VVT Oil Filter? Poor MPG'S?

Hi all,
Been laid up and was reading my Haynes manual for my Prius cover to cover and under engine rebuild there's a good discussion on the Variable Valve Timing System Oil control valve and its "oil filter."

There's a separate little oil filter mounted on the front of the engine that apparently has a cartridge that needs to be cleaned and an O-Ring that must be replaced every time you clean it.I have never seen that oil filter discussed here before. And I was unaware of it myself.

It has a good explanation on the VVT operation and how it uses engine oil pressure driving the oil flow through this filter to either advance up to 21 degree's or retard the cam timing by using oil pressure against the vanes on a cam actuator. Good clean oil flow is important here.
My point of the post here is maybe this filter is getting clogged on older Gens or Prius's that are not well oil maintained and is causing poor timing advance leading to poor fuel economy that so many
have complained about here. Unexplained poor fuel economy posts.
My Haynes says it will affect fuel economy if not maintained.

My car is at the bodyshop so I have been unable to look at the exact locale on the motor of this filter but my Haynes says its mounted on the front of the engine and in the picture its right next to an engine mount torsion bar. Little metal can about 3 inches long with a 2 conductor electrical connector on the end of it. Looks like one nut holds the whole can on.

I will check that filter out when I get my car back. My manual says you must replace the O-Ring seal everytime you service it.

 

Hi Patrick,
Thanks for the diagram and its the "Camshaft Oil Control Valve" on the upper right of the diagram. Apparently that is an oil filter there
in addition to the valve. At least thats what my books says. Long discussion on it. Its the valve and oil filter all in one. Its serviceable according to my Haynes and requires and O-Ring. And it also says its on all models. Here's a pic of the illustration:

 

Wish I had a scanner but here's a quote from the Haynes VVT System troubleshooting page:

"#8--The first check of the VVT system components begin with removing the oil control valve filter from the cylinder head and checking the filter/O Ring for clogging ( see illustration--the one I posted). Clean and reinstall the filter with a new O-ring. A clogged filter screen is often the cause of system problems."

Interesting isn't it? I could see a partially clogged filter not allowing enough oil to achieve 100% proper spark advance which would cause poor fuel economy but not bad enough to throw a code. It does say issues with this valve will throw codes but that may be no advance at all.

When I get my car back I will pop that valve out and look at it. I'm lucky in that my Toy dealer is only a mile away so getting a new O-Ring will be no issue. I'd like to see if there is actually a filter in there. I bet there is. I just thought it odd I have never seen it discussed here before..

I will report back.

 

Very cool Patrick and that is the filter in question but that photo area looks like its really not part of the valve assy as my Haynes says but in a different area?

That area looks nothing like my photo/valve area.

Is there a better description of that engine area where that filter actually is?

 

Thanks alot Patrick. I see the intake holes there in your diagram
for referencing. When I get my car back I'll pull it out and see how it looks. It may just need to be serviced as freq. as oil changes especially if its a very fine micron filter.

And again...I wonder if this is why we see so many older car poor mpg reports. If it was partially clogged it would not allow proper advancing. Or at the least would not advance the timing as quickly.
Making for a much less responsive motor. The driver would probably not notice the less than optimum engine performance and would push harder on the gas pedal to go making the mg's work much harder causing more traction battery use causing more engine re-charge run time and less mpg's. Not to mention poor fuel combustion
to begin with. A driver may never notice it as a slightly retarded motor just has no pick up. No pinging just poor pickup and fuel waste.

 

Hi Patrick,
Got my car back today from the body shop. New front bumper cover and mounting bracket. New rear bumper cover,main bumper bracket,styrofoam bumper protector, and 2 new bumper mounts. $2300.

And I clearly see the hex head bolt right under the valve as you instructed. My back is bad today but as soon as I feel better I will pull that filter out and have a look and post some pictures of its cleanliness. I am mostly interested in how fine this filter is. Thanks for your help!!

 

Thanks dude...

 

Hi Jimbo,

Of course I'm aware of the 12 volt aux batt issue. I have seen hundreds of posts concerning that over the last 3 years I have been a member.

I'm not on a search persay about mpg issues I was just posting this filter as a new maintenance issue I have never seen before or even seen mentioned (at least by me) here on Chat ,which if never maintained (removed and cleaned and new o ring installed) by an older gen, especially one poorly maintained with dino oil could possibly lead to an unknown drivability issue and or mysterious loss of economy.

My car is a good baseline check for that filter as it's a 3 year low mile car and the oil has always been Mobil One synthetic and meticulously maintained. If I find crud in my VVT filter imagine whats going on with older less maintained cars. But on mine I don't expect to find any crud as I have very very snappy accelereration. The car is very quick. Poor advance would lead to poor acceleration.

But I am curious to see how fine a filter it is.

But I know I will pull that filter out at every oil change from now on no matter how clean the initial inspection is. I'm at 6-8K intervals with Mobil One 5-30 right now with factory filter.

 

Hi Andy,
Exactly my thoughts!! I'm out of action right now but will pull it asap. Thanks!!