chenxingha

Well, it has been more than 9 months and 550+ miles since last December's repair. All was well until the Check Engine Light came ON about a month ago, with code P0440, less the code P0441 than in last December. This time I had another issue which was the exhaust pipe section that has the O2 sensor fitted on had too many holes and break outs, so I chose to replace that mid section pipe first (refer to my DIY post at https://www.clublexus.com/forums/rx-...ed-advice.html).

Then I cleared the code and now it has been more than 2 weeks and 50+ miles: no CEL and no P0440 code.

I know that experts on this thread explained in detail that code P0440 has nothing to do with exhaust leaks, how ever severe the leaks might be. I am just reporting intermediate results back here and cross my fingers for P0440 not coming back - it was so difficult to diagnose.

maxSteel

Good luck. How is that rust repair holding up?

chenxingha

The car has logged another 200 miles and the repaired middle section is as solid as it was on day-one. I think the trick is to leave the rusted pipe as much as you can and let the new section go over them so to increase the structural strength since no professional welder was involved. If the remaining ends were long enough exhaust pipe clamps would work too.

The JB Weld paste would still release ugly smells when heated after 200 miles. But now the smell appeared all gone - an indication of being fully cured?

maxSteel

That's great news. I hope it lasts. I've never had great success with JB Weld but maybe the jobs I tried it on were not a good fit

chenxingha

maxSteel:

I applied JB Weld paste to seal potential leaks of friend's DIY welding. It is doing better than other paste type high-temp exhaust pipe sealer. High-temp silicon sealers don't hold much long from pressure if there are leaks (my prior experiences) in similar circumstance. I am not sure about relying on JB Weld paste for strength.

I will report back in a year also after more miles with photos of the repaired mid section.

chenxingha

Hi maxSteel: I just updated my last October's repair on the mid section exhaust pipe at
https://www.clublexus.com/forums/rx-...l#post11551310
with photos taken a few days ago. After nearly 1k miles (local paved streets, express ways and some highways) since, the repair is still holding up strong.

I remember you asked so to let you know my update.

Thank you for sharing your expertise.