Hose from block to manifold

[dennis]

What is the hose from the intake manifold to the block? Mine cracked and I have a vacuum leak of course. Can I just plug the hole or are both ends used for some kind of circulation? I plugged the hole on the manifold with a rag and the L16 runs like a champ.

 

Here is a pic (oh its the tube behind the one with the vacuum cap)

 

[INDY510]

The bigger red circle is the crank-case breather.... (I think)

 

 

DO NOT plug the crank-case breather tube

[dennis]

The bigger red circle is the crank-case breather.... (I think)

 

 

DO NOT plug the crank-case breather tube

 

So I can just leave it open to atmosphere and plug the manifold?

 

If so do you know the thread size?

[datzenmike]

You don't really have a vacuum leak. The small circle is the PCV valve. It has a small opening that allows intake vacuum to draw fumes from the block vent hose. (big circle) There should be a hose connecting the two but if it is missing it won't change the engine running as the PCV valve is drawing air in all the time anyway. The PCV valve opening is very small and the motor is set to run with this very minor 'leak'. There is a one way valve with a spring in it to prevent a possible back fire from traveling back into the crank case and possibly igniting any oil or gas fumes.

 

Find or get a hose or some home made set up to get this hooked up. Although this could be considered an emissions thing, the PCV valve actually removes water vapor, fuel and oil fumes from the inside of the motor that would otherwise condense when the engine cool. Water and fuel would mix with the engine oil and dilute it. This will reduce it's lubricating qualities and so will require changing more often. The PCV system is benign in operation and has NO effect on running other than keeping the engine oil cleaner. Oh yeah, it also prevents unburned hydrocarbons from escaping into the atmosphere. (but I like that it keeps the engine cleaner)

[dennis]

You don't really have a vacuum leak. The small circle is the PCV valve. It has a small opening that allows intake vacuum to draw fumes from the block vent hose. (big circle) There should be a hose connecting the two but if it is missing it won't change the engine running as the PCV valve is drawing air in all the time anyway. The PCV valve opening is very small and the motor is set to run with this very minor 'leak'. There is a one way valve with a spring in it to prevent a possible back fire from traveling back into the crank case and possibly igniting any oil or gas fumes.

 

Find or get a hose or some home made set up to get this hooked up. Although this could be considered an emissions thing, the PCV valve actually removes water vapor, fuel and oil fumes from the inside of the motor that would otherwise condense when the engine cool. Water and fuel would mix with the engine oil and dilute it. This will reduce it's lubricating qualities and so will require changing more often. The PCV system is benign in operation and has NO effect on running other than keeping the engine oil cleaner. Oh yeah, it also prevents unburned hydrocarbons from escaping into the atmosphere. (but I like that it keeps the engine cleaner)

 

Thanks mike

[datzenmike]

If you mean unplug the hose it shouldn't matter. The PCV will just be sucking outside air instead of air from inside the motor. Maybe the hose or block vent baffle is blocked. Also the hose from the valve cover must be clear to let air into the motor to replace that taken out.

[dennis]

If you mean unplug the hose it shouldn't matter. The PCV will just be sucking outside air instead of air from inside the motor. Maybe the hose or block vent baffle is blocked. Also the hose from the valve cover must be clear to let air into the motor to replace that taken out.

 

All I know is that when I plug the PCV valve the car purs like a kitten and once I take that plug out it dies quickly.

[datzenmike]

What happens if the hose to the block is on? Just duct tape the cracks.

[dennis]

What happens if the hose to the block is on? Just duct tape the cracks.

 

Well I am not sure because this is the first time I was able to get the car running with a nice steady idle without feathering the throttle to keep it going. I changed the intake/exhaust manifold gasket today and the hose broke. I fired up the car and it died quickly. I blocked off the PCV valve and it ran great, no running rich and the idle was high so I adjusted it. I also checked for manifold leaks with my carb cleaner and I didnt find any.

[I'm BLUE]

DO NOT plug the crank-case breather tube

 

+1 for sure do not

[hang_510]

IIRC that hose is still avail from nissan

[dennis]

IIRC that hose is still avail from nissan

 

thanks, I have been looking for the part number for about an hour.

[hang_510]

PM hainz, he likely has it linked in 50 places

[datzenmike]

11828 23002 Engine hose vent to PCV L16 for 521/510/620 and L18 from 610

[hang_510]

11828 23002 Engine hose vent to PCV L16 for 521/510/620 and L18 from 610

whats the number for an L20b?

its has the longer/different angle pipe, but the OD's are the same

[dennis]

I picked one up today from Courtesy Nissan in Dallas.

[datzenmike]

whats the number for an L20b?

its has the longer/different angle pipe, but the OD's are the same

 

 

Depends on what it's out of and if using a different intake as the PCV valve is differently mounted. Some early 610s had the same piping as the L16/18 that came straight out from the block.

 

 

11828 N5800 Cali '78 620, S10 200sx and A10 (later 510)

11828 U6702 all 710 L20B

11828 05W01 '80 720

[hang_510]

:thumbup: ^probaly diff between a car and a truck as well.

 

lets see if i can find pix to go w/the ### :)

[datzenmike]

Brian I checked... the L20B in everything EXCEPT the 610 all used the same block vent pipe. So the only difference is the where the hose meets PCV and how it is mounted to the intake.