The '04 Camry 4-cyl has about 175K miles. Driving today (many legs, ranging from 5 blocks to 10 miles on the interstate), I began to notice exhaust smell. As I continued, I thought it was maybe from the traffic (including a diesel bus). But then the smell did not dissipate when the traffic thinned. Late afternoon, I called my Trusted Independent Mechanic, who can take it day after tomorrow.
A quick Google search indicates that a likely cause is an exhaust leak. Question 1: Shouldn’t I hear some sound if there is an exhaust leak bad enough to put fumes into the cabin?
One additional weirdness: Last night I had popped loose the heat/AC control panel (shown in pic below) to change a light bulb. I was driving with the panel ajar, hoping to install a replacement bulb before popping the panel back in. After a while I popped the panel back in, and the smell maybe decreased. Question 2: Do any of you experts have an explanation as to why exhaust smell might be coming out of that panel opening?
Question 1: No. A leak will not always result in noises you can hear
Question 2: Refer to @Tester’s answer… That seal is 20 years old if it is even still there
Exhaust leaks can kill. They need to be repaired right away.
Thanks for the advice. I’ll look at the seal today. (Everything on this car is 20 years old. That’s my main concern about it. “Outstanding condition! Runs great!” Really. I just need to swap out all the elastomer parts.)
Car will be used but little until it goes to the mechanic.
At that age, I would consider the flex pipe in the exhaust as a primary culprit. Do you live in a cold climate? Around this time here, I can easily spot most exhaust leaks just looking for the thick vapor being produced right when the engine is started stone cold.
old_mopar-guy – . But the jack to hold up the radiator cap probably costs more than the car is worth.
TwinTurbo – That sounded good. Current temperature here in the DC area just above freezing. I ran out to the carport and peeked under the car. It looked kinda rusty, but I could not see well enough (and I’m to old and wimpy to crawl under the car in this weather). I opened the hood and started the car. I saw no obvious vapor, nor any obvious smells in the engine compartment. (The hood seals looked and felt fine. Exhaust smell was obvious at the tail pipe, where it is supposed to be, but no vapor.)
I’ll run this test again tomorrow morning when I first start the car. Than the car goes to the mechanic after my morning errand.
Do some exhaust leaks occur only when the system has warmed up?
Hard to say what’s causing the exhaust odor. With leaks of any kind, exhaust, coolant, oil, etc, you or your shop must test or inspect to eliminate each possibility, one by one. Good ideas where to start looking above. Since you noticed this immediately after fiddling w/the heater vents, that seems like the mostly likely place to start looking .
Mechanic reports crack in flex pipe and another crack in a connector pipe (I forget which one). Fixing those should take care of the exhaust smell. I suspect that the problem has been there for a long time, but most of our rides are five to 30 minutes so we don’t notice the smell and the effects.
That’s the good news. The bad news is that, looking at other things I had asked about, the mechanic found oil leaks in the valve cover and elsewhere.
And a leaking rack & pinion, to the point where one boot is saturated and torn. Art gets a new rack and pinion.
I mentioned the total cost to my daughter. She asked, “Is the car worth that much?” I said, “To me it is.” It’ll be good for another 80K miles, which is ten years at my usage rate, and I expect/hope that my kids will have taken the keys away by then. And to get a replacement would cost, like, $30K for a car I would not like as much.
Thanks, again, for the advice. See you later with the next problem :>)
(George_San_Jose1 – Just FYI, I did not mess with the vents. That control panel is entirely electrical/electronic. It connects to the car via two multi-pin plugs.)
I had an '03 Camry w/4cyl. Had to replace the flex section at a very early age due to bottoming out on a gravel section of road. Normally part of an expensive section of pipe- maybe even the manifold, I found an exhaust shop nearby that made their own repair sections due to the cost of the OEM parts. They charged only a fraction of the price for an OEM part and it lasted the rest of the life of that car- 15 years or so. I recall the guy saying- be glad you don’t have the 6cyl, those are really expensive!
I wonder how the mechanic discovered that? The flex pipe is usually encased in a wire fabric mesh, so the actual exhaust gas-containing tube inside the mesh isn’t visible.
. But the jack to hold up the radiator cap probably costs more than the car is worth.