Why I Dislike Sunroofs (Part II)
Last week, I fixed the stuck-and-leaking sunroof in my rebuilt salvage BMW “FrankenThirty” by epoxying a broken section of the plastic lifting mechanism and installing generic closed-cell foam weatherstripping that seemed to fit perfectly. I also ran a stiff wire down the front two drains and blew them out with compressed air. The total cost was zero. I was insufferably pleased with myself.
In triumph, knowing that rain was predicted, and for a final pat-on-the-back-know-that-I-nailed-it test, I left the car in the driveway overnight. In the morning, I found water dripping from the headliner, puddles on the seats, and wet spots on the carpet.
So what went wrong?
Two things. And it got worse before it got better.
The first one was a dumb oversight on my part. In addition to the sliding sunroof panel, there’s the rectangular section of the headliner that attaches beneath it and slides along with it. To remove the sunroof, you need to detach the headliner panel and slide it back so you can access the bolts holding the sunroof to the track, then slide it forward when you’re done. I did that, but I hedged my bets and didn’t snap the headliner panel back in place. This left the rear part of it sitting behind the back of the sunroof panel. The water got past the seal (as it normally may), but instead of all of it dripping into the trays in the moat, the back edge dripped onto the headliner panel, and from there into the car. I’m virtually certain this is what happened, because when I slid the headliner panel forward, the whole thing was soaked.
The next thing involved me massively exacerbating an existing problem, but likely had nothing to do with any of the water.
As I said last week, every sliding metal sunroof installed in a car since the 1970s is surrounded by a tray that’s basically a four-sided moat with a drain spout at each of the corners with hoses attached to them. The front two drain hoses run down the A-pillars, the rear two out the C-pillars. These hoses may emerge through the corners of the wheel wells, or they may stop short and dump the water into the rockers and sills. Sometimes there are dedicated holes for the water to run out, sometimes the drain holes get clogged, and sometimes, as with the rear drains in sunroof-equipped BMW 2002s from the 1970s era, there are no drain holes, and water just sits and rots things out from the inside.
Since sections of the rug were wet, it seemed likely that there was a drainage issue, so I directly tested the four corner drain spouts by pouring water down each one. My driveway slopes slightly downward, so I tested the front ones first. Water poured down the right front immediately produced a stream from near the front of the rocker panel, but the left front drain only yielded a few drips. The front drain holes in an E30 are obvious, so I cleaned them out with a coat hanger and repeated the test, but no water came out of them, just a couple of drips a few inches further back.
I swung the car around in the driveway, angling it nose-up to test the rear drains. They’re far enough back that you can’t easily reach them to run a wire down them, but I could certainly pour water down the left and right moats so that it ran in their direction. I was surprised that the water came out from behind the plastic trim of the rear bumper, but a quick check online showed that that’s where the rear drains emerge.
So, back to the left front drain. I redid the test, this time pouring almost a quart of water down it. I crouched down in front of the car and could see that water was now dripping from beneath it, but it seemed to be coming more from the front of the floor pan than the rocker panel. I looked inside the car and was surprised to see the base of the accelerator pedal surrounded by water, and the driver’s side rug soaked. This was far more severe than the few wet spots on the rug I’d initially seen.
Well, crap.
My first thought went back to the leaky sunroof on my Nissan Armada. There, the cause was that the hose had detached from the right front corner of the sunroof drain, causing a fair amount of water to leak down that A-pillar. I did what I did on the Armada, which was to arthroscopically expose that corner of the sunroof by pulling down just enough of the headliner to see it. In doing so, I came face-to-face with a pretty good-sized mouse nest.
After the detour to deal with the nest, I looked at what I came to see, and found nothing wrong with the hose attachment at the left front corner.
I wanted to see for myself where the bottom of this hose was, so I removed the kick panel at the lower left corner of the driver’s footwell. The hose was right there, hanging down into the sill, though ending perhaps not as far down as I would’ve expected. I had one of my kids pour water into the drain while I verified that the water actually came out of the bottom of the hose. It did, but only barely. Instead, more water pooled around the accelerator. Why wasn’t it draining properly?
I took a coat hangar and poked it up through the drain holes at the bottom of the front fender. Despite reaching inside the sill (where the end of the hose was) with my hand and looking with a flashlight, I could not find the other end of the hanger. I began to wonder if the path between the two had been blocked by boodged-up bodywork that accompanied the resurrection of the FrankenThirty from its salvage-title status 32 years ago. I removed the plastic liner of the inner fender so I could see the other side of the drain holes and came to a startling conclusion:
My decades-long belief that these two clearly visible oblong holes at the base of each front fender are sunroof drain holes (and it’s not just me; they’re referred to as sunroof drain holes all over the web) is simply wrong. They are in fact not sunroof drain holes. They drain any water that makes it past the plastic fender liner.
So where the hell are the sunroof drain holes?
I had to dig surprisingly deep on an E30 forum to find the answer. They’re two small openings in the weld between the inner and outer sills (the rocker panel). One is near the door hinge, the other is about 2/3 of the way back. They’re not visible unless you jack up the car, stick your head under, and look outward. Even if you do, they’re not easy to see. They clog easily, and they can easily be mistakenly sealed up during bodywork by someone who doesn’t know they’re there.
The rear one was plainly visible. I poked the coat hanger up it, and water gushed out.
The front one, however, took me a while to find. It looked like someone had jacked up the car by the door sill (something I avoid doing), and the action had partially folded up the lower part of the outer rocker.
This one was also completely clogged up. I cleaned it out, put an extension on the rubber hose so it emptied just in front of it instead of several inches above it, tested it, and water flowed freely.
I never got to see the exact path by which the water I was pouring down the sunroof drain overflowed the non-draining sill and wound up on the floor, but it didn’t matter. There may have been some amount of water intrusion by this method during the years the car sat outside with a sunroof that was neither fully closed nor sealed, but it’s almost certain that the unnaturally large quantities of water I was pouring for testing purposes created its own problem—that is, I caused water to pool at the base of the accelerator pedal and soak the rug. The wet spots on the rug I saw after the car had sat outside overnight were almost certainly from water dripping from above due to the mispositioned headliner panel.
It’s certain to rain again. We’ll see whether I’ve nailed this one shut or not.
Still not a fan of sunroofs.
***
Rob’s latest book, The Best Of The Hack Mechanic™: 35 years of hacks, kluges, and assorted automotive mayhem, is available on Amazon here. His other seven books are available here on Amazon, or you can order personally inscribed copies from Rob’s website, www.robsiegel.com.
Several issues here. Service manuals are a great help on vehicle’s you need help with.
And again when you buy cheap old crusty vehicles you get all the past sins of owners that were neglecting of the cars care. Also that is the reason you got a good price.
Might avoid sun roofs on all but well cared cars. Hate the decision not the option.
Just imagine how smug you’ll get to be the next time sunroof drainage comes up Ina bmw enthusiast circle and you joyfully correct everyone there. (Just kidding, we know thats not your style, but you can always pretend.)
That last drain plug was very well hidden. Hopefully there isn’t too much rust in the parts you can’t see.
Geez; the PATIENCE.
At that point I probably would have taped over the sunroof’s exterior, maybe after a good caulking, and then given the car a kick as I walked away for a strong beverage.
🤣
It’s the challenge! He’s not going to be beaten by any stupid car.
I agree. I have ordered a couple of 911 and much to the chagrin of my sales guy, I ordered both without sunroofs despite being told it would affect the resale value. I still have a 911 and interestingly enough the guy I sold my first one to was specifically looking for one without a sunroof. I’m not a convertible fan either unless it is a hardtop that I’d only put down about twice annually.
I also don’t want a sunroof. It’s almost never sunroof open weather. It’s always too hot or too cold. Nothing worse that one that won’t close.
I open the sunroof a lot, but my wife really gets our money’s-worth: as long as the temperature is below about 90, but over 60, she has it opened. She grew up in a house without A/C, and no A/C-equipped cars, and she has never fully adopted A/C, it seems.
At least there is a solid enough floor to hold the water that bypassed the sill. Things could be much worse.
I’m a fan of sunroofs if their made of glass, I own a 1985 RX7 GSL-SE that I bought from the original owner back in 1994. It came with a removable sunroof and I was able to find and OEM glass panel. It has never leaked in the thirty years I’ve had it. My daily driver is a 2000 Acura RL with a retracting glass sunroof that I’ve owned for eighteen years and it doesn’t leak either. It’s nice on a 30 degree winter day when the sun is shinning to have the sunlight shine in. However, if you plan on cleaning out the drain tubes on a sunroof I would recommend using 12 gauge wire as opposed to using a coat hanger. The wire is stiff enough but will not damage a drain tube hose like a coat hanger may.
I too hate Sunroofs. To noisy to drive over 30mph when open, sun gets in your eyes when driving against it, lots of wind buffeting when open at any sort of speed and lets a lot of cold in through the glass in winter. I mostly drive with both the sunroof closed and the inner panel closed. If I want open air motoring I use my convertible. What really irks me is that I had to get the sunroof to get all of the other options that I really wanted on the car. Thanks Hyundai
The old “preferred option package”, or similar, strikes again.
I have had great luck with heavy duty weed whacker cord. Just flexible enough to work its way down, especially with twisting, but stiff enough to get all the way through without damaging anything.
Just as is a convertible, a sunroof is always worth the money – and USUALLY worth the trouble!
hey rob, i like your article’s 2nd to last line: ‘we’ll see whether I’ve nailed this one shut or not’. was this an intentional pun?
and although i don’t care for sunroofs either, or moonroofs for that matter, i like a challenge like yours. sorta like a 2000 pc puzzle with tiny pieces. and fixing the problem is a reward enjoyed most by using said repaired (and working) system.
a few years ago i bought a ’97 sentra ‘as is’ with lots of issues from a used car lot, foggy headlamps being one of them. before getting around to polishing the lenses, i found a pair of taiwanese knockoffs with clear lenses in a local picapart for cheap. one of them had a moulded-on-housing adjuster bracket broken off. i custom fit some plastic pieces and adhered them with plastic weld type glue. after installing them, one drive at night showed i didn’t need to make further adjustments. hopefully you’ll get the same feeling i got here when your fix passes a rain test.
I just had my Buick at the dealer to fix my leaking sunroof. Same symptons as the author’s. My issue, according to the service guy was because of leaves getting in the fender well. I wasn’t going to take issue with him on how leaves got in there but I’ll bet a case of 20/50W for my TR6 that it was mice and their pension to build nests. I began using Loraffe electronic mice repellent for all of our cars a couple of years ago. They seem to work. Too bad I waited so long to put one in the Buick.
I’ e had two cars with sunroofs, and neither one was worth the trouble.
My first new car was a 72 Capri that was fairly well loaded, including the sunroof. One of the plasic pieces that connected the threaded cable to the sunroof broke, and was not replaceable. I eventually got it closed and left it that way.
I still have an 06 Subaru Forester. I believe the sunroof (glass power operated panel with a manual sliding headliner) was standard – I took the car from dealer’s inventory. After a couple of years, the glass panel wouldn’t raise up to seal the opening, and it leaked until one time I was finally able to get it closed. I’m pretty sure I haven’t opened it in ten years.
Clearly, I can do without them.
Yikes, forget the leaks. You have purchased a rats nest of a BMW. You need to absolutely disassemble the interior completely and carefully and remove any more nests. You have no idea how bad these nests can be to your health. That car has to take on a really bad odor when it becomes damp outside. Make sure to wear a mask and gloves and remove your clothes before going indoors or purchase a disposable full body painters outfit. Have you looked under the seats? In the doors, quarter panels, the rest of the roof under the headliner? You most likely have nests hidden everywhere. Do NOT use a vacuum or use compressed air to blow at them.
Seriously, clean and disinfect that car asap. Rats and their nests can spread Hantavirus Cardiopulmonary Syndrome. Not a joke. https://www.mayoclinic.org/diseases-conditions/hantavirus-pulmonary-syndrome/symptoms-causes/syc-20351838 Use bleach on any nests and once the bleach has soaked the nest thoroughly, double bag the nest and place it (them) in the trash. Having purchased this car on a rainy day, I cannot imagine how you missed the terrible odor, especially with the front fresh air vents loaded with nests plus being rained on. Regardless, disinfect that car before driving it.
As Mayo Clinic notes…”Because treatment options are limited, the best protection against hantavirus pulmonary syndrome is to avoid contact with rodents and safely clean up rodent habitats.”
Great reminder of a serious hazard lurking in old vehicles! Thank you.
My “special” car is a 2007 VW EOS (red, standard). But convertibles are terribly windy at speed, and from the back. Plus periodically they fail to go back up… too many switches in the logic. I drop all the windows and open the sunroof every time I drive it. Perfect. And no problems. I had leaks at the A-pillar drain lines. VW in their wisdom put a smaller line into a bigger line thus in rain the connection leaks. Cure… never park downhill. Driving in heavy rain is not a problem… rear drains do the job.
Aftermarket units may be the ticket. I had a ‘54 Olds Holiday Coupe, sunroof was a manual unit installed by a moonlighting Harrah’s collection restorer. Never a drop inside.