2008 4.0 knocking noise!

Stats:
2008 Taco TRD 4 door, 4.0 with 139k miles. Just noticed this for the first time reccently. This only happens when you first crank it and goes away after warm with no hint of this snchopated knock after warm. No other performance issues or else other than this:

https://youtu.be/JcCjvlpJRDY

WORRIED TACO DAD!!

 

Anyone?

 

piston slap I bet

 

I'm not sure what piston slap is, but sounds scary.

So an update I have noticed:

This only happens when you first crank in the morning or after sitting in the lot at work all day and not warm.

Even when cold, you don't hear the knock when I gear, only when in park or N. You also barely tap the gas while in P or N and you don't hear the knock.

So weird, truck drives perfect otherwise.

 

Sounds like bearing wear to me. Nothing unusual. Oil gets warm, then drains out of the crank while it sits, drains back from pump, etc, the clearances are a bit larger than original, and you get that knock until oil is circulated through to the crank bearings again. Piston slap is also possible, but with 100K+, it doesn't seem to be that unusual a sound. If it progresses it will hammer out the crank/piston bearing (actually an insert or sort of bushing). At some point it is time to look inside, but it doesn't sound that loud to me right now... If it doesn't quieten down, then you should get worried.

 

Sounds normal to me, possibly due to the cold start, try running thinner oil, give 0w-30 a try or 5w-30 if you currently haven't yet, piston slap sounds much worst and a bit louder, you'll know you have it when you have it. This is nothing but a cold engine trying to warm up. I wouldn't be concern with it if this noise goes away once the engine warms up. Thinner oil helps in the cold, but I don't know what temperatures are like for you, we've been sitting at 7-14°F. If where your from you don't get too cold, 5w-30 is fine.

 

It does not sound normal to me. What is the oil change history on this truck?

 

Mobile 1 synthetic religiously and on a rigid schedule since I got it with 30k miles.

 

My 2014 has 25,000 miles and sounds worse than yours, but it is most definitely the same sound. There was another thread about this same issue. I believe it is an oil circulation issue due to a bad oil pump. The criminals at ROSWELL TOYOTA in New Mexico say it is normal and refuse to do anything about it, so I guess I am going to have to find another dealership.

 

Best advise, RUN IT, If its bearing/bottom end it will let you know soon enough.
Piston slap is VERY common in newer engines.
Essentially one (or more) pistons or cyls are just slightly off tolerance and piston is "rocking" in the cylinder bore. There really isn't much more to it then than and a bit of noise. Once things heat up and expand, everybody plays nice and happy.
You notice it more with today's engine as the block castings are not as heavy as they were years ago, so noises transmit and project better.
I've had several newer Toyotas with this issue and never been a problem. I played with changing oil viscosity on an old 22re I had, never really changed anything, noise always present when cold, gone when it warms up. Ran it well over 200k with no issue before it left

 

Try adding in some Lucas Heavy oil stabilizer.

 

Piston slap. Very normal.

If a noise goes away when warm it is generally benign. Noises that get worse when warm are noises to worry about.

 

If this were a iron sleeved block, or an iron block, it wouldn't as detrimental to the block. Piston slap on these nicasil lined cylinders....it will score them. To the point were compression will be lost.

Add to it a thin viscosity oil. Just begging to compound the issue.

Pistons should never "slap" in an engine. Listen to how that sounds. Mechanical components in an engine, hitting each other, is counterintuitive to their operation.