Hello members, I have an 04 TL original owner and I noticed the engine started developing knocking noise when the engine is warm. At start up the noise is not there but as the engine warms up the noise slowly becoming loud. Here’s the portion of the video. My guess the knocking is coming from the front and back of the cylinder head. could be a candidate for a valve adjustment but wanting to know your experience in this and the fix.

https://youtu.be/KwCt6Nc1GKk

 

It sounds like noise from your lifters. I feel like its pretty common to have valve noise and/or lifter noise on these cars, albeit yours is slightly more pronounced. Doubtful its anything like rod knock, but hearing the engine at different rpms would be helpful.

 

the noise goes away once the RPM goes up to 2k and above. Only noticeable on idle and nothing while driving.

do you think valve service adjustment will quiet this down?

 

you can try, but dont expect it to magically get quieter

 

Valve and lifter noise can be a result of wear and tear, I'm not sure how many miles are on your engine - let alone how well it's been taken care of. But honestly, if you aren't seeing performance issues, I wouldn't worry about it too much. Like I said, valve/lifter tick seems to be more common than not on this car. You can go for a valve adjustment, but there's no guarantee that will do anything.

 

Thanks! I’m currently making a valve adjustment and will report back if this makes any difference.

 

If you're pulling the valve covers, you might as well do the gaskets while you're there, just my two cents.

 

Ok so I completed the valve adjustment and mostly the exhaust side were tight. Intake side on the loose side but not so much. After putting it back together the knocking noise did not disappear. It stays the same in my opinion.

I also decided to add a liqui molly hydraulic lifter additive to see if there will be any help at this point but unfortunately no difference.

also I did a process of elimination by removing the accessory belt to ensure it’s not the power pump pulley or the belt tensioner. Nothing change…

What I’ll do next is to lift the car up and listen more to the underneath of the car. People are saying it could be the timing belt tensioner. YouTube video suggests the knocking noise of the timing belt tensioner is way different from the knocking noise I’m hearing. So I will find out soon when the car is lifted in the air.

 

Hey, this is very similar to my 2005 TL. 170,000 miles. I also did the valve adjustment myself, twice , actually, to try to get rid of the slight knock. of course the noise on mine was in the rear cylinder bank which makes things extra fun. The timing tensioner did go on mine(develops a slight leek and then fails to maintain pressure on the tensioner pulley) and yes that is a totally different noise. the tensioner failure sounds like a loud regular chatter. I even re-did this tensioner again thinking it may have failed again, but it did not help.
After all was said and done the noise never really went away, the performance is no different, and I have learned to live with the noise - same as yours - after 2000 rpm the noise is not audible. good luck!