AC smells like cat urine

[concretejungle]

Not sure what happened, I have not hit any cats that I'm aware of. We do not have any cats at our house or around our house. One afternoon leaving work I turned on the AC it the small of cat pee was blasting out of my vents! I actually popped the hood to make sure there wasn't a cat under the hood!

Any idea what could cause that and what to look for?

 

[2021 LC200]

I have heard a mouse can get into the HVAC inlet via the fender and water drain areas of the cowling, then climb into the HVAC inlet and land on top of the filter (passenger side, make sure to have AC in recirculation mode when removing the filter - i.e. do not force the recirc mechanism/door open by hand to get to the filter as that will brake the door actuator mechanism).

Steps I recommend:
- check what you find by removing and inspecting above the cabin filter
- depending on evidence of mouse deposits or even a dead mouse consider 1) remove the cowl and install a fine mesh on the inlet and 2) get an ozone generator to clean the car of smells (note these ozone generators are deadly for mouse’s and roaches etc so run with the door close and AC on in recirc mode and turn off then open the doors holding your breath and let it vent for hours. Do not do more than 1 hour or the car will smell like ozone for weeks…

Good luck, hope you are not to afraid of a dead or alive mouse… If so time to get over it

 

[2021 LC200]

Please search and look online at videos of how to remove the 200 series cowling as it comes off in a specific way otherwise you may damage clips and create a water leak as a result (seal between cowling and windscreen is key).

 

[Sandroad]

I agree with @2021 LC200 there is almost certainly a mouse nest complete with pee/poop in the area over the cabin filter. Happened to me. A thorough cleaning with a mild vinegar solution solved the smell.

 

[Kinnada]

some think antifreeze smells a bit like cat pee. check for any leaks?

 

[CanadianRockyCruiser]

It's worth inspecting the evaporator core drain (above the transmission). When evaporator cores maintain water for too long, things can get moldy and start to stink. If it's a clogged drain evaporator core drain, try to clear the clog and then consider cleaning the core with A/C system cleaner (some products are called evaporator core cleaner).

Boroscopic inspection may be your first course of action. If it's an evaporator core leak, you can probably find it with a long borescope. If it's a mouse, you might find that too! Same for mold.

 

[gasman4u]

I was going to suggest the prospect of mold too. There’s a way to get rid of it, but it’s a multi step process with a couple cans of stuff iirc.

Not exactly detailed in remedy, but my bet is condensation within your system was left too long too many times and you’re smelling it. I hope to be wrong though. Post what you find.

 

[hoot504]

I live in the urban west (not a particularly mouse heavy area) and also had the mouse issue. Never found the guy but went to replace my cabin air filter one day and found his little house he built.

 

[concretejungle]

I'll check out some of these suggestions. It started after being parked at the airport for 12 days while I was in Tahiti. Came home and just turned on the air last week for the first time. So maybe a mouse while sitting there, or I could see mold. But it certainly has a strong odor of almost like when a cat sprays something to mark it's territory

 

[2021 LC200]

Given symptoms the cabin filter check is quick and can rule out critter issue.

Removing mold or unplugging the AC drain is (a lot) less easy. The evap drain for the front AC exits above the transmission in the middle and is not really accessible from below. I would try these steps in this order, even with a plugged drain, before somehow managing access from below:
1) Get that ozone generator and run it for 1 hour in recirc mode through the evaporator. Brakes down mold. Together with water condensing this may clear the drain with some luck (if that is the problem).
2) Next more involved is dropping the passenger side footwell panel, remove glove box, remove some electric module and get access to the bottom of the fan. Remove the motor/ fan (three bolts, dropping it). As part if this you will have to set aside the passenger footwell airbag unless a 2015 does not have that. So make sure you remove the negative from the car battery such it does not explode in your face! The connector on the airbag can be removed as well. There is a certain way to do that (typically a clip needs to be shifted and then it pulls off). Now you have a view and access to the flow path into the evaporator. Use a AC evap foam cleaner with hose, push the hose in and repeat foam several times. As part of this flushing with some water may help as well although condensed water will do it as well. Once the drain runs foam again and let it sit. Close it all up. Consider repeating step 1) above.

I must say Mr T did an awful job not extending the drain around the transmission as part of the design. Good thing they did a great job on most of the rest of the 200 series.

When you get AC evap foam have a go at the rear AC as well. The drain is accessible from below via the rear driver side bumper panel.

 

[2021 LC200]

Although this is the driver side knee airbag shown, I recall the connector is like that on the passenger side as well. The little "clip" as part of the connector needs to be pulled up (direction of the blue arrow I added) and then it pulls out easy. Install is push in connector and push down the clip.

Again make sure to disconnect the battery or it may blow up on you, not good...