I have a 2010 RL which I love. Now that it is getting cold again when I start it up I get a somewhat loud tapping/knocking noise from I am assuming the valves. It never happens in warm weather and goes away in a couple of minutes when cold. The car is always garaged. Does anyone have any ideas what this could be and is it something to worry about. I have 74,000 miles and an extended warranty until 105,000. Thanks

 

Are you using the proper weight oil?
Could be the injectors or valves that need adjusting.

 

I'm no mechanic, but I was once told by a Honda mechanic that most engines are like this on startup but because of the J-series design the heads sit in a position that projects the sound of the cold engine heating up. I've had a J32 and now a J35 and they both made that noise and run/ran fine (RL is at 62k miles, CL was at 150k-ish).

If you want the noise to go away try a block heater.

 

I run Mobil 1 synthetic 15W-50 during the summer and it silenced my valve-train by almost 90 percent. I show 157,000 kilometers and the J35 runs like a Raped-Ape in VTEC.
Try the Mobil 1 in this weight...The risk is zero.

 

^lol okay

OP

it is normal for valves to be noisy when the engine is first started on very cold days. oil is thicker, metal is not warm, etc. If you are concerned about it. check clearances when you car is cold and adjust if needed.

 

"raped ape" hahaha... WTF man you got some bad ass Vtakkkk

High weight oils or an additive will help, but it may also mask an adjustment issue.

 

Usually when engine is noisy at cold weather the oil is too thick and engine doesnt get instant lubrication. Usually cylinder head (and lifters) are the first place what suffers starvation.
To my mind it is better use 0W or 5W (that first part of the oil grade) on cold weather.
That last part is the viscosity at higher temps, it doesnt matter if it is 40 or 50 or even 30, our engines wont get so hot (thermostat and cooling system takes care of that)
This explains something
Motor Oil Viscosity Grades Explained in Layman's Terms

 

^Correct on the weight designators. Hondas are engineered for 5W-20. I think 20 is too light for the heat we get in Texas, so I ran 5W-30 in the RL. If cold is an issue, synthetics can go to 0W, but that is only needed for sub-zero Fahrenheit starts.

45 weights and up are for diesel engines and will only hurt MPGs. Well, it can also be used to reduce valve cover leakage in high mileage engines.