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Porsche 944 Rain Water Leaks

Porsche 944 Rain Water Leaks - Complete List of Locations

I bought my 1988 Porsche 944S in 2016 and after what I thought was my dream car, slowly began a tough lesson in classic car ownership. This was not a chore however, more a challenge and so fixing these issues would put a great car back on the road for me to enjoy.



My passion for classic Porsche's led me to create my vintage Porsche apparel shop Retro Outlaws. Feel free to check out my Porsche 944 designs including T-Shirts, Hoodies, Mugs, and Hats.  

Porsche 944 T-Shirt


Problems and fixes for the Porsche 944

There are many useful threads online listing problems and fixes for the Porsche 944, 944 Turbo (951) and 944S2, but I found information was spread all over different websites. I wanted to create a solution to this by putting all the info  - or as much as possible in one place. So over the next few months I'll be releasing a list of possible issues to help others. I hope fellow 944 owners benefit by reading this, please feel free to share your problems and fixes as well.  

I should say I'm not a trained mechanic, so this information is for educational purposes only. 

One of the first issues were the dreaded rain water leaks! 

After the first downpour I noticed I had damp carpets in the drivers and rear foot wells. Plus dampness under the rear seats. After many hours, days, and weeks later I have finally cleared up (most!) of these issues.

What you'll need: 

  • Set of basic tools
  • Black Polyurethane Sealant 
  • A lot of patience
  • Odorless Smoke bomb/smoke machine  
  • Plenty of Tea and Coffee - try my Retro Outlaws Porsche 944 Mug

 Porsche 944 Coffee Mug

1) The first method for ascertaining your car's waterproofing is to let off an odorless smoke bomb. I used an odorless smoke bomb for fire alarms, but I would guess a smoke machine would work too so long as you seal the car off. I removed the rear carpet and placed the bomb in a container and let it off, shutting the rear hatch afterwards. The smoke will escape from places that aren't air/water tight. For example smoke escaped from my rear hatch straight away. This gives you a good guide on obvious places to look and fix. 

2) Wet Rear Carpet - I had wet rear carpets as a result of water draining from the fusebox drainage channel and entering the seams of the passenger wing. Water was traveling through the car - this was causing the rear carpets to get wet.

To get to the drainage channel under the Fusebox, you need to remove the wheel and the plastic wheel arch. You will need a Philips and flat blade driver to remove the plastic screws. The wheel arch is pliable but be gentle as you don't want to break this. Next, use water-proof Polyurethane Sealant and run it all the way up and down the crevice where the panels join - below where the water drains.

3) Check around the Porsche Fusebox - water comes in off the windscreen and floods this area. I had a hairline crack on the sealant around the fusebox causing water to run inside the car to the passenger foot well. Re-seal this area. See point 4) as these two are linked.

4) If you are getting wet patches in the front passenger foot well then try removing the glove-box and the black plastic housing which sits underneath the fusebox. You'll need a helper with a hose running water into the fusebox area. I then used a torch and laid in the passenger foot well looking for any water to come through from above. It was easy to see where the drips were coming from. Also, I unscrewed the fusebox tray and pushed this up far as possible. From here I could also feel the water around this area. So this needs to be re-sealed. 

5) The next leak was on the opposite side of the car to the fusebox. Check the welds in this area as I found two panels had a join problem. The welding had come apart. Again I used water-proof polyurethane sealant here.

6) Sunroof Drainage Channels - there are four drainage channels on each corner of the 944 sunroof - these can block up with debris and split apart joins inside the car causing water to leak. Use a guitar string or something similar like this to push down with warm water. You don't want to be too aggressive here, otherwise you'll separate the joins. 

7) Sunroof seals - these rubber seals can fail through age and crack. So if they are old, then these are worth changing.  

8) Poor alarm installation - I've seen poorly installed after-market alarms cause leaks. If it is attached to a bracket, check the screw holes. Make sure everything is water tight. 

It is worth checking where the cables go from the alarm, have they been sealed correctly so no water can go through? With age and heat, or even the wrong sealant, this can cause problems. I would clean these areas and re-seal with water-proof polyurethane sealant.

9) Rear Hatch Pin Drains - the rear spoiler has a drainage channel on either side. These can become blocked, just poke something like a guitar string through or similar width and use a hose pipe to clear these.  

10) I have heard of leaks behind the front wings, in which case they need removing to ascertain if you have a leak here. Depending on how competent you are, will determine if you want to have a go at this. I haven't done this so would advise caution. I would try to fix your leak problem before going down this route. 

11) Rear Light Units - Water can leak around the rear lens clusters into the bulbs/the spare tyre area/and wheel wells.  I must have had a gallon of water in the rear right wheel well! This is due to the rear light lens sealant failing. So remove these, clean the lens and body and replace with new sealant. 

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12) Rear Hatch Seal - I made the mistake of buying a generic 944 hatch seal and this not only caused a water leak, it also caused fumes to creep into the car. This was one length that you cut and join together.

I then ordered a proper seal which had no joins in it and this solved the problem. You will need to pop the boot pistons off with the help of a screwdriver. You will need to disconnect the rear wiper cable and unfortunately you can't do this at the window.

  • There is a plug connection behind the panel next to the battery, unplug this cable.
  • Attach a strand of electrical cable to this using electrical tape.
  • Pull the window cable through the top hole with the strand.
  • Disconnect these leaving the strand hanging.
  • Run the new rubber hatch seal round the hatch.
  • Then re-attach the window cable to the electrical strand and pull back into the car - reconnecting the plug. 

13) Rear Quarter Windows - These looked fine, but upon research I have heard that they can leak, presumably under the rear seats which is exactly where I have had water. Another place to check then! The fix is to carefully try and insert sealant between the rubber and glass. Peel the rubber pack with a flat edged tool and try to insert waterproof sealant. If this is too tricky then a window specialist may be advisable. Good luck! 

If you guys have any more suggestions please do share them!  

All the best guys till the next one, 





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