5.0 Thunderbolt does it have a pcv valve or is it hollow?

[Bignev2]

Hi,

I'm just going through the engine and replacing alot of stuff for maintenance.

According to mercury parts the 5.0 tks does have a pcv valve 21-8M2017060
but some posts i have been reading say the older carby's dont have pcv valves
the elbow and valve is hollow ?

If it does how often should it be changed ?

Engine serial is : 0l023213

Thanks

 

[Rick Stephens]

Just a breather, no valve.

 

[Bignev2]

Just a breather, no valve.

No worries bit confusing cause mercruiser lists it as a pcv valve haha.
Thanks

 

[alldodge]

Agree, it shows 2 PCV valves on the motor. One to carb and other to flame arrestor. Don't get why there would be one to the flame arrestor because there is no vacuum. Either way I would probably never replace them unless you start seeing oil building up on top the motor.

 

[Bignev2]

Agree, it shows 2 PCV valves on the motor. One to carb and other to flame arrestor. Don't get why there would be one to the flame arrestor because there is no vacuum. Either way I would probably never replace them unless you start seeing oil building up on top the motor.

Yeah that's why I wasn't sure but all good.
Got the boat a year ago and just going through the boat replacing things done the plugs,rotor,cap,coil, engine oil and filter, leg oil runs pretty good. Just got a timing gun and impeller kit.

 

[sdowney717]

This 1984 350GM motor with thunderbolt ignition has no PCV valve that I noticed.
It does have 2 breather hoses from valve cover to the top carb cover

 

[sdowney717]

without the flame arrester cover. I had to rebuild the carb, no vacuum port on it for a PCV. Nothing noted on the manifold. The things that look like PCV on the valve covers are just empty PCV like shells having no internal valves.