Question Tapping noise when cold

[satx]

2008 Tundra 5.7 Reg Cab with only 3,500 miles. Tapping noise when slowly excelleration from a stop. Noise is most notible the colder the outside temp. Fairly loud tapping below 50 degrees, only slightly noticable below 65 degrees. Tapping goes away after driving for five minutes. Tapping does not occur when first started or revving engine in park. Problem only occurs when truck is in put in gear and gently excellerated under normal load.

[Sean Dempsey]

I experience something similar. I don't have an explanation. 2008 DC 5.7 with around 5500 miles.

[Lukin]

I have the same issue with my truck. I have been told that is the VVT ( Variable Valve Timing). Apparently the valves stay open longer when it's cold and that creates the diesel like tapping sound. I am not much of a motor head so I don't really know what the valves staying open longer accomplishes.

[Amkeer]

Entirely normal. If you are concerned about various noises your engine makes let me make a suggestion, you wait until after 15,000 miles on the odometer, then send in an oil analysis. This oil analysis may be able to indicate whether or not there may be a mechanical issue, which would be highly unlikely.

Enjoy your truck.

[93to98]

same noise here, also goes away after engine is warm, 2008 crewmax 4x4 11500k

[augustus88]

Same here on '09 DC with 2,430 miles.

[DesertSandAZ]

Same here, 07 Double cab 50k miles.

[byofcer95]

yep here too

[wildbill129]

This noise has been talked about on this forum and others many times. It kind of sounds like a diesel, right?? It is a normal function of the truck...here is a HUGE thread on it:

5.7 cold start KNOCK

[Mr. Creosote]

Me too......

[ClevelandTundra]

me too...

[baxter7789]

same here, its always done it on my truck ever since day one

still doing it 2 years later and 47000 miles later

never had a problem tho.

[bnardini]

I have noticed that this is a problem peculiar to overhead cam engines. I have owned a few different OHC engines over the years (since the 50's) and to one degree or another they don't run smooth until the valves are warmed up. My 08 Tundra with the 5.7 is the best engine I have ever had and it does not like full throttle until it is a little warm.

[Gary419]

My 5.7 is also doing it but never goes away when warmed up. Mine starts after warmed. Thinking about having dealer look at it, but it really is only noticeable under accelleration. Dealer service people aren't usually into test drives to hear noises.

[DawgBonez]

Same here... Once it's warmed, it goes away...
I stuck a long screwdrier to my ear and found that it seems to be coming from my injectors... I opened the oil fill cap and quickly realized that it's definetly not valvetrain...