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Replacing Water (Coolant) Guide Housing '05 Boxster S- Help!

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At first I thought the water pump was leaking, but with careful examination, discovered the plastic "Water Guide Housing" (P/N 987-106-508-04) used to route coolant from the front of the engine to the front radiators, sprung a rather large leak at the mold seam on the bottom of the part near where it makes a 90 degree bend and joins the "Henn" fitting on the large rubber hose. I removed the 9 screws attaching the housing to the engine, and have a new replacement part, but can't figure out how to get it out, because it snakes around the front engine mount, which looks very difficult to remove.  It looks like it would remove straight down if the mount wasn't in the way, and maybe it could be removed and replaced from the top side, but that's very tight with pulleys.  There must be a way to get this part out without removing the engine? This is not a commonly replaced part- the parts guy at the dealer said he has only sold one of these in several years, and I see no mention of replacing it in the 5000 page factory workshop manual or anywhere on the internet.  Does anyone have experience with replacing this part with the engine in the car?  I would appreciate any insight, and would even pay for a solution.  I would like to get the car back on the road.  Summer is very short here in Minnesota.    


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I've also never had to replace that part, but the central front engine mount is in contrast to what you think, easy to remove with the engine in the car. The engine has to support near the front with a jack (work carried out on the floor with jack stands)or with a hydraulic jacking (work carried out on a lift).

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Flanders- Thanks very much for your reply regarding supporting the engine, and removing the front central engine mount. That's encouraging.  I'll try it as soon as I have a few hours, and report back.



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Progress!  I removed the front engine mount to be able to remove the Water Guide Housing.  Access to the top engine mount bolts is very tight, so I used a 15mm crow's foot on a 3/8" breaker bar to break them loose from above.  The mount is slotted for those top bolts, and the mount slips down with the top bolts in place, but you have to remove the studs for the lower mount to do so. Also had to remove the oil pressure relief valve to provide clearance to remove the Water Guide Housing. The seam is broken on the plastic housing about 3 inches long.  I filled it with water, and it drips out. This part is made in France like the water pump that fails often.     


Finally, I can start assembling. Probably need a o-ring for the Henn coupling I opened.  


Anyone have a recommendation for an affordable cooling system coolant pressure tester available in the U.S.?  I was thinking about modifying a spare Boxster coolant cap to adapt to a tester.  

Also, once the coolant is in, is opening the bleeder valve and running the engine enough to bleed the system? I know there are systems to do bleeding, but I'm doing this on a budget.      


Thanks again for your advice on the mount, RFM Flanders!   

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If you have no vacuum filing system it becomes more difficult, what you can do is jacking the rear of the car up as high as possible, open the bleeder valve and slowly fill the system with coolant, let the engine run and top up, let the engine cool down and top up again. This process will be repeated a few times, then go drive around the block, let the engine cool down again and top up, you must keep a very close eye on the engine temp. during the entire time of the bleeding procedure. After a few rides (days?) you can close the bleeder valve. As you can see it is a time-consuming and not always trouble free operation, therefore is a vacuum fill system a must have, the device is not too expensive and you will use it undoubtedly.

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  • 3 weeks later...

Sorry for not posting for a while.  Anyway, the coolant guide housing was replaced, and there is no coolant loss now, opening the bleed valve seems to have removed any air bubbles, and the car runs great. On a somewhat related topic, I just discovered that both of the radiator fans had stopped working.  The passenger right side was a quick fix- there was a small piece of gravel between the fan blades and the housing.  Spinning the fan got it going again, and it goes on full speed with the AC.  I understand that the 987/997 models have a fan control unit which varies the fan speed instead of the two speed feature using a resistor in the earlier 986/996 models. The driver's side, however, probably has been inoperative for some time.  I tried applying 12 volts to the fan connection, and nothing.  I want to remove it, and replace it or fix the motor, but I'm trying to figure out if it can be removed without the radiator.  It looks like it should come out with just the liner removed.  Any suggestions, or a procedure anywhere for removing just the fan with motor? the 5000 page factory workshop manual doesn't cover it, I've seen Wayne Dempsey's procedure for the 986/996 fan, and Pedro's 986 procedure, but the 986/996 fans are significantly different, so I'm looking for a procedure for removing and replacing the 987/997 fan. There are plenty of fans for sale, but can't find a procedure.       

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  • 2 years later...

I wanted to reply to this thread since I also had to replace my coolant pipe assembly (or "water guide housing"), and there doesn't seem to be any mention of this repair anywhere else online.  I'm guessing not many people have issues with this part, so we're in the unlucky few.


My '05 Boxster 2.7 developed a coolant leak roughly a week after I completed a preventative water pump replacement.  I noticed the leak under the front of the engine and assumed that the new pump was the culprit.  Turns out the coolant pipe assembly was seeping from the top, due to a bad seal.  I tried draining the cooling system and using JB Weld at the source of the leak (which was hard to pinpoint, since it was hidden directly underneath a pulley).  This didn't hold, so I also took upon the task of removing this part.


Here are a couple of things I learned:

  • The 4 bolts holding the motor mount are really tough to remove.  The top two bolts are close to the firewall and only need to be loosened, since the mount is slotted around these and can slide out once they're loose.
  • The bottom two have to be completely removed, but they're really long and there is not enough clearance to do this since they hit against the chassis.  I had to drop the motor a few inches to get them at an angle where I could pull them out.
  • There's a hidden torx bolt in the center of the mount that you'll never find unless you know it's there.  The head faces towards the front of the car, and I used a long extension on my ratchet to approach it.  Apparently, only newer cars have this bolt, but my engine was replaced in '11 so mine had it.
  • The engine carrier is attached to the mount and they come out in an assembly, so this has to be removed as well.  There's only 4 nuts holding this up, which are easily identifiable under the car.  Sometimes the studs these nuts are attached to come out as well, which is expected.  It's actually easier if they do, since the mount tends to get hung up on these threads as you try to wiggle and drop it from the car.  Pelican Parts has a good article on "Porsche Boxster Motor Mount Replacement" that I used as reference.
  • There are nine T30 torx bolts holding the coolant pipe assembly to the engine.  They're hard to get to and require a lot of patience.  I believe 3 of them were longer than the rest, so pay attention to where they go.
  • I also had to remove the oil pressure relief valve to get out the coolant pipe.  I'd say roughly 1/3 my oil drained during this process, so be prepared to catch this.
  • The plastic coolant pipe assembly was really hard to get out.  Even with everything removed (timing belt, motor mount, temp sensor, hoses, and oil pressure relief valve) you really have to work it down and out of the car.  I had to put a lot of stress on the lower portion to get it around the spot where the oil pressure relief valve mounts, but this seemed to be the only way to get it clear.

Originally, I was only going to replace the top and bottom seals on this piece, but after going through the work of removing it, I'm going to replace the entire part ( #987-106-508-04).  This is not a job I ever want to revisit in the future.

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  • 6 months later...

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