Last winter I stored my 1988 trans am in a pole-shed and when I picked it up there was a strong odor (mouse dropping) from the air conditioning ducts and rattling from my blower motor. I pulled out the blower and found a large nest made out of the firewall insulation. I vacuumed out what I could reach and drove around without the blower motor in for a few weeks (and windows down) and researched what I should do next.

After letting everything air out, I put the blower motor back in but there was still a faint mouse odor. I ended up pulling the lower passenger dash panels to get at the heater box for cleaning, which ended up being free of mouse droppings, but I discovered my heater core was leaking. I pulled out the heater core and I am about to start the process of putting it all back together but I wanted to know if there was anything else i could do while everything is pulled apart to get rid of the mouse smell. I tried removing the top of the evaporator? coil case that the blower pushes air into but wasn't able to get it off . I believe there is probably mouse residue at the bottom of the evaporator? case that I cant get at from the blower motor hole.

If anyone has any suggestions what my next step should be let me know. I can take some photos or clarify anything if I was unclear. Thanks.

If you want to go all the way it is possible to pull the entire dash and take apart the various air directing tubes, but it's not for the faint of heart. There's always the possibility of pinched wires, etc when reassembling. Since the blower had been running it's always possible that some got pushed into those areas though ¯\_(ツ)_/¯

Thanks for the quick reply.

I don't think anything got pushed through the duct work in the dash, I'm more worried about mouse residue in the ac evaporator box. The side that feeds into the air box and heater core is clean. My ac blows cold air and works well so I don't want to dismantle that system to get at the box for cleaning.

Just spent the last hour and a half trying to line up the new heater core in the air box and through the firewall but it is proving to be as difficult and frustrating as I've read. Seriously considering bypassing the heater system all together to clean up some space under the hood and for piece of mind of not having to worry about leaks inside the car again. I only drive the car from April/May to September/October in Wisconsin and don't plan on selling it. It's a 305 tbi so there is plenty of work I have to do before she's "finished". Having that cleared out would definitely help in the future for any projects I undertake under the hood.

Any comments or recommendations would be greatly appreciated.

It's EXTREEEEEEEMLY EEEEEEEEZY to take THE WHOLE evaporator housing off.

There are about 4 fasteners around the top on the engine side, and about 3 or 4 around the bottom on the interior side. They're larger than the ones that take the top off; maybe some 10 and/or some 13mm heads.

I would NOT recommend "cleaning up the engine bay". That's just hilljack for "hack off things I don't understand and turn my car into another manufactured home lawn ornament".

Evening S.K.D.
So by removing these fasteners you have easy access to clean the evaporator of all the years of gunk that has been sucked in?

Thanks in advance. Knowledge is great!

By removing those fasteners, the ENTIRE evap housing comes off. EVERY piece of it, leaving a smooth firewall with one big round hole in it and nothing else. You can disassemble it, clean it, repair the holes right above the exh manifold where the material has crystallized and turned to dust, replace all the rubber and foam seals, and even, clean it. It's awesome.

Thanks. My next project. Have to wait awhile till it cools down here of convince the wife I need AC in the garage.