I went to change the oil, found the cover missing.

That little flap, unfortunately, is part of the entire shield. Mine is missing also. One edge of that plastic flap is just a crease in the plastic to make it into a "hinge". You can fabricate a replacement cover yourself and have it overlap the engine shield on the side where the creased plastic hinge would be, drill a couple holes and add a couple extra fasteners there. Or just leave the hole there. Or if you really want to get back to the factory experience, replace the whole engine shield. I've seen them down about the $140 range if your search.

 

That's because there is no separate part. What you're missing broke off, due to the poor hinge design. The plastic of the undercover is too thin and brittle to take the repeated flexing at that hinge point.

You could:

1. Order the replacement part, and any missing fasteners. And I'd suggest for subsequent oil changes: take the whole panel off, wash out the plastic fasteners with hot/soapy water, clear them of grit. Doing this, it'll last.

2. Cobble a replacement for the missing piece, with some flexible plastic sheet. Make it roughly the dimensions of the original, with holes to match the plastic fastener locations. Either hinge or create retainer clips at the hinge zone.

I'll attach a file with some info. Also, the Toyota Repair Manual oil change instruction. Note: it advises to remove the entire panel. Plus the two panels ahead of it, which is completely unnecessary, lol.

 

http://www.carparts.com/details/Toyota/Prius/ReplaceXL/Engine_Splash_Shield/2010/Base/4_Cyl_1-dot-8L/R-REPT310137.html

 

I'll save you the lecture on post maintenance checks, since you're already beating yourself up about it.

Deification Occurs.

Since the non-hinged, hinged cover has been the subject of ire among Prius owners for a while, and since you normally DIY your oil changes I'd be tempted to fabricate a replacement piece with a proper hinge.

If you're super anal about the under-hull fittings you can buy the splash guard listed above and modify the flap with a hinge and some pop rivets.


Me?
I'm not that anal.
Priuses are supposed to SAVE money.

I'd fab a replacement flap from HD rubber.


Good Luck!

 

Kosher Toyota products here:

SPLASH SHIELDS for 2012 Toyota Prius

 

What sucks: somewhere along the way, at one of those quick-change places you frequented: someone likely yoinked off and tossed the piece you need for a good cobble solution.

 

There have been numerous threads about that cover and it's seeming lack of quality. It's hinged life seems to have a finite timeline.
I know some members have fashioned replacements themselves. You might search to find some of their choices.

In short, you're not the first person to have problems with that cover.
It seems Toyota could of done better in building in durability.

 

Fourth gen is completely affixed with screws, comes right off, no hinge, by design. As long as the quick-change places don't chuck it anyway, that's progress.

 

I'm always amazed about the quality, brilliance and design of my Prius. I return to reality when I view that thin plastic "hinge" about to break off on my car. Wth, Toyota?

 

Toyota's stance in the Repair Manual is to remove the entire panel, plus two ahead of it lol. But the flap is there.

I've been DIY from the outset, done maybe 11 oil changes now. With the first change I used the flap, but right away decided never again, remove the whole panel.

 

I've used the flap every time. I even bend it all the way forward flat to the bottom of the car (there are holes there labeled for service use - I assume to use the plastic pins to hold it there). I love to tempt fate, I guess. Hasn't broken -yet-. Eight changes so far. Next one this spring. So far just over 70,000 km.

Hibernating in the garage, waiting for spring, and waiting for the FJ Cruiser mileage to build up a bit more, trying to keep too much mileage off each vehicle for insurance purposes.

 

Maybe clean the hinge zone and apply a strip of hockey tape to both sides. If the plastic fails having the tape in place it'll act like a hinge, continue to work.

MIght be a good excuse to remove the panel completely, gives you a chance to better inspect CV joints, check for leaks. If you've never had it off removing the push-in fasteners will be tricky; wash them out before reinstall.

Are you using trickle charging tactics with your mothballed Prius? Or just disconnect?

 

If the hinge looks about ready to fail I'll install a piano hinge. I've used them before on various devices.
I use a "Battery Tender" to keep the 12V healthy. I made my own clip lead for it using smaller clips.
But at this point we're "hijacking" this thread.

 

Hi
I changed my whole under cover for 51 dollar for 2014 prius.It matched perfectly from lexus ct200h.plz google part no:
TO1228169 if anyone missing the oil plates.