Help, lost air cap

Yes it keeps the valve clean. You can buy a set at any Auto Parts store,WallMart etc.

 

I suppose if you don't mind changing valves when you foul them up with road gunk, then no. But, you won't die if you don't have one until you go to your local gas station or auto parts place and eek out a buck for a set of them.

 

Unless you're one of those airline pilot wanna-be's, the cap you lost was black.
This means you can go to Wal*Mart and buy 4 for a dollar, back in the automotive section.
If you don't want to experience Wal-Mart in it's full glory---I mean it's winter, so most of the entertainment value in what people wear to their local Wal-Mart is attenuated somewhat---maybe.
Anyway.....if you're too cool to frequent a Wal-Mart, they'll have valve stem caps in Pep-Boyz, Auto-Zone, K-mart, Target, etc...
I hate to break it to you, but the same $0.25 valve-stem cap that goes on my pickemuptruck will also fit the Prius.....sorry.
If you don't like black, they'll have them in some cool colors or chrome. Don't get green. If you get lime green, people will think that you put nitrogen in your tires.

Now...if you're one of those idiots that uses Nitrogen in their tires, well then you shouldn't have been messing with the cap, and you need to immediately go to the nearest Toyota dealership and pay whatever they charge you for a Nitrogen-filled-tire service and valve stem cap replacement.
It'll be less than $100---probably, but if it isn't you need to pay what they charge you.

 

The black caps are OK but the green ones will give you and extra 0.5 MPG.

 

I'll bet if you did an informal survey in a parking lot, a large % of cars are missing one or more valve stem caps. Prior to TPMS, I'd say it's not the end of the world, since the valve stems are replaced when you get new tires, but with TPMS being a (hopefully) lifetime item, and much more expensive to replace, it's worth the effort to get a replacement cap.

 

For what it's worth, I used to deliver papers, by bicycle, back in the it's-way-too-long-to-confess-and-shows-my-age-anyway time. Mind you, bicycle tires get pumped up to 40-85 lb, so they're usually running higher pressure than a Prius. But, unless one is using the really high pressure tires, they're just good old Schrader valves. Since I had to ride that darn bike every day, and flat tires are a pain at 5 in the morning, I learned, the hard way, to maintain those valves. And, yes, I delivered papers with serious amounts of snow, rain, and hail either coming down, melted and refrozen, or just plain sloppy. (Nobody calls the post when they miss a delivery, but they sure do complain about missing papers, even when there's 2 feet of snow on the street! For that, a sled and milk crate worked wonders. And you get a thumbs up from the snowplow drivers.) Valve caps are important.

There's not too much to these valves. They can be replaced with a handy little tool that fits down inside the hole. The mechanism itself is just a pin that sticks all the way through, has a little flat washer with a rubber grommet that makes the air seal, and a spring that goes between the flat washer and the very end of the pin.

The valve is not really designed to handle grit. If you do have grit in there and then you try putting air in, you've got every chance of getting some small piece of garbage onto the grommet, where it will either cut the rubber and the rubber will leak; or the dirt will just jam in there, letting the air leak out gradually. Whilst you merrily drive down the road.

TPMS is fun, but why risk fate? Finally, think about it: The valve stem on the tires more-or-less point towards the hubs of the wheel. Hence, when you're buzzing down the road at 70 or so there's a fair amount of centripetal force forcing whatever mud/slush/salt is present down into the works.

I'd keep all four valves covered, if I was you. Oh, yeah: You can tell, easily, if one is leaking. Put some spit across the end of the valve. If the spit bubbles up (and it may do it slowly), either tighten the valve or get a new one. Valve tools are a buck at a bike store, auto store, or your local Wall mart.

KBeck

 

On normal cars you don't need those pesky caps, they are only for show but on a Prius they are deliberately placed and tensioned to a specific torque to enhance the ride while achieving optimal fuel consumption. Only genuine Prius caps will do the job. You must go only to an authorised Prius dealer to purchase replacement caps and they must be fitted by a trained Prius technician only. I am saddened to see that you have removed the cap yourself and I would assume you removed other caps so you will need the other caps you have wilfully and recklessly removed and refitted reinstalled by a trained technician.

Of course all that was crap, I prefer the scull shaped caps myself for $3.00 at the auto-parts store.

 

I got the lifetime tire valve replacement package thrown in with the fabric protection treatment on my 2010 IV. When you got it flaunt it.

 

DANG!!!
I thought that was a 'V-ATP' only option....
I'm JEALOUS!!!!!

 

Darn, this wasn't on the list of guesses of what mwok's next serious problem would be. We weren't thinking far enough outside the box.

 

I can't decide whether to black hole mwok's posts, or to search out as many as possible to read the responses...

Though I gotta give him credit - this may be a question that has never been asked before, and kbeck's response was actually interesting.

 

LOL Are we REALLY talking about valve caps??? If you lose one, just take one off the car next to you in the parking lot...or some little kid's bike.

For what it's worth, I would stick with plastic over the chrome or metal caps...if you (or whoever changes your oil and checks your tires) cross thread a plastic cap, it's no big deal. If you cross thread a metal cap, it can be a royal pain to remove. I had an Infiniti that had metal caps (and Nitrogen filled tires)...it wasn't long before one of the gorillas at the dealership cross-threaded three of the caps. It was a bear getting them off without breaking the tpms stems.

 

not having the proper caps can lead to all sorts of problems described here on pc such as braking issues, traction control, mpg reduction, load noise and rattle on start up, drafty door seals, 12 volt battery death, hvac issues, etc. and they must be replaced as a set. so get to your dealer and get a new set of genuine toyota air valve caps asap! p.s., missing/incorrect valve caps have also been associated with global warming. just ask al gore. all the best!

 

What an astute and wise purchase. Did you also get gap insurance on the blinker fluid maintenance program? Best money I ever spent. :rockon:

 

I'd be sure to get either plastic or aluminum caps. The TPMS valve stems are metal (and not brass that the "old" styles were made of) and you can get some galvanic corrosion if you use something other than the base metal the stem is made of (which, I assume, is alumunum), especially this time of year with all the salt and other assorted crap on the roads! You'll know you bought the wrong caps when you try to take them off in a few months to check the tire pressure and they're stuck!

I also wouldn't want to get dirt in the valves. They're MUCH more expensive to replace than the old style!

 

They're just extra weight. Get rid of them and shed a few grams.
If you have to have them, at least go with carbon fiber caps.

 

I do have to give mwok86 credit. Of all the numerous, ambigous posts of apparent Prius problems taken to "My Medication Needs To be Adjusted" extreme, this was one of the most innovative.

I've been in Prius Chat a lot, and numerous automotive websites. And never have I seen a post where anyone freaked out about a lost tire air cap. Brilliant.

I recommend temporarily sealing the exposed valve using plumbers tape. Then using only side streets carefully driving to the dealership. Carefully explain the horrific situation you vehicle is in...ask for a price quote on a new valve cap...

If it fit's your budget, okay the replacement. It's the labor that will kill ya....

Then you might want a full diagnostic run just to make sure nothing was damaged by the loss of the cap...

 

oh you're just soooooo bad!!!!!