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Old 03-31-2006, 08:44 AM   #1
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Coolant expansion tank replacement

My time has now come to replace the coolant expansion tank as it's leaking and I am a little uncertain about the task at hand. I have searched all the forums about the process and other's experience with this and have read mixed things about the difficulty.

It seems that the real pain is getting up underneath the engine side of the firewall to replace the three inner water hoses while the tank itself and the outer three hoses (plus oil filler and dipstick) are readily accessible from the trunk. My question is if I do NOT replace the three inner hoses is it really as easy as it appears.

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Old 03-31-2006, 08:52 AM   #2
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This would be a good time to buy yourself a Bentley Boxster repair manual. I just read up on this and it has pix on removing it and what's involved.

John (from Atlanta) has done this swap and can tell you what he did and why.
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Old 03-31-2006, 11:15 AM   #3
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not nearly as easy as it appears. i did mine from the top; it's doable but it's tight. the real issues are the hose clamps. if the hoses were a LITTLE longer and could be fastened from inside the trunk, it woule be cake. alas, this is not the case.

get yourself a good set of locking hose clamp pliers. i got mine from pep boys; it looks like a brake cable from a bicycle with pliers on the end.

if i had this to do over, i'd replace the hoses with longer ones. i'd tighten the new screw type clamps in the trunk and then push them through the firewall. this isn't a difficult job, but it IS a hard job. it's a real knucklebuster.
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Old 03-31-2006, 02:12 PM   #4
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Tool Pants posted a thread over at www.renntech.org about his experience replacing the coolant tank.


Just as Insite pointed out, I have read elsewhere that the Bentley manual is skimpy on the details on the coolant tank replacement. Tool Pants gets the job done (of course) but I think you will see a whiff of exasperation in getting to the hose clamps.
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Old 03-31-2006, 08:24 PM   #5
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Never met a hose clamp that could beat me.
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Old 04-01-2006, 06:56 AM   #6
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here's the hose clamp tool:
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Old 04-13-2010, 03:23 PM   #7
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Coolant expansion tank replacement

Funny you should post this thread, since I'm holding my new tank in my hand and are thinking exactly the same thing. At first glance my new tank does not have a hole for the dip-stick on it (even though it´s marked), so for me getting that hole done it’s the first step. Then comes the hose clamps on the hoses that attach to the old tank, after releasing them I’m pretty sure they’ll be useless, so I already got myself some metal screw clamps to replace the old ones. Then there is the electrical plug that needs to be reused, once the tank is removed. But I’m even thinking that clamping the hoses before they’re released should be enough, meaning probably we won’t even need to drain the coolant from the car at all. Anyway….. I think more than 1 person out there must have done this already..... can you help us both here?
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Old 04-13-2010, 04:48 PM   #8
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What a nightmare. I couldn't figure out (and still can't) how to get to those hoses. Luckily, I was able to go a different route. Placed some JB Waterweld over the hole and good as new. Finding the hole underneath was a bit of a problem too, since I had to feel for it.
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Old 04-20-2010, 06:48 PM   #9
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It is a real pain, but it was worth it to me in the end. It took me about 5 hours, but I learned a lot about the car while I was in there that gave me the courage to do every repair on her since then. I wish I could remember how I got the three little hoses connected, but it's been awhile. I remember disconnecting the oil filler hose and being able to reach one or more of them.

I replaced the clamps on the small hoses with stainless screw down clamps which made it easier to put the new hoses back on.

Good luck!
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Old 04-20-2010, 09:59 PM   #10
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My experience:
As others have pointed out, this is not a technically challenging or difficult job, just hard because of the limited access to the hose clamps on the engine side of things. I initially tried to seal the tank with JB waterweld but this did not work for me. I finally bit the bullet and bought the tank from local dealer (should've bought it from Sunset).
I used the instructions published here: Link. I think it took me about 4 hours total.

Probably would have been easier with a hose clamp tool. I didn't have this. I used a long curved needle nose plier.

To answer some of the questions:
My new tank also did not have the hole for the oil dipstick so I drilled that out first, very easy.
It is a good idea to just drain the coolant first because it will make refilling easier and particularly purging the system of air at the end.
No matter how hard you try (trust me) you will not be able to get away by doing this all from the trunk side only, you will have to get a hand or tool into the engine side to release the clamps. It's not a matter of replacing the hoses (I did not), but a matter of releasing the clamps and hoses from the coolant tank. I would suggest replacing the clamps with screw type clamps while you are there.
I also did not buy the ridiculously expensive Porsche Coolant. I used Prestone Extended Life.

Good luck!
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Old 04-21-2010, 04:57 PM   #11
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Sign me up. Just picked the car up today. $800 later... new expansion tank.

$400 for the tank and $400 for labour.

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Old 04-28-2010, 04:29 PM   #12
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Expansion Tank

Yeah! The tank and labor $$ does hurt. Make sure though that you get the latest, correct tank cap as you will only excellerate the destruction of your new tank.

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