Hi: New guy here on my first post. My 2008 Prius has a strong exhaust odor inside the cabin when the ventilation setting is on exterior air. When I change to interior air circulation, the problem goes away. However the default start up setting is exterior air, and it always seems to change back to exterior air after a few minutes. I know the exhaust is coming from my car because the symptom occurs when I am the only car around. This problem began when the weather got cold, but I don't know if it is really related. Starting to get concerned here. Any advice would be appreciated. Thanks!
Yes, you should be concerned. Check your engine oil filler cap to make sure that it is on, and tight. Do you hear unusual engine exhaust noise? If you can't figure out the problem, I strongly recommend that you immediately take the car to your local Toyota dealer for help. Good luck.
Hi Patrick: As soon as I read your post I went out to check under the hood. Sure enough, my engine oil cap was not on properly. I must have been driving around for a few weeks like that. Oil level looks OK and not much splatter, but I added a little to bring it back up to full. I'll drive it in the morning and see if the fumes go away. Are there any other concerns because of driving without the filler cap? Many, many thanks!
If the oil level did not drop below the lower dimple on the dipstick, then the engine should be OK. The only other issue is that your engine may have been running a bit lean (regarding the air/fuel mixture), as unmetered air entered the crankcase and ultimately into the intake manifold via the PCV valve. However that should not have caused permanent damage.
We drove about 50 miles today, no exhaust fumes in the cabin. Thanks Patrick. Valuable lesson learned. As my wife said "That's a pretty cool website" (Priuschat).
Wow patrick, that was an awesome guess. I only hope you're still around here in 10 years when my prius shows signs of old age.
Hi All, I'm a newbie and have to commend Patrick for his excellent advice. My wife just purchased a used 2010 Gen III from a dealer and we started to smell exhaust fumes in the cabin. So back to the dealer we went this past Friday afternoon. They couldn't find anything wrong but one of the service guys took a small ride with us and did notice the smell. So they at least "documented" the complaint. After coming home that night and doing some research, found this thread. At first I thought it sounded like a very logical explanation and didn't think the service dept. would miss that. But went out and opened the hood - voila! Don't know how the oil cap loosens but you guys saved the day. And now I'm temporarily placed on a "pedestal" with my wife for solving this problem. Can't wait to tell the service manager. Thanks to Patrick and all...... :cheer2:
Glad to hear that this string helped you. Typically, the oil cap will be laying there because whoever last changed the engine oil failed to replace the engine oil cap, before returning the car to the customer. This might reasonably make you wonder how much diligence was employed in correctly installing the engine oil filter and tightening the oil drain plug, or for that matter adding the correct viscosity and quantity of engine oil.
Add to that the institutional price gouging which most dealers seem to indulge in. My passenger low beam bulb went out recently, the dealer wanted $130 to change it. Did a search on Prius Chat and found step by step tutorial help, did it myself with a $10 replacement bulb.
Thank you so much Patrick! My partner either didn't tighten it or forgot to put it back on because it was missing! You helped another... 15 years later!
