Help identifying a part please?

It's a broken off piece of item #6 , which you can see here:

SPLASH SHIELDS for 2010 Toyota Prius

The overall piece, with the part that's broken off highlighted:



The issue: the plastic of this shield is thin and brittle. The portion that you are seeing had was "hinged", so that with removal of a couple fasteners it could be bent down, for access to the oil filter and oil pan drain bolt. The problem though, the material is too thin and brittle to act as a hinge, stresses, eventually breaks.

You can either cobble an actual hinge, or some sort of restraining lip, or spring for replacement of the complete shield. I'll attach a pdf also, that has the parts numbers for the fasteners.

If you go for the replacement, I 'd suggest to never use the flap, instead remove the entire panel, for each oil change. Also, wash the push-in fasteners out in hot, soapy water, to sluice out grit which can jam their internals.

 

What Mendel said, I bought my '10 with 43K miles and found that same part was missing. I didn't bother to replace it and now have 170K and it hasn't been a problem. If you can't manage a fix for your part, the complete cover is here for spare change compared to the dealer asking price for it. It's the 4th item down at this link.

10 2010 Toyota Prius Lower Engine Cover - Body Mechanical & Trim - Action Crash, Front, Rear - PartsGeek

 

You've got the piece. Maybe just reinstall with a pair of home-made hinge, or glue on some tabs so that it's locked in place. You might need to get a few replacement push-in-pins, or they might even be in the holes still.

Or do nothing. Still: your engine bay will get dirty faster, lose heat, and if you're in the snow belt, the opening may snag, start a cascade of other bits tearing off.

FWIW, fourth gen makes the comparable piece completely removable (no hinge), and secures it with screws instead of push-in fasteners.

 

Here's a pic of mine for reference:



The blue location requires:
90467-09227 Thicker Metal & Plastic Clips (item 5 in pdf)
Red location is the usual fastener:
90467-07201 Thin Metal & Plastic Clips (item 3 in pdf)
Green location has a plastic splice plate (far side) and pair of:
90467-07166 Plastic & Plastic Clips (item 4 in pdf)
Lime green location: for hinges or some sort of locking tabs.

The splice plate you could create yourself, out of anything, a margarine tub lid for example.

 

I'd just leave it. It does allow a -little- more dirt to get up there but I doubt you'd notice. Bonus, you have nothing to remove when it's oil/filter change time! Of course the EPA/CARB guys might be miffed as you -might- use a tiny bit more fuel.

 

You can also drill small holes that will allow small zip ties to fit through and use the zip ties as the hinge. Maybe just four.

 

Here's something I sketched up a while back, the idea being to add a couple of tabs at the broken hinge zone, just holds it in place, in concert with the push-in fasteners at the other side.

 

Might be too stiff to bend, but you remove the entire cover so not an issue. I like the piano hinge idea best. I have "pop-rivit" style thread inserts and have used them on other vehicles on the undertray. You drill a hole, pop the thread insert in, and then you can use a -proper- bolt! Just like the G4 does. What a concept!

 

It's not intended to bend, just hold the piece in place, and allow it to drop off when the pins are removed.