I got my 2010 Tundra in Jan. of 2017. Did the usual upgrades. K&N, Flowmaster, Spoolin Shift kit, S.A.B.M. At some point I started to hear noise from the left bank valve cover. It was intermittent for a while but slowly became a constant nuisance. It's never good when your wife and daughter say that your truck sounds funny. I wasn't ignoring the problem, I was researching the problem. Several forums, You Tube videos, and websites lead me to believe that the timing chain tensioner was bad. Listening to the noise , my minds eye could see a chain bouncing around a sprocket like a kid about to lose the chain on his BMX. The final straw was on my way home from work. The noise had grown quite loud. I have to address this tonight. A few hours later I found myself with the left valve cover removed, and playing won the the slack in the main chain. Even knowing that there was no oil pressure currently, I was sure that replacing the tensioner would resolve my problem. It had worked for everyone on the internet, though oddly theirs was always on the right bank. I called work, told them that I wasn't going to be in to more, called and ordered tensioners for left and right sides ( since I was going to have the cover off anyway ). I began where I left off early the next morning. Fan and shroud, gone. Radiator gone. The thousand miles of tubing and short hose connections, removed. Water pump......WTF, this pulley is WAY sloppy. Observed location and design of pump.....starting to think I found my noise. Pump removed. Pink crystals caked up on engine around water pump. I wish I could have seen them form just looking under the hood. Here's the long and short of it. If you have ever had to replace the pump on your Tundra, you know the location and design would resonate the sound of a bad impeller shaft directly to the valve cover of the left bank exactly where the timing chain is. The water pump in its self wasn't bad, but to have to put the left valve cover back together for an unnecessary reason. We'll that's just a painful life lesson. You Tube, forums, and the rest of the net is good, but beware. Just as all symptoms lead to cancer on WebMd, you have to take everything with a grain of salt. Anyhow....the noise is gone.