Leaky antenna on roof

Mike Barber · March 10, 2017

I just got back from having the high frequency antenna (shark fin) replaced on the roof of my 2016 2500HD Chevy. The tech said they replaced the old one with a new one that is the same part as the old. He said the way they snap in they can't be reused once they are removed.

While waiting at the window I saw a service sheet for another truck which said that poor guy was getting at least his second fix for a leak.

So, my question is - how many times can this be expected to happen? My goodness, it cannot be that difficult to seal up a hole if the roof. What have others ran into with this problem?

He said the headliner was fine and only needed drying out. There is no visible sign at all of there ever being a problem so I am OK with that, but I sure don't want to do it again.

Thanks!

O_J_Simpson · March 10, 2017

Until GM redesigns the seals it is a crap shoot with shark fin antennas and 3rd tail lights. All I can say is good luck getting a seal this time.

Dungar · March 11, 2017

I've had mine replaced twice in the last 8 months 2016 HD

Rvduck · March 11, 2017

So far mine has been fine but as a preventive measure I am going to mask mine and put a neat bead of clear silicone around it. I had to do that on after marker clearance lights on my 08 Silverado.

MotionMan · March 12, 2017

Maybe you are filling it too high, try to put a little less Antenna Fluid in it so there is room to expand when it gets warm. . Try Flex Seal, it can keep a boat with a screen bottom afloat, it should keep water out of a small hole in the roof, just dip the whole truck in it.

Peterd · March 12, 2017

Is common First sign of a leak was a tell tale streak coming from the base casket. Must have been antenna fluid!! Replaced with GM parts and have been OK the last two years. No streak so the fluids must be at the correct levels. Now if I could only get volume normalized...

Mike Barber · March 13, 2017

Thanks for the replies. It doesn't sound too encouraging but maybe I'll be one of the lucky ones. How long before the third brake light starts leaking?

I guess it's a little much to expect a $50k truck not to leak. Maybe I should keep it in the garage and park the convertible out in the rain.

What a shame. Except for this one problem I really like this truck. I am confident it can be fixed if it isn't already.

Thanks again.

MotionMan · March 14, 2017

Yeah, it can be fixed. I would try and make friends with the tech doing the work so they know you and will give it a little extra. I always sneak in and talk with them, it goes a long way. Plus you can usually find an engine or transmission out and apart and I quickly diagnose the problem and put them back together. that goes a long way too....I know the cover is tricky or I would say give it a try, that and those pesky headliners, one wrong move and it's crease or tear. Hopefully that doesn't have to come down but in any case this has to be removed completely, inspected, sanded, painted and new hardware and gaskets. If there is water there is corrosion and it has to be removed and sealed. If you don't have them this is a good time to install Cab Lights

Doug Rosewood · March 14, 2017

I had the leaky fin, my dealer replaced with new fin and "took care of it" aka sealed it under the fin..been two months now of rain/snow sloppy weather and so far so good.

eviltwin69 · March 18, 2017

I just had mine done this week. So far so good with quite a bit of rain the last couple of days. Hope it works. For the money we pay for these trucks you would think they would be able to find a way to seal them right the first time.

Mike Barber · March 18, 2017

Storming and blowing here too, and the inside is still dry with the week old antenna.

Donstar · January 24, 2018

I found out yesterday that I have a Shark Finn leak. It can be a less than obvious problem so I am bringing this post up again to remind new members to be aware. Mine showed up as water drops on the parking brake pedal. We recently had a few dry days and this caught may attention. I then noticed a couple of drips coming from behind the dashboard after a heavy rain. I had suspected something was amiss because it has not been dry under my floor-mat lately. I can easily see where this can go undetected for a long period of time so make sure you watch for this before your warranty expires!

Buckshot556 · January 25, 2018

If you look at the fin, atleast on my 16, you'll see that there is a gap in the upper area of the gasket. I think this is a breather hole. Why GM flunky engineers didn't put this hole on the bottom to act as a drain/breather I will never understand.

i blew compressed air into the hole while gently tugging up on the fin and water ran out down the windshield. After it was dry I put some silicone into the hole to close it but not 100% confident this will never be an issue for me.

Also, here's a great idea for the dinguses at GM....have the third brake light inside of the cab against the back glass like they do on a lot of cars. This way no leaks!

GMC4Zee · January 26, 2018

Put me on the list as having a leak. The dealer replaced mine back in december and i see no sign of new leaks. But I did not see water prior but just mentioned it was loose on my last service and they addressed it. They said the under side of the headliner was water stained but no other issues(meaning rust).

joet6890 · February 2, 2018

#me too. Whups, wrong forum.

Yeah, I got rained on in early December while driving. At first I'm like, "What the... Where is this coming from?" I noticed it was coming from the visor swivel point.

Dealer knew right away it was the fin gasket. Apparently the fin needs need to be color matched to the truck. Took about 5 days for it to come in.