2.7L cold start rattle?

Mine does it but not nearly as loud. 09 2.7 with 85k running mobil1 5w20. Goes away after a few minutes , been doing it since around 50k.

 

That's true didn't think about if it were timing chain it would be a constant noise. I guess we still don't have a solution to this engine racket. I will say this I did not have an engine knock in my truck until I ran seafoam through it. Think it cleaned a little too damn good.

 

So far mine hasn't done it again, I put seafoam in the tank and its been cold still monitoring

 

I havent got this, but it sure sounds like a fan clutch problem
Has anyone tried removing the fan belt at cold start ?

 

My AC pully bearing was going out. I replaced the bearing/pulley assy.

Try listening there or pulling the AC belt off...?

 

I have the same problems 2007 2.7l 87,000 miles I got my truck at 68k and just noticed the rattle this winter when it's around 25 degrees F and below. But I haven't figured out the problem yet.

 

I'm having same symptoms on 2002 2.7 4x4 132,000 miles. First start it makes the "timing slap" sound I remember from my old 94 Tacoma 4cly, BUT the sound disappears after about 30 seconds or less. . I'm glad I found this thread. I was just about to order a timing chain set. So from reading this thread, take off fan belt and/ or a/c belt to rule them out. Anything else? Thanks in advance.

 

Mine does it, seems like running premium gas makes it better. Idk why but it helps

 

I've started to hear a little of this with the recent cold turn here. When the temp is -10F or less it'll lightly rattle for 20-30 seconds. It's probably no big deal. My 4.0 rattled much worse even in the summer

 

From what my mechanic said it's something rattling in the catalytic converter, until it heats up and expands!

 

My '03 2.7L had the same noise as on the video whenever the temps got below freezing, but since the rebuilt cylinder head and change to Quaker State Defy 5W-30 synth blend the noise is gone.

The rebuilt head was installed to fix the dreaded cylinder 3 valve burn and cracked chamber (check your valve lash, folks!).

I don't know if the oil or the head cured the cold start noise. I'd been running either Mobil-1 High Mileage or Shell synth oils previously, always Toyota filters. I used QS Defy for the initial oil fill for the extra zinc/phosphorous while breaking in the new valvetrain parts.

 

Does anyone have a definite diagnosis yet? I have this same exact noise at start-up and only seems to happen when I put it in D after start-up. Once knocking it only continues for another 10-30 seconds and never does it again until the next morning. However, it does not happen every morning.

I was able to finally get a recording of the knocking noise. The audio file starts with the phone underneath the vehicle. Then about half way through I popped the hood and put the phone near the valve cover. That is when the knocking noise seem to intensify and eventually disappear. It sounded like it was coming from the engine but I cannot be certain.

Note: I started up the truck, 5 seconds later put it in D. Engaged the parking brake and began recording.

https://soundcloud.com/yotanut/toyota-knocking

2004 Tacoma | SR5 Ext Cab 4WD 2.7L w/ Auto 95,000 miles

 

That sounds exactly like typical cold piston slap, nothing to worry about. You can identify the source more closely with a $20 mechanic's stethoscope by probing the oil pan from front to rear, the valve cover, etc. until you find the loudest source.

 

my 09 did that when it gets really cold.i went to 10w/30.but it aint been cold yet,or cold for here in texas.

 

If it goes away once the engine warms up I'd say piston slap. No doubt. Nothing to worry about. It'll probably still last a long, long time. If it was lifters or anything else it would not stop once the engine warms up. As a matter of fact it would probably get worse.

It's the damn hypertuetectic pistons they all started using years and years ago. They are stronger than standard cast pistons and cheaper than forged but they have a short skirt. If the clearances aren't just right when the engine is assembled then they slap until they heat up. Obviuosly very few companies manage to get them clearanced right on the assembly line. GM sure can't.

I can't believe they are still using them after all these years.

 

It's piston slap. There is nothing else that I can think of that would make a racket like that and then just go away once the engine warms up. I've got it on an old Caddy I own that I had the engine rebuilt in back in 1996. It's been rattling ever since. I didn't do my research and had hypertuetectic pistons put in it instead of the stock cast. Sounds like a freakin' diesel when it's cold. Runs like new when hot.

 

Here is the answer as to why pistons slap. It's the same reason every manufacturer has a problem with piston slap. If hypereutectic pistons aren't clearanced with the bore just right they make noise. They need tighter tolerances because they expand less than forged or standard cast pistons. Here are a few links that explain piston technology.

https://parts.olathetoyota.com/eutectic-hypo-hyper-pistons.html
http://www.enginebuildermag.com/2005/06/performance-pistons/
http://www.probeindustries.com/Articles.asp?ID=144
http://webpages.charter.net/beckracing/page11.htm

 

I had a valve that was way out of spec on my old 3rz taco. During late fall and early winter it would tick on start up then quiet down at not. Once the really cold months came it got loud- I mean really loud- sounded like,something was in one of cylinders. At that time the truck had 150k on the odometer. I adjusted the valves and it fixed the noise completly.

 

mine did it this morning for just a little bit.it really sounds like a rod knock or wrist pin tap.it wasn't that cold either.an old mechanic told me it will either go away or hang a rod outta the block.mine just turned 150K.and its been babied all the time.im not a hard driver.

 

I've heard in colder temps you need to use 0/20 synthetic; something about oil flow through the VVT screen. I could be misinformed but my truck doesn't rattle on cold start up.