Vacuum Hose Size Confirmation

[SuperG]

Vacuum hoses are measured in 1/16", right? I have 2 hoses needing to be replaced. First, the short hose to the TB, which I measured at 9/16" and the second hose to the intake, near the IAB, which comes from way below the engine and goes through some kind of junction, which I measured at 7/16"

Does any of this sound familiar?

 

[SHOZ123]

They are measured in mm.

 

[sdpatt]

Just take a pice of each hose to an auto parts store an get a length of bulk hose with a similar inside diameter. Since they are rubber, there is plenty of "wiggle" room. Is the short hose from the front valve cover? That would be the fresh air supply to the crankcase volume for the PCV system. It is under a very slight vacuum since it is exposed to the air upstream of the throttle plate. The longer hose sounds like the charcoal purge canister path to the higher vacuum side of the throttle plate. The junction you refer to might be the canister purge (CANP) solenoid valve.

 

[SuperG]

Thanks, Scott. Your descriptions sound like a match.

 

[SHOZ123]

To reduce the oil in the intake and carbon on the runners, plug the larger line going to the valve cover. This also give a small HP and fuel milage increase while reduceing the oil in the plug well problem along with other oil seal leaks.

 

[SuperG]

How did you plug that, SHOZ123?

 

[SHOZ123]

Those are just a plastic plug. Actually came off an older fuel filter where they were used as protective plugs. Any 3/8" vacuum plug will work.

 

[DeepPower]

To reduce the oil in the intake and carbon on the runners, plug the larger line going to the valve cover. This also give a small HP and fuel milage increase while reduceing the oil in the plug well problem along with other oil seal leaks.

I know this is an old thread, but it's an important issue.

You should not plug the line in the valve cover. Doing this can cause a pressure buildup in the crankcase and serious damage to rings and loss of oil. Instead, vent that line to the air using one of those cheap filters used in 1970's cars.

 

[msteiny]

I know this is an old thread, but it's an important issue.

You should not plug the line in the valve cover. Doing this can cause a pressure buildup in the crankcase and serious damage to rings and loss of oil. Instead, vent that line to the air using one of those cheap filters used in 1970's cars.

Agreed, you need to keep a vacuum on the engine. If not the oil loss will be from the seals and gaskets because of the increase in pressure.