A little over a month ago I purchased a 2006 TL 5AT. Within the last week I've noticed that upon a cold start up (further more so when it's a little chilly in the morning as well) that there will be a slight knocking sound coming from the passenger side of the engine bay. My first thought is possibly the timing belt tensioner or the serpentine belt tensioner. I dont see the serpentine belt flapping around or causing a knocking sound though. The knocking sound does goes almost completely away once the car is up to operating temperature so that kind of confuses me a tad. Any suggestions as the what the noise could be?

 

Timing belt tensioner is a common issue with the TL.

This is the issue, this little thingy.

Check this video

 

Yeah I've seen that video Haha I was just thrown off cause the noise goes almost completely away once the engine is warm. I'll definitely look into it though. If only it was a 5 minute job to take the timing belt covers off...

 

I just had this EXACT problem, cold engine - loud tapping sound from timing cover area, gone once engine warms up. For me it ended up being the timing belt tensioner, it was leaky as hell. I took the timing covers off, the belt wasn't exactly tight but didn't have major slack either.






I replaced the tensioner without taking off the timing belt or crank pulley. I took off the power steering pump and the upper covers, then the lower splash shield and used something to wedge the top-left part of the lower cover to get access to the timing belt tensioner. It is possible to replace it but you may need nimble fingers, pulling the grenade pin on the new tensioner was a b!tch.

 

99% your tensioner. I replaced my serp pulleys nope...tappin was still there. It will only get worse and actaully never go away. I orderred a tensioner and will be installing this weekend. keep in mind driving with a bad tensioner is driving on borrowed time you don't want to have to repay if it goes and the belt comes off

dealer wanted $900 lol
tensioner cost $30

if you can diy go for it

 

Thanks for the replies guys! I decided to go ahead and just order the Aisin timing belt and water pump kit for the car. It has 176k miles on it and the belt has been replaced once already but its due for a replacement soon anyways. Hoping that solves all of my issues. If not, well, the timing belt was gonna get replaced within the year or so regardless. Better safe than sorry!!

 

don't forget to reseal the oil pump assembly while you have the TB/WP out.

 

Okay.. I've heard a lot about oil pump seal! Haven't really looked too much into it to see what I need to do though. Thanks for the heads up though!