Lets clean those drains....

From an older post (slightly edited) I made on another (unnamed) Porsche forum: Why is cleaning the drains important? Because Porsche mounted expensive electronic modules right on the passenger compartment floor - where flooding will damage them, and likely the connectors from the wiring harness to them. Repairs in the multi-thousand dollar range are not uncommon. Due to its nature - the soft-top of the Boxster makes this more common - and there are multiple drains involved specifically for the soft-top. But - the Cayman isn't immune. It shares the same drains in the cowl area that the Boxster has and they're equally susceptible to plugging up and causing flooding. It's particularly likely this time of year as the leaves start falling. So below are two diagrams and two number guides. You might want to print them out and toss the one that applies in your glovebox, or car documentation. BOXSTER: CAYMAN: There are lots of techniques discussed in other posts about tools and techniques used. The under-hood cowl drains are accessible by removing the beauty panel over the battery and the two cowl end panels. Cleaning the area of leaves is helpful, and many people find it helpful to simply remove the rubber one-way drains that Porsche uses in the cowl drain holes. The rubber drains tend to clog up with debris, especially leaves and whirligigs (oak tree seeds). Removing them gives a better chance of the debris passing through without clogging. A good cleaning of the area is helpful, and you don't have to remove the battery to clean this area. The other drains - Boxster and Cayman are toward the car's rear, and in the Boxster in the top compartment. There are more there than most people know of - some are rather subtle - a drain that runs right through the rubber trim the top seals to is seemingly unknown by most owners. Compressed air is good to clean these, provided you don't use too much pressure (which may blow the drains apart at a joint). The Boxster top drains are easier to see with the rear wheel-well liners removed. You can see the output and by pouring water into the drain from the top, confirm that they're open. There are two drains in the top compartment, visible if the top is partly opened (clamshell up and rear of top lifted). These go into the rubber membrane that lines this compartment and may have to be looked for. Once you find them - they're pretty obvious. Porsche sells a screen for these drains that keep it from clogging if something like a leaf lands on top of it - before having the screen this was very likely to happen since the water going to and down the drain would carry debris and leaves right to the drain. The screen sticks up about 1/2" - and effectively stops that from happening. A cleaning tool I've seen mentioned but I haven't tried (I might for my Cayenne drains - same problems) - is a trombone (or bore) brush: You can find these easily, and probably even locally by just Googling it. Amazon of course has a bunch of them. For the moment I'll sticky this thread - and hopefully, members will have some input for it. If we ever get a dedicated 987 DIY forum - it will be copied there. (Here on Planet-9 we've had a dedicated 987 DIY forum forever.. not like that inferior Porsche forum..)

Brilliant, Don. FWIW, I use both compressed air and the trombone brush with good results. Running water as a a controlled test is key.

Oh, I didn't know about those drains in 5 and 7!

Can confirm: clogged drains can lead to expensive repairs when the electronics get wet. :-( Are the drains supposed to have obvious exits under the car? I sure don't see any. When I test my drains with a garden hose, the water seems to seep out from various unseen cracks and gaps, not from any clearly defined drain holes. I guess that's okay -- as long as all the water comes out it's okay, right? -- but it wasn't what I was expecting to see.

None of the drain outlets are really obvious. The ones for the top storage compartment come out behind the rear wheel liner. If you take out the wheel liner you'll see them. The front cowl ones dump into the fender recesses somewhere.

Having been the victim of malfunctioning drain holes that resulted in thousands of dollars of repair bills I explicitly request that the drain holes are examined, cleaned and tested when its annual service is undertaken. No, it's not covered by warranty despite a rather obvious design flaw which has gone uncorrected across many models, including 911 cabrios, for many years (decades). I was told by my Service Manager in an ill-advised attempt to placate me (it didn't) that Porsche SUVs are also prone to serious water leaks in heavy downpours, not just the sports cars.

Hey everyone! Springtime is coming (for those of us in the northern hemisphere - didn't mean to dis-include anyone!), so I wanted to post-bump this because people forget to check their drains too often (and new owners may not remember to do this!) It's an easy task, but be sure to check and clean as necessary!

A quick question. Under the clam panel (ie the panel above the rear trunk and below the roof), there are two drainage holes. If the lining around these are punctured, obviously it will need replacing, but will this leak into the cabin, or to the ground below? Hopefully most of the water will go down the drainage holes.

Can you also tell me, there are four drain holes around the battery under the frunk. Is it normal for my trombone cleaner to only go about 8in down in each of these before bottoming out? I suspect there is bend or something I can't seem to get past? Same on all four holes.

To both questions: Post #1 - it's entirely possible your linings have been damaged given the amount of damage that's occurred with the top mechanism (things breaking and flailing around.) If it were me - I'd replace them. If holes in them resulted in water just going to the ground - why bother having them? They're there for a reason. I do recall one chap replacing his, I assume for something similar, and it wasn't difficult with the top assembly removed. I imagine you might also try repairing tears in them if the tears aren't too awful. Tire patches should work.. all of this work will more easily be done when the top mechanism is removed from the car. At that point the rubber liners should be easy to access. OK - post #2 - those drains just leak down in the dead space ahead of the firewall. I believe you're hitting the shell of one of the wheel arches when you feel it bottoming out. You can check if it's open by simply pouring some water into it and seeing if it comes out. I'll mention again - most people end up removing or modifying those rubber drain things. I think they are designed to keep air from flowing back into the battery compartment - which I don't see as a problem. Or to keep rodents out.

Don’t forget the ones under each door

Umm.. which ones under each door? The door drains? They usually aren't a problem. If they plug up you'll see water slowly dribbling out on the door sill, maybe overnight sort of thing. Then it's time to clean them.

Apart from the well-known electronic module under the left seat, are there any other electronics at risk if the drains aren't all cleared? To ask it another way, if it's pouring down rain and my passenger footwell stays dry, am I safe?

You might feel around under the starboard seat too. On the .2 series any factory auxiliary amplifier (ASK, Bose) lives there (except the subwoofer ones that live in their housings.) I'm sure Porsche wouldn't let that space go to waste..

I’m having a hard time understanding where the drain lines aft of the drivers seat are on a cayman . I found the frunk ones today, but not sure about the others. Also, it isn’t clear to me how any of these would drain into electronics on a cayman . Is this really an issue for the tin tops?

Same. Anybody have a picture of #4 on the Cayman diagram? I'm not finding them under the carpet.