PCV valve test ?

[Live to Ski]

Hi gang,

I've done the search, but found no comments on the actual PCV valve test.

The emissions manual say that air should flow freely in one direction, and flow "with difficulty" in the other direction.

My valve does allow air to freely go in one direction, but will not allow "any" air in the other direction (under lung power).

So, is the valve good if air won't flow in that direction?

Thanks in advance!

 

[slcfj62]

There is a ball bearing in the valve. If you shake it and cannot hear it rattle, it is definitely bad. If it hasn't been replaced in a few years, just get a new one from Toyota and replace it as a maintenance item. They are pretty cheap. I also replaced the rubber hoses with Napa fuel line because the Toyota hoses were about a million dollars.

 

[2mbb]

Here it is from the FSM

 

[rusty_tlc]

If it fails the test spray some carb cleaner in it and cover the hole with your fingers, then shake it for a while, rinse and repeat as required. Once you get all the gunk out it will be fine.

 

[Live to Ski]

Well, I have the rattle.

I guess the question is that the reverse flow is completely blocked while the other direction is open.

The manual makes reference to the reverse flow exisiting w. difficulty.

It's the " with difficulty" versus "completly blocked" that my question addresses.

Anyone?

 

[FJ40Jim]

When the intake manifold backfires, the PCV valve should blow shut to keep from pressurizing/igniting the crankcase.

So no, there should not be any noticable flow in that direction.

 

[rusty_tlc]

Well, I have the rattle.

I guess the question is that the reverse flow is completely blocked while the other direction is open.

The manual makes reference to the reverse flow exisiting w. difficulty.

It's the " with difficulty" versus "completly blocked" that my question addresses.

Anyone?

Consider the function of the PCV valve or Positive Crankcase Ventilation valve. It's purpose to to vent fumes from the crankcase back into the intake manifold where they are burned by the engine. In reality the PCV valve is a check valve which stops air flow into the crank case. As long as you have air flow in the correct direction you are fine.

 

[Live to Ski]

That's what I thought.

Many thanks!