This may be a normal part of my engine's functionality, but I was curious about your opinions on this. I have a 2008 TL and when I start it in the morning, I get this loud click sound in the engine compartment just after I turn the key. A relay perhaps? Not too sure...It only happens when the engine is cold.

 

its the relays probably turning on the fuel pump. Turn the car into mode 2 (1 before start where all the lights are on but the car isn't on) and see if you hear that same click

 

I don't hear a loud click when I turn it to position 2 without starting the engine. I only hear it when the engine starts. I to hear it first thing in the morning after I leave it overnight.

 

from what i can understand - that "clicking" noise is normal. it's a common concern though - I worked for acura of bellevue over the summer, for parts that is , and that clicking noise was commonly heard on all the serviced TL's: 04-08.

 

The first time my AC compressor engages in the morning it's very loud. After that it's not bad. Easy enough to try, start the car without the AC or defrost on.