hydraulic chain tensioner

[GJEMD]

I hear 1-2 sec rattle on start after driving for distance. Oil is at full operating temp. It seems louder if parked at slight incline. I never here it at cold start or if the engine cools down for an hour. I hear it most often when I'm on the road
and stop to gas up. I hear it more often in the summer when oil would be at higher operating temps. You can't hear it if the windows are up. I generally leave my drivers door open for start up just to listen. It seems the hydraulic chain tensioner is taking a sec to reach pressure when the oil has thinned out from temp. I use full synthetic 5W30 2010 4.6 runs like dream no oil usage. Any thoughts

 

[speedtek]

I have the exact same noise. It's only when engine is warm after a short shut down. Half hour or less I would say. Car has 5k on it. I don't remember it doing it when it was new. I would assume it has something to do with oil pressure. Also it sounds like it is from the left bank only. I also am getting a noise that I think is coming from the left fuel rail pump. As the engine RPM s accelerate so does the noise. Sounds kind of like a sewing machine. But does not always do it. I don't know. Car runs fine. Mileage is where I would consider acceptable compared to what I've read. Going to switch to full syn. And see if it makes a difference. I hate to go to the dealer for them to look at me like I'm crazy. Been down that road before.

 

[GJEMD]

I have the exact same noise. It's only when engine is warm after a short shut down. Half hour or less I would say. Car has 5k on it. I don't remember it doing it when it was new. I would assume it has something to do with oil pressure. Also it sounds like it is from the left bank only. I also am getting a noise that I think is coming from the left fuel rail pump. As the engine RPM s accelerate so does the noise. Sounds kind of like a sewing machine. But does not always do it. I don't know. Car runs fine. Mileage is where I would consider acceptable compared to what I've read. Going to switch to full syn. And see if it makes a difference. I hate to go to the dealer for them to look at me like I'm crazy. Been down that road before.

I've had my concerns documented but have been unable to reproduce the noise at the dealer. The fact is you won't ever hear it with door closed window up. It may do it on all of them. I've always started my rides with the door open just listen. I assume few owners do. I run full synthetic 5W30. I hear it more in the summer when ambient temps are 90 and higher after a 2 hr drive and restart after 30 minutes.
I suspect the oil thins out at higher operating temps and the oil might drain out of the hydraulic timing chain tensioner and on restart it takes 1-2 seconds to refill.
I never hear it at cold start or at Mod ambient temps. I have 45,000 on it and runs like new. I think synthetics have been proven to almost eliminate timing chain failure due to adhearance properties.

 

[motleyV8]

It could be the purge solenoid valve when it is active and recycling fuel vapor. They are well known to tick when operational on many cars. I believe I have heard the valve on my 2011 4.6 when the window is down and I am close to the building at the drive thru for the nice echo back effect. Great time to listen for engine noises is when you are waiting on your burger and fries LOL. Otherwise, I never hear it. It is just a light tick-tick-tick sound when it is active. This is normal. I had a 2003 Acura CL Type S several years back. The damn thing was so noisy on that car, it drove me nuts. First tried the dealer right after I bought it used, told me it was normal. Traced it down myself and made sure it was coming from the solenoid. It was, so I replaced it myself. Same damn thing...tick-tick-tick! Some cars have them in spots where they are better insulated, others...not so much.

 

[427435]

I question if it's the chain tightener. If the oil drains out when warm/hot, it will also be gone if started the next day. With cold oil, it will take even longer to refill.

I like better the thought about the purger.

 

[GJEMD]

I think I've decided it is coming from the AC compressor . Its usually when it's
around 90 out. It did it today. I then turned off the AC before starting and no noise.

 

[GJEMD]

I question if it's the chain tightener. If the oil drains out when warm/hot, it will also be gone if started the next day. With cold oil, it will take even longer to refill.

I like better the thought about the purger.

I have a sustained 2 hour drive every 2 weeks. speed between 65-80 mph.
When I stop and restart after 30 min, I get the 1-2 sec rattle. I have taken it to the dealer immediately and if I the restart after 5 min no rattle. If I wait several hours for the temp to drop no rattle. Never on cold start. I hear it most often when the ambient temps are 90 and above after this sustained drive. I run full synthetic 5w30. Something related to higher oil temp (thinner) is resulting in it draining out of the timing chain tensioner. Its clear this noise is related to oil temp. You cannot hear it unless the window or door is open when you start it in this special circumstance. It might do it universally but most owners never hear it.

This 4.6 has 46,000 miles and runs like a dream. All service has been done at the dealer