During the summer I got a ‘96 Renault Laguna for 200e. It had some stuff to fix before I could get it MOT’d. But two busy nights later I got everything sorted out. As a bonus it had an installed driver’s education brake pedal.
Couple of weeks ago I was driving to visit my parents but the poor Laguna broke down on the way. The performance started dropping on highway and I turned back after I noticed that the top speed was ~105 km/h.
Soon I couldn’t even reach 50 km/h. At this point I also noticed that the first parts of the exhaust pipe were red hot. I tried to drive further by having short cool down pauses but eventually the car couldn’t even move on its own power. My friend towed me for the last 10 km.
Yesterday I started to fix it. My guess was that the catalytic converter was blocked as the symptoms hinted that this might be the reason. I started to remove exhaust system parts and soon I was very sure that the catalytic converter was the culprit. I cut it off and opened it.
The converter had two separate cell units inside and the rear one had loosened itself from its place. It had bounced inside the casing until it had managed to find a new form that was able block the flow. It could move freely inside and in the worst position the cells were in 30 degrees angle against the flow. The heat insulation had also disintegrated between the cell units and causing even more blockage.
I fixed it by removing the disintegrated cell unit and heat insulation. I wrapped the intact one tightly in new heat insulation and welded the casing back together. Sadly I forget to take picture of the surviving internals. Now it has only half of the converter material left but I’m pretty sure that it will still pass the emission test.
I could get a new converter quite cheaply but removing the exhaust pipe from the exhaust manifold seemed to be nearly impossible without braking the badly rusted studs. The studs are removable but it’s highly unlikely that I could do this without removing the whole exhaust manifold. The converter wasn’t the car’s original unit as the exhaust pipe had already been welded from weird places.