I'm pretty sure I already know what's going on but I wanted to tap the collective knowledge here to make sure...

Since the engine is already out of the car and at the rebuilder, I decided to finally getting around to replacing my exhaust from the header back. When I got to the axle back section, I noticed a green residue at the exhaust joint near the diff. I haven't gotten the exhaust off yet because dealing with those farking hangars with a sprained wrist is annoying.

I never had significant amount of white "smoke" out of the tail pipes (beyond what you usually get during Chicago winters). I did have an issue with coolant coming out of the overflow tube during hard romps but just figured it was from overfilling.

So, coolant seal failure?

 

i dont think that has anything to do with coolant but i will buy you a beer if you can actually seperate that pipe from the muffler. its damn near impossible

 

Steel rusts black or red/brown and I'm not sure what else in the exhaust stream is green.

Can I use a plasma cutter?

I have a cat'd midpipe and Tanabe catback going in so I don't really need the pipe.

 

I don't think it's coolant either, it would take a noticeable exhaust leak for it to get out of the pipe, and it wouldn't be a nice uniform coating. Perhaps road salt reacting with some kind copper or zinc based anti-seize Mazda put on that joint?

 

nap, i mean taking it apart in tact, as in two useable pieces. i think its impossible. i really doubt that **** on the pipe has anything to do with coolant

 

That's a good point I hadn't thought of...

Okay, I'll stop worrying unless I find cooling actually pooled in the exhaust system.

 

Because of that damn joint, I had to transport my catback, with the pipe attached, inside the car once. Muffler in the trunk, pipe running into the cabin through the truck pass-through. It fits!