How to Replace Gen II Prius Spark Plugs and PCV Valve

I did this yesterday at just over 122k miles. The old PCV valve wouldn't budge so I took a second wrench and put it on the end of the first wrench for extra torque and that got it loose. The old plugs I didn't need that trick for although they took a lot of force to get moving. Glad I didn't have to remove the wipers/cowl. I used NGK iridium plugs so I didn't use any anti sieze. The old plugs were also NGK.

It was hot outside which made it unpleasant work, if it were a nice day it wouldn't be so bad to do.

 

Spark plugs are usually not an urgent thing to replace, you can always wait for good weather for that

 

Hi
I have never used socket wrenches, torque, ratch etc. I bought a Stanley Mechanics Tool set (145 pc), can this get the job done without a reversible combination rachet wrench? Also, for this job and the transmission plugs, what kind of torque wrench should I buy, they have different inches listed on them (1/4 in torque wrench etc)?

 

For the spark plugs, that toolset is more than enough.

For the PCV valve, a racheting box wrench would work better. You might also need a metal tube about a foot long that can fit over the wrench. This is because the PCV valve can be overtightened and you would need a lot of muscle to break it loose.

For the transmission plugs, when I performed this maintenance on my Prius, I just used plain muscle. No torque wrench. The two plugs that need to be removed to service the transmission aren't the type to back out over the years. But you may need a breaker bar to loosen the drain bolt. Just don't tighten them so much that you wind up stripping them.

 

For the transaxle drain and fill plugs, a 1/2" click torque wrench and 1/2" breaker bar would be best. For spark plug work, a 3/8" click torque wrench would be best.

The 1/2" and 3/8" sizes relate to the size of the socket fittings that attach to the wrench and are loosely related to the maximum torque that the wrench is intended to apply.

The 1/4" size is for delicate work where relatively low torque is required. For example, transmission or engine oil pan bolts.

 

What's the socket size for second gen spark plugs? I know on third gen it's 9/16", somewhat difficult to find.

Regarding torque wrenches, yeah: 1/2" tends to be abundant, and higher torque range. Also, a Sears sales rep * told me any torque wrench tends to be most accurate near the middle of it's range, so you don't want to use one that barely reaches some low torque value.

I'd had a (cheap) 1/2" TW for decades, finally picked up (an equally cheap) 3/8" one with better low end range. I tried them both, set to a mid-range value, setting a value like 40 lb/ft, putting them on one of the car's wheel lug nuts, and pulling with a decent digital scale, one foot from pivot point. They both clicked surprisingly close to 40.

* That was two-three years back. Going through our Sears hardware section lately, the shelves look half-bare, and it has the feel of a liquidation store.

 

Thank you! I will take this information with me to Sears or home depot.

 

I've been using a 5/8" standard spark plug socket.

Have you tried a deep socket 5/8" on a new spark plug to see how loosely it fits the socket?

 

Yes I had a 5/8", figured that's what I'd need. I was not replacing, just pulling them for a look. Going from memory I believe a 5/8" will rotate on it. Again, this is THIRD generation.

Luckily I was able to find a 9/16" deep socket within walking distance. Not a proper spark plug socket with the rubber insert. But I manage to jam one in from a 5/8".

Since then I found a nice made in China set with 9/16". They're for real.