PCV replacement how-to with photos

well, we promised that if nobody had done a PCV replacement guide before we did ours, we'd write up a photo how-to. our prius is nearing 60k miles and DH is finally home from school for a few weeks, it was a good time to do some maintenance.

you will need:
new PCV
10 mm socket
14 mm socket (just for the wipers)
adjustable wrench (for PCV)- DH didn't measure the size of the valve.


new part:


step 1
remove clips in corners of wiper cowlings






sometimes the rubber stoppers at the end come out, so note how they sit.

next is removing the wipers. this is best done on a somewhat dirty car so that the wipers leave a bit of a dusty mark on the windshield. this makes it easier to line them up when you replace them.

the passenger wiper comes off with 2 nuts:


wiggle it to pop it free, and you have


the driver's wiper is next, first use a screwdriver to pop off the cover for the nut:


remove the nut. it's advised to hold the wiper arm so you don't twist the assembly:


push and pull on the hinge where the wiper folds up to remove this:


there are 3 clips on each side of the cowling that need to be disengaged. see where DH's finger is, there is that indentation- those are the locations of the clips.


this will pull out. separate the 2 halves where it splits, but don't pull away the gasket from the plastic.

once that's gone, you have this:


unplug the wiring harness and unclip it.


remove the 5 bolts from the wiper drive assy. all 5 bolts have big washers and rubber bushings.


and it just pulls right out:


next is the relay box- 2 bolts


and it's off


reach in behind the clips that hold that relay box wiring in place, and push them out with a needle nose pliers. don't unfasten them from around the wiring harness, it's easier to break them doing this. DH did because he knows how to keep them from breaking.

pull the harness out of your way like so:


next is the drain pan. 3 bolts in the center on the bottom, 2 on each end. 7 total.




and the pan also pulls right out. it may be stuck a little, so you might need to wiggle it a bit.


now here is our uncovered engine


see this L-shaped wiring harness guide DH is ratcheting on? there are 3 silver bolts on this that need to come out. one at each end of the L, and one at the bend.


lift up the bend of the L, and underneath is the PCV.
be careful how hard you pull up, the coil wires will limit how far you can pull it up.


the hose comes off, just a finger clamp.


get a box end wrench on that thing and it'll come right out.


old and new
the new one didn't come with thread sealer on it.


replacement installed: current time at job is 13 minutes
don't forget to put the hose back!


now to put it all back together:

replace the 3 silver bolts, make sure the metal bracket is in place on the one behind the oil cap. get all 3 started by hand before taking a wrench to them.


replace the drain pan. set it back in place, start all 7 bolts by hand, line up the dust prints of the washers (start with the middle 3) so that you get the best gasket seal back.


replace the clips for the relay box wiring harness.

replace relay box


replace wiper drive assy. set it in place, start all 5 bolts by hand before tightening. plug the wiring harness back in and reattach its clip to the drain pan.




replace the plastic cowl. when lining back up, make sure the plastic tabs (like the one over DH's finger) go under the edge of the windshield glass.

to replace without tearing the seal, overlap the two halves. rotate the pieces so that they form a "v" facing you. guide everything into place.


lining everything up:
be patient if it doesn't line up right the first try, it can be tricky.


and it's right when it looks like this:


pull the center pin of the clip up to replace them, push them in to lock into place.


replace the wipers by lining up the wiper with the dust line on the windshield. once it's lined up, try to seat the spline so it's lined up the same way as when you took it off. replace the nuts- and the cover on the driver's side wiper.

you're done! DH's time, explaining and allowing me to take pictures and such, was 27 minutes.

our PCV was replaced at 58008 miles, and still sounded like new. it's cheap insurance to replace these every 60k or so.

Wow, thank you.

Um, so what would it generally cost to just have a Toyo mechanic do it? :blink:

Hi Rae,

Remember your not being charged mechanic time, but shop time. And well, you know the governemnt wants it property tax, and the gas company wants their Natural Gas paid for, and the owner wants some profit too, and so on....

you could probably expect about a half hour labor charge for the job. that's $45-50 depending on shop rates in your area.

Thank you for the fine post. I bought the PCV valve at Longo around 70K miles. Now the 05 prius has 105K miles. I have bookmarked this page and will attempt the swap on a day off soon, thank you again.

Question. Does all this have to be done when the spark plugs are replaced too? (just had em replaced at 104K miles)

Muchas Gracias from Sunny (soon to be soggy) Southern California. Merry Christmas to you.

PS, how do I nominate your post for some kind of a reward,- moderators???:mod:
here's a shot of the same part

no need to replace the PCV when you replace the plugs. they are independent of each other.

yep, the strut tops are exposed when you remove all the cowling. i thought to take pictures a little too late. oh well, strut tops are strut tops

Thanks! These types of blogs are very helpful. It is a bookmark for me.

Great photos and explanations. May I suggest that the PCV hoses should be removed and cleaned using brake parts cleaner. One hose will not need cleaning (since it provides fresh air to the valve cover) while the other will contain substantial HC deposits (since it carries the HC from the crankcase that flow into the valve cover area).

hey Patrick,
brake cleaner and rubber are incompatible. there may be some deposits, but unless it's clogged (in which case, the PCV itself will also be sticky) there isn't too much of an issue.

This is going to come in very handy, Galaxee. Thank you!

Hi, all,

Just a quick note regard'g galaxee's comment in post #1 about start'g with a dirty windshield to help you re-align the windshield wipers when you re-install them. You shouldn't need to have a dirty windshield to get them re-aligned right because if you look in the black area of the windshield near the tips of the wipers, you should see a little clear dot about 1/8 of an inch in diameter near each wiper tip in the parked position. I think they were designed as a re-alignment aid.

Ken (in Bolton,Ct)

D@mn that's a lot of work to replace a stupid PCV valve! I'm used to it being a 5 minute job, but I guess they can't make everything easily accessible. If I take another rock in the windshield I'll keep this in mind as I had to take off half the stuff in the photos for the repair guy to access the glass.

If it took your DH 27 minutes I'm guessing shop rate would be something like 2 hrs

Just out of curiosity, has your DH worked on any Prii that came in with a plugged PCV valve and what were the major symptoms?

Hi Galaxee,

I looked at the warnings printed on the brake cleaner spray can, and it says to protect paint and rubber brake parts from overspray, so I accept your comment. Perhaps it would be better to use gasoline, kerosene, or paint thinner to clean the PCV hose.

However I've seen mechanics liberally spray brake parts (including the drum brake wheel cylinder that has rubber seals) with brake cleaner fluid, without apparent concern for rubber parts or not.

When I replaced the PCV valve on my 2001 at ~60K miles I noticed that although the old valve would rattle it seemed to have deposits built up within, based upon the muted nature of the rattling. Perhaps that is why I noticed more deposits in the hose than you might think normal.

nope, he has never seen one of the new types of the valve (like the one in the prius) actually plugged up in ANY car. the older ones, yes. a normal symptom of a plugged pcv is leaking oil seals everywhere. plus black smoke from the exhaust. if the hose is pierced and leaking air, the engine will run rough and probably set MAF codes.

if the hose is of concern to you, it's pretty cheap and easy to just replace the hose too.

those rubber parts are dust covers, not pressure bearing seals. that's standard practice, to liberally spray like that.

the classic has always had more problems with oil entering the intake than the 2g prius. DH always thought that oil probably came from the pcv.

he has never seen a plugged PCV hose, but has seen deposits on them. it happens, that's pretty normal. he has replaced PCV hoses because they do dry rot. sometimes they soften due to oil exposure, but that's rare because it's supposed to be an oil-tolerant hose.

I changed the PCV valve on my 2004 today, at 70.4K miles. The rattle sound of the old valve is pretty similar to the new valve, so I would venture to say the valve installed in 2G is good for ~100K miles.

I'd like to list a few torque specs for the various fasteners involved:

80 in.-lb for the three bolts securing the wiring harness cover
74 in.-lb for the two bolts securing engine room relay block #2
57 in.-lb for the seven bolts securing the cowl to the body
49 in.-lb for the five bolts securing the windshield wiper motor assy to the cowl
16 ft.-lb for the three windshield wiper arm nuts

There is no torque spec for the PCV valve, so I suggest around 25-30 ft.-lb. My old valve did not have thread sealer on it, and I did not use thread sealer on the new valve.

I suggest removing the wiring harness connectors to the spark igniters and the fuel injectors as needed to provide sufficient slack on the wiring harness.

It was easier to replace the PCV valve in my 2004 than my 2001 because the wiring harness on the 2004 is easier to get out of the way. At the 90 degree bend, the 2001 wiring harness has cabling running down to the transaxle area and I could not figure out how to remove those cable connectors without damaging them.

I also cleaned the throttle body and throttle plate for the first time today, and would say there's much less black soot compared to the accumulation on my 2001 at a similar odometer reading.

I expected the plastic clips at the ends of the cowl tops to break due to the vehicle age, and my expectation was realized. I bought replacement clips, but the new clips are one-piece, unlike the two-piece construction of the original clips.

1st photo of new PCV valve after installation.
2nd photo of throttle body interior, not too sooty.
3rd photo of engine compartment in disarray, to gain access to the PCV valve and throttle body interior.

Hi Patrick,
Did you post the replacement process for the PCV valve on your 2001 CLassic anywhere?
Thanks,
Ed

Hi Ed,

I did not. The process is essentially the same except that Classic has two screws holding the plastic cowl pieces down instead of plastic clips; and the Classic engine wiring harness is harder to get out of the way as mentioned in my prior post above. If you can remove those wiring connectors, then you'll have plenty of service clearance. If not, then it will be more difficult.

In my case, I ended up removing the valve cover (because I wanted to look at the valve train and measure valve clearances anyway) and then replaced the PCV valve once the cover was off the engine.

Toyota recommends PCV replacement every 15K (the maintenance sheet that my dealer sent). Is this really true? I replaced mine @ 30K and now it is getting close to 45K. Please share your thoughts.