Exhaust leaks
The engine on mine has always sounded like it was blowing from the front exhaust somewhere. I found the reason for this was... It WAS blowing! Now this had passed a previous MOT but I suspect it should not have done strictly speaking, anyway I wanted it stopped. The Aixam has a flexible section in the pipe at the back of the engine bay, and this is known to break sometimes, more on earlier examples where the flexi pipe was actually on a bend. I pulled the front section to have a look, as one of the clamps looked hard to get at.
There are 4 nuts on the engine, one bolt on the gearbox, and two clamps on the flexi pipe, of which I left the front in place. I had replaced the back clamp some weeks ago with a Jubilee type worm clip, as the original fell to bits, but the Jubilee I suspect couldn't really grip as hard as needed in this application. The gearbox bolt is hard to reach, you can JUST get a 13mm spanner on the belt end, and a socket across the gearbox from underneath the car:
Note the above was actually on replacing the pipe. The whole section looks like this (new clamp fitted):
Why was it leaking? Two reasons. First the design of the joint. It has slots in the pipe end which can not seal without a sealant compound:
Also the clamp design humps up where the screw compresses it. Now on a thin pipe like the flexi section, which appears to be double skinned, the pipe itself rucks up in the same place, making a nice tunnel for the exhaust to escape! :
I got some ordinary U-bolt clamps, the 29mm size fitted properly. There isn't a lot of spare pipe where the slots are, so the clamp needs to be positioned very carefully near the end. I also squashed them slightly narrower. Also to watch out for? Not much room down there, I shortened the ends of the bolts on the clamps and trial fitted it to see where the nuts could be accessed before applying my chosen sealant.
Slot it all together with sealant and fit nuts and bolts not-quite-tight, then tighten the 4 engine nuts, then the gearbox bolt, then the flexi pipe clamp. All this is to make sure the exhaust doesn't stress when you tighten it up. As you can see, not a lot of room past the anti-roll bar, so having the clamp facing the right way will save lots of trouble.
Well that sorted the front end, the difference in noise was very noticeable :o)
I gave the rest of the system and mountings a good looking at as well, and spotted a tiny soot mark at the mounting bracket in front of the spare wheel - Uh-oh..... Well if I could see it, an alert MOT tester would as well. I wire brushed it :
AAARGH!
Out with the welder. Oh, and the mount refused to unscrew, it sheared instead :o(
The mid exhaust joint near the handbrake lever needed to come off, it was very tight (but had a u-bolt). I gave it a mild crushing with a mole-type grip, and also heated it with a gas torch. It let go.
I needed a mount in a hurry, and toured the accessory and spares shops. The nearest I could find was a slightly larger one, with M8 instead of M6 studs. I decided to change the thread in the alloy rivnut in the chassis and fit the larger one.
Since the exhaust at this point tended to graze the chassis hole it passes through at this point, I also cut off the original mounting tab and made a new one slightly to the side. I need more welding practice..
Here ends the exhaust saga - for now! I can now hear all the other noises I never worried about before ;o)
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