4.0L V6 Cold Start Engine Knock, Noise, Possible Cause ???

I've seen more threads lately on this issue along with the older threads over this problem. It's been suggested the culprit is a bad oil pump, but haven't heard of anyone changing it out and curing the knock.
Has anyone given any thought that the noise could be coming from the crankshaft pulley, harmonic balancer ?? These can go bad, come apart wear out or be bad, out of balance from the start when new. Just thinking out loud for a possible remedy ?

Thoughts ?

 

Put your ear to the cab floor behind the drivers seat. Hear it clearly? Mine seemed to be coming from the fuel hard lines under the cab leading me to suspect the fuel pulsation damper was the culprit. It drove me mad, on a cold start the truck sounded awful. A loud metallic rattle dependant on rpm which changed tone to a deep knock when at idle in gear. Once at full operating temp the truck was quiet, id faintley hear the metallic rattle at times but nothing close to when it was cold.

What's odd is mine was a 2006 V6, the 2006 I4 had a recall for noisey fuel lines. What drove me mad was it developed the noise at 180,000km and sounded worse each consecutive winter. In warmer weather I'd rarely hear it.

More maddening was having every tech ignore me because so many people complained about the normal vsv/valve train/injector noise. I'm fairly mechanically savvy, I checked every obvious part beyond tearing the engine down. I spent hours with my stethoscope.. nothing. Piston slap, a broken catalyst, cracked flexplate or FPD were as far as I narrowed it down.

 

This has been happening to my truck for the last 6 years or so. It used to concern me but every year that goes by I worry less about it. Sitting at 120k miles and going strong. No worries.

 

Can you post a clip of the noise?

 

Mine sounds like a conveyor belt with tiny hammers pounding on that shit but I just warmed it up for a few minutes and drive it like I stole it.

 

Ive been having the same issue. Drives me nuts. Cant hear it under the truck or under the hood. Just from the cab. I only hear it when its cold. Sound about right?

 

Could you be using a cheap oil filter that has cheap and poorly designed bypass valve and/or drainback valve? Such as SuperTech, Bosch, or AC Delco?

 

That's the issue, only when cold. This is the second winter mine has done it, sitting at 128,000 now.

 

Second winter for me too 130k.

I use a Fram TG.

 

Nope,

$54 90915-YZZD3 Oil Filter 1 Case (QTY 10)

90915-YZZD3 Toyota filters with Mobil 1 5W30 Synthetic and changing both at 4000. I've only used 2 or 3 Fram filters in it's life

 

It's probably still breaking in, the noise should go away around 300k miles.

 

But on a serious note, I have an issue of where my truck sounds like it has an exhaust leak right after I get an oil change. Then it goes away after about 5 miles. I drove myself nuts trying to pin point every single engine noise on my last car and it lasted a bunch of miles. It ran like shit new and it ran like shit 80k miles later, but it made a bunch of weird noises along the way. Then I thought about how many moving parts, pumps, valves, actuators, injectors, evap, etc. and shit are on that engine to make it run normally. It has to make some weird ass noises once in a while.

 

Yup same here. 2009 4.0 and its done it every winter since 1 year old. Only hear it in the cab. I use stock oil filter Mobil and or Castrol. Doesnt make a difference. Sounds like a metallic tick or exhaust leak. Goes away in a few minutes of driving. Cant figure it out. Was thinking it has something to do with the fuel lines pulsating. It changes tone as the engine warms up depending on fuel pulses me thinks. Anyone else have any ideas?

 

The sound most are referring to is more of a deep knock, not a tick. It only seems to be present when the temperature is below about 40 degrees and gets worse in extreme cold, below zero.

 

Was sort of replying to post #2 & 6. Similar symptoms. Thanks for the heads up.

 

I have a knocking/rattling sound that I notice more when I'm idle. I'm in a standard, and when my clutch is in the sound changes. It disappears right as I begin to creep forward, then returns when my clutch is fully out. It happens in all temps and I'm only at 35k miles.

 

Mine just make noise all the time

 

Upon further inspection, mine definetly dulls out after warming up. Still don't know what it is. Sounds like it's coming from the cat converter, but I can't really tell. My hearing sucks.

 

Take a long screwdriver or some and start setting it on parts and listen to the other end till you find the loudest noise.