Arch's Leak Pictures
Find the source of leaks in the GMC motorhome can be a time-consuming and frustrating task. Arch provides these pictures.
The round vents on top of the GMC are a common source of water leaks. Here are the results of aleak from a vent. You can see the water stains as dark brown or black. The dark streaks are a good indicator of a past leak. Finding it can be difficult. Here in the case of a vent, it's pretty easy to tell the source - after you have the headliner out - and a storage locker down. But sometimes water will run along the ceiling members and become visible far from the source.
Other outside cuts in the body are potential sources of leaks. Here thewater fill shows the signs of leaks. To check this area you have to remove various components - especially the cosmetic cover that is on the driver's side rear. You may find that the cover looks fantastic form the outside, but has been damaged by water. Mine was too damaged to put back in place.
The drip rails have been a source of many leaks. Age and corrosion take their toll. Arch could not get his rails off to check for a rear leak, but he could get theinterior cap off. He was able to see a significant hole through to the rail from inside the coach.
One other leak that happens - the fresh water tank. Age and abuse takes their toll on these items. Because the tank sits on a wooden floor and is out of sight, there is the potential for significant damage happening completely out of sight. Here Arch hastreated his new rear floor "The last thing I did was to seal the flood to give it a little bit of protection. I first put down a coat of polyurethane varnish thinned with 25% mineral sprits then a second coat of 100% poly. Make sure you have time for this to dry. First coat took several days to dry----but it was fall."
To see more about replacing rotten patches in the GMC floor, check out my chronicleof rebuilding the rear bed.