Weird Smell - AC?

So, last weekend I stopped at a store, and left my wife in the truck with it running and the AC on. When I got back to the truck (about 10 minutes or so), I noticed a pretty pungent smell outside walking up, and also heavy inside the truck. My wife, who is hopelessly oblivious to smells, said she didn't really notice , but also said she put the ac on recirculate after we parked (it was on when I got back in). The smell was odd, and I couldn't really put my finger on what it was. I thought the guy I parked next to, who was sitting in the car with the windows down, had started smoking something, because the smell was like a pungent smokey sweet type smell. I know vehicles aren't air tight, but that doesn't really explain why the cab would smell so heavy with the AC on recirculate.

I don't really know what refrigerant smells like, but I've read it has a sweet type smell, so I've been a little concerned it could have been that. The truck only has 700 miles, so it doesn't really make sense that it would be dumping refrigerant so bad that it would smell that prominent. The ac is also still blowing cold, and I haven't really noticed it in the same way since, but there is still a faint presence of the smell when turn the air on (AC or not) at first. I changed the cabin air filter (because it had lingering smell), but that hasn't done away with it. If it really was something from outside, I guess the smell is currently lingering in the evap.

Sorry for the novel. Some other perspective could help. I dont know if i'm ready to take it to Toyota to see if they'll rule out the AC by checking pressures. Just an odd circumstance.

 

Since your 4Runner only has 700 miles on it - the smell is likely normal. New paint on the engine block heating up, protective coatings on metal surfaces that get hot (exhaust manifold), etc... Some type of fluid (power steering, transmission, coolant) could have splashed onto parts of the engine that get extremely hot at the factory. My 2023 4Runner had some unusual smells in the garage after driving it for a while right after we got it. Probably normal - but if it doesn't go away pretty soon get it checked out. Also, check to see if a plastic bag hasn't gotten up under your engine. Like a normal plastic grocery bag. Had this happen once with my Tacoma I had before this 4Runner. Plastic bag blew up under the engine and parts of it melted to the exhaust manifold. Smelled a lot like what you describe.

 

I still catch some occasional new smells, but I know what that smells like, and most of that has well burned off by this point. I was also just under the truck looking at stuff for an unrelated purpose and there's nothing abnormal there. I'm pretty confident those wouldn't be the case here, but i appreciate the feedback.

 

I pulled/inspected/changed cabin air filter. All looked good aside from the filter other than it that had a lingering smell from whatever it was. I'm hoping to not have to resort to cleaning the evap. I'm giving it a while longer to see if the initial turn on smell dissipates as i've only driven it a few times since then.

 

Your SUV might have too much oil in it. The dealership overfilled my oil in the Corolla twice. It comes out the vents.

 

Motor oil? Still on factory fill and it's right on the full line. Thanks.

 

That’s how they overfill I think by going by the line. I don’t use that line at all.

 

@TCW1184: he’s joking. Surplus oil doesn’t come out the vents.

 

lol, yeah, obviously not. Just didn't want to be mean about it if he had some train of thought he was serious about.

 

You are nicer than I am.

 

This might not be your problem but worth a watch: https://www.youtube.com/watch?v=xb0fDfzV41I

In summary:

Keeping the AC on recirculating mode can cause mildew to build up in the system. He recommends you turn off recirc when its not necessary after the car has cooled down and use outside air, as well as turning the AC off five minutes before you get to your destination to air out the system from moisture build up.

The newer 4R should also automatically open the vents to outside air when you shut off the engine, you can customize that setting with Carista ODB.