Water dripping from bad seal on front cap

[mark.g]

We have been getting a lot of rain lately, after the last wave of rain I noticed water dripping from the roadside corner of the front cap. Upon investigating I discovered that there was a bad seal where the molding from the front cap wraps down underneath the cap on the roadside of the RV. I found some additional bad caulk seals towards the top, used some Sikaflex-221 at the recommendation of a nearby RV/trailer dealer.

I tilted the whole RV to the front/roadside to get the rest of the accumilated water out and did not see anymore leaking....Until it rained again. There is still water accumilating behind the front cap but I am unsure where it is coming from. The rest of the seals look good. I called the dealer and they are trying to get me to bring it back in for them to look at it. They are not particularly close, so I prefer to do what I can before taking it to the dealer. My hesitation at this point is the dealer cannot or will not tell me what they will do to find and fix the leak, which does not give me much confidence in their abilities.

What can I do to help find this leak and get it taken care of? Where could the water be getting in? After I get it fixed, what can I do to ensure I do not get mold from moisture left behind? Thanks!

P.S.: I have not resealed the bad seal point where the water is draining from to ensure that I can continue to drain water until the source of the leak is fixed.

[Karl4Cat]

The molding strip that covers the point where the front cap meets the fiberglass siding and roofing material runs all the way around the RV. I also had water tracking down mine and dripping under the nose by the pinbox. I found that there were some voids in the Dicor sealant on the roof where the screws went through the channel molding. I put a dab of Dicor on each screw head which cured my issue. I also had a void in the Dicor on the ODS giving me a leak onto my bedroom nightstand that I fixed at the same time. The problem is not so much the manufacturer's application of the sealant but rather that is contracts as it cures. Dicor cures VERY slowly so a void may take some time to show up. Mine were caused by small air bubbles in the bead. They could 't been seen when it was being applied or even when I picked it up but as it slow cured over time and shrunk a bit, the air bubbles opened up creating the void in the sealant. A couple months after every RV is manufactured, the roof should be gone over to re-seal any voids. They won't always be there but if they are, this is when they will show up. It's easy to blame the manufacturer but in their defense, you can't fix what you can't see.

[mark.g]

The dicor up top is good. I think I nailed down the last water entry point to the roadside front marker light. It has a clear sealant around it but it there is a section on top that has been compromised. Is this just clear silicon caulking or something else?

[Karl4Cat]

I thought it was silicone when I had to replace my two front markers but it's actually Geocel 2300 MHRV vehicle body sealant. That said, I wouldn't go out and try to find it if you just need a small dab. Silicone would work just fine. It did on mine anyways...

[Mr Havercamp]

Originally Posted by mark.g

The dicor up top is good. I think I nailed down the last water entry point to the roadside front marker light. It has a clear sealant around it but it there is a section on top that has been compromised. Is this just clear silicon caulking or something else?

That's a common issue and not only with F.R. products. The caulking around the light is just the first line of defense. The main seal is supposed to be butyl tape under the light. Now days it tends to get skipped either by intent or just missed. You can get more water in one of those lights than you think, especially on a front curl of other sloped surface.

Even when they are sealed correctly, water can sometimes get past the lense on the cheap fixtures and chase the wiring through the body of the light itself.

A lot of manufacturers are going to silicon sealants, the only way you can be sure what they used is ask them. If it is silicone it will be "neutral cure" and not "acetic cure". Acetic cure is what you find at the big box or ace hardware that smells like vinegar, you don't want to use that. Neutral cure is the s$#t.......It can only be found at commercial supply houses, glazing supply, online, etc.

[Karl4Cat]

I have a tube of what they use from my trip to the plant. As I posted, it's Geocel 2300 MHRV vehicle body sealant. Drys solid unlike silicone. They use this all over the exterior where light are installed and where the molding is used to cover seams. Have soap and water on your hands and your tools when shaping the bead or you'll be wearing it for a while...

[WolfWhistle]

It's quite the sealant, K4C.. The factory slopped it here and there. But when they got where it should be, it looks like a heck of a product. I think a product would be better if it didn't harden. Silicon makes such a mess.
WW

[VinceU]

Best test is a centrifugal blower like the flood recovery people use for carpet and floor salvage. Set on roof and connect with vinyl chute to an open vent and tape together. Shortly after test all suspect areas with spray soap.