Does your Prius Prime engine makes this noise?

My prime is a bit noisey if I let it sit or run in EV mode only for more than a week. It’s probably because the oil needs to reach all the right places.

 

I have never heard such a noise. It almost sounds like a part is loose.

 

Yep, that's not normal....take the car to your dealer and if it won't make it for them, show them the video. (Preferably to a master technician, not just a service manager.)
Keep us posted!

 

I'm hearing a very loud clatter at about 0:02 in the video, and later, around 0:10, a voice saying "hear it?'.

If the question was about the clatter, it sounds so early to me, right at the start of engine cranking, that I doubt it can be explained by misfiring. Sounds like it happens before the engine even tries to fire (I'm used to it cranking a little bit first, but I've really only known gen 1, 2, and 3 up close).

I wonder if it is something like the oil leaking down from the hydraulic lash adjusters in the valve train during the time the engine's been sitting, and then quickly getting pumped back up.

 

I saw the engine actually shake a little during the clattering. Seems like minor hydrolock going on there. I think the first thing I'd do is pull the air filter and look down in the intake manifold to see how much fluid is accumulated down there. A little bit is normal, but too much and it gets sucked into the engine on start up. Not very good for the engine.

Also, you might want to have someone else start it while you watch the tail pipe for a puff of smoke.

Another thought that occurs to me is that maybe there's a slightly leaky fuel injector that lets a drop or two of gas into one of the combustion chambers. I once had a motorcycle with a carb needle that occasionally let fuel into a cylinder while the bike was off. That was some NASTY hydrolock.

I agree with the suggestion to take the video to the dealer and make sure someone who knows Gen 4 Prius engines gets a look at it.

 

Hi , I am an illiterate in engines , so I am no help for a diagnostic
so here is what i found in my user manual ...if it helps

 

Coincidentally, that idea just came up in another recent thread.

There was some older thread where I got a cross-section diagram of the engine and drew a simple picture, but right now I'm not finding that old thread (or the diagram I used for the picture). So I've drawn it again:



Keep in mind those intake manifold bores look at least a square inch in cross-section and at start-up the RPM is no more than 1000 to 1200 and the throttle is nearly closed. That's not much of a recipe for airflow to slurp some liquid half a foot upward in the manifold.

Color me skeptical on that particular explanation....

 

After giving it some more thought, I agree with you. Pretty unlikely. Otherwise, I think we'd see a lot more of this issue.

 

Have you isolated where the noise is coming from? If it's on the top/left of the engine, I'm suspecting a VVTI gear may be the cause. At 9,000 miles, the car should've had two oil changes and almost due for another. (1,000 break-in, 6,000, 11,000 miles)

 

Not a bad regimen, I agree, but for the record: not according to Toyota USA.

OP's video has a nasty rattle, at the very beginning, less than a second. Or maybe that's because I'm never standing in front with the hood up, when our (gen 3) starts??