Hey everybody, I'm new to Toyota, but I've been working on German cars for quite a few years. Considering our 2011 Sienna has been extremely reliable, I was surprised when water began to get inside during heavy rain. It started with water around the front sunroof and front visors during a nasty thunderstorm. I extensively tested the sunroof drains and found no issues. Next the seatbelts would get wet during heavy rain, and again the source of water was not apparent. I knew SOMETHING above the headliner was leaking, but didn't want to remove the headliner and all of the pillars to find it. Eventually water was pouring into the back luggage compartment, and I had to tear into it. Upon removing some trim from the back and looking with a flashlight, I could see the shark fin antenna was dripping water inside the headliner. I also became suspicious of the roof rack, since the mounts are very similar. I gently pulled the headliner down near the B-pillar, and looked above to find that the roof-rack mounts were indeed leaking.
HERE'S THE FIX!
It takes about 2 hours and requires fairly basic tools. This should apply to all 3rd Generation (2010+) and possibly older models too. The seals on the roof rack and shark fin antenna are woefully inadequate.
1. Gently remove the covers at the front and back of each roof rail. A plastic trim tool works great, just start at the rounded end and pry up as you work your way around the cover and remove it. Under each of the 4 covers you will find 2 T-30 torx bolts, remove the bolts, and pull the roof rack off the car.
2. Clean EVERYTHING. I used Lysol wipes to remove the gunk, and isopropyl alcohol to prep for silicone sealant.
3. Apply silicone sealant around each of the 3 holes for each corner of the roof rack. I used Permatex Ultra Grey and applied it generously.
4. Reinstall the roof rack, and give sealant some time to dry.
Now for the shark fin antenna!
1. Open the rear hatch, and remove the top center trim piece at the rear of the roof. Be mindful of the wires as you pull down, it is only attached with plastic push-connectors, so it pops right off. A trim tool is recommended.
2. Remove the seat belts from the rear pillars. Just lift the cover and remove one 14mm bolt.
3. Gently pull the pillar loose at the top to give clearance to the headliner.
4. Gently pull down at thew rear of the headliner, and you will see that the shark fin antenna is above a black plastic HVAC duct. Pop loose a few of the trim connectors holding it to the roof to give yourself room to reach the shark fin connector.
5. Using a 22mm wrench (or adjustable), loosen the collar on the shark fin, and wiggle it free from the top of the car.
6. Clean and silicone the shark fin, remount it to the car, and reverse disassembly instructions.
