I'm looking at buying an '06 LX470 with under 100k mi. After a 20 min test drive, where it felt perfect, there was a clicking/ticking sound when I turned the car off. It gradually subsided, but only after about 2 minutes. Most of what I've heard and read is that this is the exhaust system cooling down, and nothing to worry about. What I don't get is why does this one do it? I've driven several other LXs nearly identical to this one, and they didn't do it. Why this one? And is it something that doesn't indicate a larger problem, and I would just have to live with?

Thanks.

 

Looks like time to get underneath it, remove the bottom metal, and check exhaust pipe mounts and heat shield mounts and clearance from front to back. The noise(s) are random. "Larger problems" are fixed by seeing what's under the body. I doubt you'll have to live with it.

 

I have this on my LX, my wife's Forester, and I've had it on other cars as well.
Most commonly its the cats burning off any left over fuel once you turn the car off.
Without hearing it in person I can't say for sure but how you are describing it makes me lean toward that.
If it sounds like dropping ball bearings in a can (sorry, best analogy I can think of), it's probably the exhaust.

If you use a long screw diver you can touch the metal tip to the exhaust (preferably the mid pipes with the cats) and put your ear to the handle end.
The sound will amplify through the screw driver and be very loud if you are in the correct place.
I do that for rattles, squeaks, bearings, etc.

 

Thanks for the replies. KiPod - that ballbearings in a can is a really close comparison. That being the case, if it is the exhaust, any thoughts on what the fix would be? Simply a matter of tightening connections?

 

I personally feel there is nothing to fix.
Try going on a longer test drive but maybe it's just the age of the cat that can vary the sounds you hear.
My LX has 174k and my wife's Forester just over 40k.
The cat is just doing it's normal job and you are hearing it..
Once the cat heats up it reignites and burns off any extra fuel that doesn't burn in the engine.
The "mini explosions" happen in the cat all the time but with the engine running you probably wouldn't notice it because of extra noise and flow pushing the exhaust through faster.
When stopped the exhaust just sits there.
This is why any car without cats smells like a gas station.
Think old muscle cars, etc.

 

Thanks, I get the concept of why it's happening. Just more a question of why you hear it in this car (and yours and your wife's), but not others. Why in this one with 95k miles and not in two others, just like it, that I've driven with 135k+. I'm sure this wasn't happening when they came off the lot. Probably more a curiosity than a concern at this point.

Thanks a lot for your feedback. Really helpful.

 

I remember the Forester doing this from the moment we purchased the car new.
It was a little louder than most cars in my opinion.

Could be age of cat, amount of fuel being sent to engine, length of drive, or any number and/or combination of things.
Air/fuel ratio sensors, mass air flow meter, coolant temp sensor, etc. would affect how much fuel the engine receives and that could be the cause as well.
More fuel sent could lead to more fuel un-burnt in the combustion chamber which would lead to more fuel being burnt by the cat.
I've driven TONS of vehicles and heard enough of it that I don't even pay attention to it anymore.