Is my Prius doomed??

You might be able to snag another bolt from another location, the one on the air intake hose bracket, directly behind the passenger headlight comes to mind.

Then you can purchase another bolt from either an auto parts store or similar.

 

Flexible Magnetic Pickup Tool

^^^ worth a shot..

 

turn the car upside down and shake it

 

Buy/install new hardware and move on.

PS - Not all hardware is ferrous. Try inspection mirror, good light, another set of eyes and mechanical fingers (as required).

 

A room-mate of mine actually did that, no joke, after he accidentally dropped his cigarette lighter into the fuel tank of his motorcycle.

 

It was not a lit Zippo, I hope. That would explain the upside down and shake, of course.

 

DO NOT TEST THIS WITHOUT PROPER SAFETY EGUIPMENT.
Actually you can drop open flame into gasoline as long as gasoline container is filled to the brim and container is somewhere where fumes fill get blown away.

 

How cold does it get where you are at? A high-quality full-synthetic doesn't even gel until it's too cold to be out driving. Never needed a block heater, and it's -9 this morning.

 

Yes, liquid does not burn, it is the vapour phase.

 

And you find out if it really *is* somewhere that the fumes get blown away by dropping an open flame into the container...

 

Yes, most likely it wasn't lit at the moment he fumbled it. Besides the fact that he didn't burn himself up, another clue is that a lighter probably would've been too wide to fall through the opening with the lid open. That was a long time ago and I didn't hear the details.

 

Get one from a wrecking yard...they might not even charge for it. Might wait for some warmer weather, though.

 

I guess it's not for oil "gelling" prevention. it's for better fuel economy and lower engine wear on cold starts.

 

I can see why some would do that, but my understanding is that the block heater's primary purpose is to prevent oil gelling, which would make it nigh impossible to get the engine to start, and if you did, it'd wreck the motor by the time oil thawed enough to flow to where it's needed. From what I've read, if the oil isn't gelled, you have no worse protection at very cold temps than at warmer temps. The oil up in the engine is still doing it's job until fresh stuff from the pan arrives.

 

Colder the engine is when starting more it’s going to wear. And this is true in all temperatures lower than operating temperature. So block heater will reduce wear (and fuel consumption) in all temperatures. Above freezing help will be so small that it’s not normally used.

When oil temperature drops it thickens and that thick oil will not pump in as fast. Thick oil in bearings will heat, thin, and run out. But new oil isn’t pumped in fast enough since oil in the pan is cold and thick. And also every clearance in engine is incorrect since different components have different coefficient of heat expansion. And other things will effect also. Basically engine just isn’t designed to operate cold.

If oil gelling would be only reason to use block heater they would only be needed in -40c or -40F with 0w-XX oil.