I originally had to unclog my 2005 S-Type's moonroof drain hoses back in September 2012. My right rear drain hose is the one that tends to clog, and after last week's heavy rainstorm I noticed a bit of water underneath the right rear carpet. So I knew it was time to bite the bullet and blow those drain hoses out again. I spent quite a bit of time today removing all necessary interior trim and pulling both sides of the headliner down far enough to be able to reach all four drain hoses on the moonroof pan. I pulled all four hose ends from their respective nozzles on the bottom of the moonroof pan, then drove over to the trusty Snappy Lube about five miles away (they perform all of our required annual vehicle inspections) to borrow their air hose for the big drain hose blow-out. Just as it was in September 2012, the right rear drain hose was the culprit and quite a bit of congealed pollen and who-knows-what-else was blasted out of there after a couple of quick bursts of compressed air. The other three drain hoses were relatively clear....

Putting everything back together was more of a challenge this time because the car is now 12 years old and the foam backing underneath the headliner fabric is beginning to break down as all Jaguar headliner foam backings tend to do. I used contact cement around the edges to bond the fabric back to the headliner surface and while it certainly is not perfect, it turned out better than I thought it would. I truly do not want to go through the hassle and expense of having to remove the old headliner fabric, clean up the headliner frame, and install new fabric. I would much prefer to leave that task to the next owner. We'll see....

 

Pardon my ignorance. I did not know there were any drain hoses up there at all, but now that I know, I would assume they drain to a place under the car. Why the need to take the headliner out at all? Would simply blowing air not blow the junk out the intended destination?

 

If you attempt to reverse-blow the moonroof drain hoses by inserting your air hose nozzle into the bottom drain hose end underneath the car, then you are likely to cause the top drain hose end to blow off of its nozzle on the bottom of the moonroof pan. You would then have to drop the headliner for two reasons: First, to reattach the drain hose end to its nozzle. And second, to clean up the mess you just made by blowing all of the clogged water and debris into the area underneath the moonroof pan and above the headliner. That would be a disaster....

 

Great work, Jon.
I suppose if one was stuck in a week-long rainstorm and couldn't get the car under cover, and further didn't have the fortitude/skill/ambition to drop the headliner and clear the hoses with a blast of compressed air.....it MAY be possible to run a small wire up the hoses from the exit-end and clear the clog, temporarily.

The trick would be in finding a wire stiff enough to penetrate the gunk yet flexible enough to follow the contour of the hose ID. Probably ultimately more work than doing it properly through the headliner, as you'd have to work the wire in small reciprocating movements while twisting.

 

Zane,

Given the length of the moonroof drain hoses and the twists and turns they make along their respective routes, it would be very difficult to unclog the drain hoses via the Roto-Rooter snake method. And you would be pushing the debris up the hose towards the moonroof pan instead of down the hose to the ground. While I hate having to drop the headliner to perform this job, I believe it remains the most effective method of clearing the hoses of all clogged residue....

 

If anybody wants to try the cable method, I am thinking that a cable from a bicycle would work well. Get one that has a head only on one end and the other end will be welded closed to keep it from fraying as you push it through. A mountain bike brake cable is 1.6 mm and derailleur cables come in 1.1 and 1.2 mm options. I work in the bike businesses.

 

Maybe a plastic strimmer line? Not sure it will be stiff enough though.

 

First time for me, yesterday on the 05. Strangely enough, the 03 hasn't needed it yet, it appears, although the 03 parts-car could do with a drain-cleaning. I started on the left side, then did the right, front-to-back, both sides, didn't encounter an issue until the last one in the right rear. Absolute clog. 100 psi air hose and all I got for my trouble was a face-full of blowback! My first thought was to grab a handy small worm-gear clamp from the pegboard and clamp the hose to the air nozzle and have another go. Turns out my tiny worm gear clamps weren't quite so handy. I know i have some....somewhere!

I had some control-cables of unknown origin...I believe I obtained them in a box of quite useful stuff a friend gave me when his wife was "cleaning" his garage..."helping" him by throwing out a bunch of useful stuff. Anyway, I actually COULD find those, even so I've no notion of their origin nor foresee any particular use for them. Not thinking far enough ahead that housing and all were small enough to run down the hose, I cut the crimped end off the wire to extract it from housing, re-bent it to prevent poking a hole in the hose and ran that in its full length a few times. Re-tried the air hose - no joy.
Tried the control wire housing - similar result.

Then it dawned on me: Spruce Bruce (long-term down X300) in the adjacent bay was just bristling with the sort of worm-gear clamps I needed. I removed one, cinched it down tight around the hose and air nozzle, pulled the trigger....and....POP!!! then the free flow of air exiting somewhere 'round the lower rear of the car.

I then recruited my 16 yr old daughter to attend to the air trigger while I searched out the exit point. My concern was that I'd blown a hole in the hose somewhere in the boot.
Never found the exit, per-se - the other end of that hose is well-concealed. I did find a length of the hose routed through a bulkhead in the boot, passing outboard into the fenderwell and pinched it off with my fingers to confirm there were no leaks upstream of that point. Finally, I removed the air nozzle and fit a funnel and poured water in the hose. It came dripping off the muffler and formed a puddle under the right rear, aft of the right rear tire. I called it good. Here are some random pics in case they be of help to someone.

Needs a headliner.....maybe this spring/summer when everything else is brought into fine nick...

 

Good job both of you.

 

In the ongoing saga of clogged lines, I discovered, after an uncharacteristic drought in FL, in our 1st deluge of the season, that my roof leaks at the manual opening plug. Would that also be from clogged lines?

 

You will need to test the moonroof drains by opening the moonroof, finding the drain entrances on all four corners, and pouring a few ounces of water into each one individually. If your poured water does not show up on the ground within a few seconds, then you have found your problem....