I had a coolant line blow out late last week - got the replacement part, and finally found some time to work on it. It's the twin hard-pipe that runs left-right behind the engine, under the exhaust header. Part #17127518503; #1 on this diagram:

Has anyone ever replaced this piece, or does anyone know of a how-to? I've looked from above and below and it looks like it should be doable from the top. I 've gotten to the bolts by pulling the heat shield that sits above the exhaust header and moving the shield beneath it, but the clamped ends are proving problematic. On the passenger side I've been able to move the clamps off the hoses, but the clearance is tight enough that I can't apply enough force to get the hoses off the pipe. On the driver's side it's even tighter - I can't quite get to the clamps with any kind of pliers I have. Any tips? I might pull the coolant tank (which is already dry for obvious reasons) and try to move the steering reservoir out of the way, but I don't know how much that'll help. Do I have to drop the damn subframe to get this piece out? I feel like this project is starting to MOCK me...

 

The metal pipe failed?

I just finished replacing my engine because one of the plastic coolant tees (#10 in the diagram) broke completely open while I was driving home one evening.

Before I knew I had warped my cylinder head from that overheat, I replaced all 3 of those plastic tees (10,11 and 15) and most of the hoses. That was extraordinarily frustrating - and I'm a dealer technician with tools galore. I replaced the remaining hoses in the cooling system - which included 3 of the 4 hoses that attach to those pipes - when I had the engine and transmission out of the car which made replacing all those hoses an absolute breeze. On my 2003 R53 with 165k miles, the rubber had vulcanized(?) itself to the pipe and since the powertrain was not impeding my access, I was able to use a wire brush on my air grinder to thoroughly clean the pipe for the new hose. I think it would have been miserable to do this with the engine in the car. I do not envy the work you must do now.

The way I see it, you can either remove the exhaust manifold for access from the top or you can remove the right side axle and maybe the starter to get at it from below. That bracket (#23 in the diagram) is bolted onto the lower starter bolt. My car was on a lift and I had not yet bolted the exhaust manifold to the head so worked from above and below (right axle not installed yet) to secure that pipe. Even with all that access I had, it was still something of a hassle to properly secure it.

 

Yep, the metal pipe failed. Went to pick up a pizza....as I got out of the car white smoke started coming out from under the hood. At first it looked like a steady leak from under the heat shield next to the coolant tank, which was hard to process, but as the pressure dropped it was clearly shooting up and hitting the shield from below. Made it the three miles back home without the temp gauge climbing, and then had another bout of white smoke and pissing coolant..

At this point I've got all four hoses detached, and will tackle the bolt to the "holder" this afternoon (gods help me if i break it). Removed the heat shield from over the header, and detached the lower head shield but didn't remove it, just slid it around to allow better access wherever I needed it. Bought one of these for the occasion: OEMTOOLS Hose Clamp Pliers (autozone.com) and it was a big help on two of the clamps, but couldn't budge the other two (driver's side), so I had to carefully cut those with a dremel. Did all of this from above, but had to get underneath a few times to get a better look at things. Got the hoses off the pipe by inserting various small objects, applying WD40, and using a spreader tool I inherited from my grandfather.

Based on your story I should probably take a real close look at the plastic tees and assorted hoses. If I were starting from scratch I would seriously consider pulling the header out and replacing every hose and fitting I could reach. Might make that a near-future project regardless.

 

Finally wrapped this project up a week or so back...I figured as long as I was in there and had the coolant drained I'd change the supercharger oil, and then I didn't want to declare victory until I had the ride back on the road for a few days. But the verdict is, yes, replacing the hard pipe isn't too difficult or complicated as long as you have a few key tools. Specifically, a decent hose-clamp plier to get to the hard-to-reach hose clamps (and to put them back in place), some kind of spreader tool to get the hoses off the pipe (clamping a vise-grip on the pipe to provide something for the spreader to push against) and a wobble socket on a long extension for your socket wrench or breaker bar.



Removing the upper heat shield above the header (two easy-to-access bolts) and detaching the lower heat shield so you can move it around a little (but leaving it more-or-less in place so it protects your steering lines on top of the rack) opens up enough room to get the hoses off the pipe. Used a collection of picks and whatnot to open the hoses enough to get some WD in there, after which the spreader tool & vise-grip combo popped the hoses off pretty easily. Then the only problem is the bolt holding the pipe to the "holder" (#23 in the diagram above) - the holder has enough flex that it twists and lets the bolt pop out of your socket when you apply torque, so the holder has to come out with the pipe, which as ghostwrench noted above means that the lower bolt on the starter has to come out. I finally figured out that if you pull the cooling fan for the steering motor/pump (which is really easy to do), you can run a long socket extension (actually a few in my case) over the rear engine mount and past the support bearing for the right-side axle...a decent wobble socket on the end lets you get a good grip on the bolt, and then everything is easy-peasy (assuming you can separate the pipe from the holder, which you certainly should be able to do since they come out together and you can take them to the bench).



So in a nutshell, this isn't a particularly difficult job, as long as you have a few key tools. Pull one heat shield, detach another, pull the steering cooling fan, and it's pretty straightforward after that.


The essential tools: breaker bar w/extensions and wobble socket. hose clamp pliers, spreader thingy.




Socket and extension in place on the lower starter bolt.

 

Just curious what part of the water pipe sprung the leak? Any comment on the failure cause(s)? Was it rubbing against something, have a bad weld, stress fracture or corrosion, maybe some combo or something else?

Like you, I'm contemplating preemptively replacing all 976 coolant hoses and pipes on this car and maybe the heater core will I'm at it, just so this never happens.

 

It looked like corrosion from the outside, right next to the passenger side bracket that connects the two sections of pipe (the bracket that doesn't get bolted to anything). I figure seventeen years of midwestern-winter road salt was the main cause. The leak was a pinhole but it was in the middle of a corroded patch.