pcv valve

Before all the logging trucks completely destroyed the gravel sideroad to my hobby farm, last August I drove it out to the hobby farm to change the PCV. This was just before I sold my condo and got the house

Ah what a giant PITA that was. I took my time, walked away when I felt like taking a sledgehammer to things. Took me 3 days of careful tinkering. My PCV valve no longer rattled, it seemed pretty gunked up so I tossed it

Anybody else find deposits/oil in their PCV hose? I did, cleaned it out with solvents and let it thoroughly evaporate before reassembly

If I ever have to do the PCV in my FJ, it will be easier

 

What mileage had your old PCV valve logged?

I changed the PCV valve on my 2001 at 60K miles. The old valve rattled but the sound was muted in comparison to the new valve.

I used brake parts cleaner to clean out the PCV hoses. One hose had considerable deposit buildup within while the other was clean (which you would expect.)

 

The car had around 148,000 km when I did the work. I'm thinking the much colder winter driving environment - down to -40 - results in more moisture in the crank, more vapor in the hose, etc

That isn't too bad, considering how many miles it went. Older cars/trucks with carb's you were lucky to get 2 years before the PCV clogged, but it was a cheap and simple repair job

BTW didn't notice any difference in engine performance. Still a puddle of oil in my intake, etc

 

Here's another unsolved mystery. I presume you do your own oil changes and don't overfill?

Both my 2001 & 2004 have a thin film of oil visible through the throttle body opening, but there's no puddle or accumulation. Other posters like you see a puddle.

It seems reasonable that the oil is coming from the PCV valve hose, but why do some see a puddle while others don't?

 

Has anyone gone to the dealer and tried to get PCV replaced under emissions warranty? I can't find my warranty book right now, but I believe it is a covered item? In CA and some other states the emissions warranty is 15 /150.

Also this make a case for old school oil change intervals. The engine I suspect runs somewhat cool, quite often, not good for it and oil.

 

pcv is a maintenance item- i doubt you'll be able to get it covered under any kind of warranty.

 

Patrick

The mystery deepens. Since 2005 I have done my own oil changes, and am almost OCD about oil overfill. I have even run a couple intervals with just 3 litres, to see if that made any difference. It didn't

First time the dealer cleaned out the intake for free. Now they want $120 to do so, think I will let it pass

There doesn't seem to be any obvious detriment to engine performance or economy. I'm wondering if the bitter cold winter operating temps are resulting in more vapor in the system, more oil carryover into the intake?

jay

 

I am pretty sure the PCV is covered under emissions warranty. But I don't have my warranty book handy to verify. The PCV isn't listed as an item in the maintainance book, I don't beleve. I think, for quite a few years now, a lot of items have been covered under federal and CA emissions warranties.

 

A Yahoo Prius-2G poster sent me a .pdf of the 2007 CA Emissions Control Warranty (p. 22 of the warranty book) several days ago to address an unrelated topic. Unfortunately this scan was high-resolution and created a 4MB file, so I can't post it here. In any event, the PCV valve is not a covered item under the CA emissions control warranty.

I agree that the PCV valve is not listed on the Toyota maintenance schedule, which would lead some owners to erroneously conclude that this item has an unlimited life. A clogged PCV valve does not result in driveability issues or warning lights.

I assume that many high-mileage Prius are being driven carefree by their owners, who do not realize that oil sludge is building up quietly, much as cholesterol builds up in your blood vessels without providing advance warning prior to the first heart attack... :rip:

 

Hi Jay,

It seems reasonable that with a greater difference between ambient temp and engine temp, that more water condensation would form. From a colder start that results in looser engine tolerances, you could have more crankcase blow-by created while the engine is cold. Hence, more vapor to be handled by the PCV system.

I agree that the puddle is harmless. If it bugged you enough to take action, why not use throttle body cleaner to spray into the puddle, thinning it out, so that it will be sucked into the intake. Or, remove the throttle body assembly and clean the puddle with paper towels. This would give you a chance to thoroughly clean the black residue out of the throttle body, as Hobbit posted on his website sometime ago. You would need to buy a new throttle body gasket, which costs around $4. (I bought one but haven't used it yet.)

Regarding the question about why some people have oil puddles and others don't, here is my hypothesis: Many Prius owners strive to maximize their mpg and drive very conservatively. Hence, minimal throttle is applied.

In California, we have the concept that Prius equipped with the correct stickers can drive solo in freeway carpool lanes. In my local area, the carpool traffic may be proceeding at 75 mph while adjacent lanes are at 40 mph or less. In order to enter the carpool lane with Prius, you must apply WOT about one second before you actually need the power, and hope like heck that you are not rear-ended...

My theory is that by routinely applying WOT, this creates substantial air flow in the intake manifold that helps to suck down residual oil within.

 

I was pretty sure I saw something about the PCV valve, as I have replaced many over the years and made a mental note that, "gee this is covered." So I took time and found the warranty. It is covered under the federal emissions warranty for 8/80. Page 16 of the 2007 warranty booklet.

I have never tried to claim anything under such warranty however.

I wonder if an elbow could be put in the grommet to lead the PCV valve out to a more convenient location.

Usually I have relaced the valves only to find them slightly oily but rattling, never clogged and no rattle, so they were still likely OK.

 

OK, I went to my 2004 (covered by federal warranty) and retrieved the warranty book. Page 14 lists the "PCV valve or orifice" but does not have (8/80) next to it, so that means the warranty is 3/36. Therefore I assume that a change was made by 2007.

The PCV valve has a threaded body that screws into the valve cover, so it would not be easy to devise an extension. However you are right that it would be easier to change the valve if a suitable extension was in place.

 

Patrick

I'm thinking of doing that sort of project sometime this summer, assuming I don't get rid of the car for a new Prius. One thing I do want to do is borrow a fiber optic inspection scope from our office, to snoop around the intake manifold.

The actual job of removing the TB seems fairly straightforward, certainly easier than removing the IAC on a Vortec V8. About the only thing to watch out for is leaving anything behind in the intake, eg pieces of shop towel

The theory of motor operation, eg HOV lanes requiring frequent WOT, makes sense. Driving around the city the motor remains unthrottled or lightly throttled

In most gasoline motors, unthrottled and lightly throttled produces the highest engine vacuum. If the PCV is going to heavily draw vapors, that would be an ideal time to do so

Now that I'm thinking about it, there was a TSB on my 2000 GMC truck. The PCV was so aggressive that in certain cold climate operation, you would actually have oil consumption. The TSB called for a new PCV valve with a restrictor oriface.

That cured the oil scavenging, but created a very anoying whistle instead.

jay

 

all i do with my pcv valve is take it out and shake it, if it doesnt shake i soak it in degreaser and that usually fixes it

 

Coupla things.
.
I've got a fairly step-by-step cowl removal process here,
and this gets down in a little farther. What I *haven't* done
yet is pulled the valve cover -- Patrick, if that shot was of
yours, what if any issues did you run into pulling it? Did you
re-use the old gasketing? I'm thinking of at least having a
looksee and checking the valve clearances this year.
.
The throttle doesn't actually stay all that closed even during
gentle driving. Remember this diagram? I have a vacuum gauge,
so I see the immediate feedback from what's going on there.
And what I see is at a certain foot position, the throttle
basically whacks open, vac drops to 3 or 4 in-Hg, even down at
1200 RPM, and we stay in a high torque regimen as much as possible.
So your vacuum draft through the PCV is actually not going to
be all that high most of the time. Unless you do a lot of "B" mode.
.
And the jury is still out on whether the intake-plenum "oil" sump
is crankcase oil, or heavier fuel components falling down there
after being shot back out of the cylinder during Atkinson intake,
or a combination of both. It tends to be much cleaner than the
crankcase oil and *not* smell like it, and for the most part
just harmlessly lays there and refuses to vaporize. Crankcase
overfills may exacerbate it, but I've never used more than 3.5
US quarts and keep the oil level around 1/4" below the top
mark, and I've got a little sump too. When I swabbed it out
a while back it returned within a week or two.
.
I don't have a page up about cleaning the throttle body [just
diagnosing a "failed" one], but I think Bob or somebody else
did up some details on it. You can pull the TB and clean it
without disconnecting the coolant hoses. Remember to lube the
butterfly pivots, too.
.
_H*

 

Hi Hobbit,

Yes, that was my photo, and it is not particularly difficult to remove the valve cover after the cowl is removed. You have to disconnect the spark igniters and fuel injectors from the wire harness, unbolt the wire harness from the valve cover and move it out of the way, and remove the spark igniters from the valve cover.

I bought a new valve cover gasket as well as a tube of Toyota black FIPG. I posted several photos of the operation in Yahoo PTS group when I checked my 2001 valve clearances last summer.

The valve cover gasket is made of black rubber and is extremely high quality. It potentially could be reused. However I hate engine oil leaks and a new gasket is not expensive. The top of the gasket has a ridge that fits into the valve cover, thus holding the gasket securely in place. FIPG is used to place a couple of dabs where the head attaches to the front engine cover, which also is where the camshaft pulleys are spinning and presumably spraying oil around.

Thanks for your comments about the pool of unidentified hydrocarbons. I suppose it will remain a mystery as to exactly what it is and why some but not all can see it in their vehicles.

 

if it's listed, it is covered if it fails- not as regular maintenance. just because it's not listed in the maintenance booklet does not mean it is never needed.

 

hobbit- you know better than to reuse a vcg. if you're taking the cover off, redo that seal tightly. with a new gasket.

 

Absolutely, plus its cheap - MSRP is $15.49; web discounted price is $11.77 at Champion Toyota Gulf Freeway (Houston).

On my prior msg I posted a couple photos of the 2001 valve train with the old valve gasket still in place, so you can see what the gasket looks like.

 

my new friend, i have seen more disassembled engines than most.

imo a pretty vcg is one that doesn't leak!