Hi
2005 TL 5AT. 160000 miles.
for the last 10,000 miles, a noticeable tick has developed on the rear of the engine. sounds like coming from intake side, passenger side rear cylinder.
Car runs PERECT, no loss of power or change in mileage. just annoying and alarming to hear. Not noticeable upon cold start, because a loud engine drowns out the noise. As engine idles down, noise is there. Ticking noise gets worse with higher engine speed, cold or hot. I was able to get rid of the noise one time, by driving it really hard for a couple miles, but the sound came back, of course.
- recent oil change(5-20 synthetic)
-Timing belt done 30,000 miles ago
- timing belt tensioner changed (twice - because I thought this tick was another tensioner failure)
-new plugs (not loose)
-valve adjustment (I did myself, nothing was really out of spec, even went through this twice to double check everything))
- now the car has a slight smell of burning plastic/electrical burn after starting and idling for a minute. I kept climate control off, and smell still exists.

- In winter, in park, car also has an issue of climate control blowing cold air literally until the second I put it in drive and move. Auto blend-Door seems to open up on its own.
maybe these issues are separate, but I thought I would list everything.

Had battery drain issue until I unplugged HFL(thanks to this site for that info), new battery works great.

Any help is appreciated. This car sits in a garage until winter, and GF drives it, mostly around town.

 

So I found the burnt plastic smell. As others have suggested, I looked for a plastic bag that may have gotten stuck underneath, and bingo, there is the remains of a grocery bag stuck to the bottom of the exhaust. This car barely gets driven, so it was just lingering for months!