Exhaust inside car.

Besides the openings in the firewall, of course, I can think of at least two: the rear floor service hole cover, for access to the fuel tank and pump, and the opening for the frame wire, the high-voltage cable for the hybrid battery. There are also many PriusChat threads about water accumulation in the area of the auxiliary (12-volt) battery; sometimes the body rusts through.

 

Back story: year of car ? Has it ever been in an accident? Do you smell exhaust when the windows are down or up? Do you have a rusty car.ie you live in the rust belt. You could have rust holes in the car and exhaust is leaking in. Etc.

SM-J737T1 ?

 

What about the battery cooling fan.......which draws air from the cabin IN through a grill at the lower front of the back seat .....and expels it somewhere ?
What if that fan is not working ?
Could exhaust come IN through what normally is the exit portal ??

Until you get this solved, I strongly suggest that you NOT use the re-circulate feature and keep the fan running at least a little bit above minimum.

 

Check if the oil fill cap is on.

 

Excellent idea.
But one would think that would be present in the front seat too.

 

Go on you tube and look up PRIUS INSPECTION it will show you how to put the engine in inspection mode where the engine will run
continuously for inspection.
With the engine running endlessly idling I would get under the car and check from the muffler all the way to the cat. Listen for an exhaust leak.
Or take it to a muffler shop as some offer a free exhaust inspection. Inspection mode is handy if the muffler tech wants the engine to stay running for a test. He may have a carbon monoxide sniffer.

Your muffler is probably rusted out..

 

Better yet...go to a reputable exhaust shop. They have the tools and experience to tell you why, where and how to fix..

 

If only someone had mentioned that.....

 

I would think that the fan would run all the time.....but at a VERY low speed when not really needed.

 

What about the rubber plugs that were supposed to be installed underneath the car by the dealer as part of the Pre-Delivery Inspection? Check if they were installed...

 

We were missing one of those, go figure. Still, they're not exhaust related; think they're for stabilizing pins of some sort?

 

I think the point was that the hole might open a path into the cabin.

 

Exactly, especially if there is an exhaust leak in the general vicinity of the hole(s)...

 

Those holes are for locator pins, fairly certain they're not mouse access tunnels to the cabin interior. And as quoted, one of our gaskets was missing for a few years; no exhaust smell noticed.

 

There are rubber drain plugs in the hatch floor. One under the spare tire one in the bottom of the 12 volt battery well.
My car leaks water cracked hatch valley but its garaged so not a big deal but I did drill a hole in the center of the battery well plug to keep the battery well dry if caught in the rain. Did not remove the plug as sometimes need to park it outside and there’s rats in Florida. Big fruit rats.

Never have smelled exhaust. You will only smell exhaust if you have a leak.

Side note once when I was lubing the chassis I was under the rear and had some high temp spray header paint And painted the muffler just to see how well the paint lasted. It’s been about 10 years and paint still on and muffler looks new.
If I lived in the rust belt and had a new car I would paint the entire exhaust system especially at the hangers and connections. It works.

 

That could mean that you had no leaks in your exhaust system too.