I went to AZ to find a replacement, no luck. I went to O'Reilly and I found what I thought was a replacement, PN 47150. I'm not sure if it is working correctly. The stock doesn't allow any pressurized air through and the replacement does. I think it is defective. The replacement one doesn't just blow pressurized air directly, it does build some pressure, but it does bleed down to zero. Probably not the way it is supposed too work.
Broke HVAC Two Way Check Valve
- Thread starter MCH86GN
- Start date
Welcome!
By registering with us, you'll be able to discuss, share and private message with other members of our community.
- Joined
- Aug 1, 2003
- Messages
- 9,610
the 47150 is the correct part
the 3 port should act as a check
the " source" port at bottom can allow vac but wont allow pressure
the other top ports ( at top and side ) are shared and one at side goes to the vacuum reservior ball under driver wheelhouse
the other to the hvac control in the dash
if you block one of the top ports you should be able to pull and hold vacuum from the other top port
there is also another check valve upstreap of the hvac check , its white and black and inline before the egr solenoid to protect the egr solenoid from damage from boost , it also helps to protect the hvac valve
try highwaystars for the other check valve
the 3 port should act as a check
the " source" port at bottom can allow vac but wont allow pressure
the other top ports ( at top and side ) are shared and one at side goes to the vacuum reservior ball under driver wheelhouse
the other to the hvac control in the dash
if you block one of the top ports you should be able to pull and hold vacuum from the other top port
there is also another check valve upstreap of the hvac check , its white and black and inline before the egr solenoid to protect the egr solenoid from damage from boost , it also helps to protect the hvac valve
try highwaystars for the other check valve
So at the source port when I pressurize, as if it is under boost, no air should be coming out of the other two ports correct?
- Joined
- Aug 1, 2003
- Messages
- 9,610
correct
I'll get a replacement. Unfortunately, the AZ I was didn't carry it and the O'Reilly's only had the one and I checked it, figuring it was broken but bought just in case I need to drive my car. Obviously I won't boost it.
One other question, there is what appears to be a check valve that is connected to the same vacuum line that is connected to the 2 way check valve. Should it be there and is it a check valve, if so its not functional. I can provide a picture if need be. My EGR is deleted.
Thanks.
The check valve upstream of the HVAC doesn't work either. Since I deleted the EGR I can probably delete that check valve, however, it is nice to have an added measure of safety should the two way fail.
Also when I pulled the lines off the vacuum block and hooked up my mity-vac I wasn't able to pull any vacuum for the HVAC and the vacuum reservoir ball, unlike all the others. First of all should it hold vacuum? If so, I have a sneaking suspension that the HVAC in the dash has a vacuum leak. I'm not able to control what vents my air blows out of .
Sorry, I didn't realize that you had already answered this question.
"One other question, there is what appears to be a check valve that is connected to the same vacuum line that is connected to the 2 way check valve. Should it be there and is it a check valve, if so its not functional. I can provide a picture if need be. My EGR is deleted."
Also when I pulled the lines off the vacuum block and hooked up my mity-vac I wasn't able to pull any vacuum for the HVAC and the vacuum reservoir ball, unlike all the others. First of all should it hold vacuum? If so, I have a sneaking suspension that the HVAC in the dash has a vacuum leak. I'm not able to control what vents my air blows out of .
Sorry, I didn't realize that you had already answered this question.
"One other question, there is what appears to be a check valve that is connected to the same vacuum line that is connected to the 2 way check valve. Should it be there and is it a check valve, if so its not functional. I can provide a picture if need be. My EGR is deleted."
Last edited:
- Joined
- Aug 1, 2003
- Messages
- 9,610
if boost goes through the hvac line it can pop the multi switch in the dashboard hvac controller
that switch is replaceble
that switch is replaceble
I bought a new two way check valve and it works. I individually checked the the two vacuum lines that connect to the two way and neither will hold vacuum. I'm going to assume that is an issue and I need to find where the leaks are off of the two vacuum lines.
I also bought an AZ 1162 PCV. I'm currently running an RJC PCV and my BLM stays at 142, even with the two ports capped off on the two check valve to temporary fix the what I think is a leak.. So I'm going to put the stock PCV in and see if that improves the BLM and if it does, then I'll try them in series.
What the hell is the purpose of this thing?
- Joined
- Aug 1, 2003
- Messages
- 9,610
to provide vacuum at all times even during wot to operate and hold the diaphragm doors of the hvac and vents so they direct air as needed
Dumb question, but when you put a mity-vac on the vacuum line of the vacuum reservoir ball, if you pull a vacuum should it hold? Mine doesn't. This is with the car off. I'm going to play around with it, while the car is on and see if I get different result by placing a t in the line so I can hook up the mity vacuum. I'm glad I bought it. Also, as I mentioned, I have a vacuum leak where the vacuum lines connect to HVAC. I can hear it when the car is running. Hopefully, I can figure out where it's leaking.
Got to have all the vacuum leaks fixed before I drop in my rebuilt 109 block.
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
- Messages
- 6,110
It's a vacuum ball so yes it should hold vacuum. BUT, it takes a while to actually start building a vacuum on that ball. You gotta keep squeezing over and over until it builds up. Don't just squeeze it a few times and say screw it. Keep trying. Check to see your connection isn't leaking either.
- Joined
- Aug 1, 2003
- Messages
- 9,610
after engine runs and is off let it sit awhile , if you pull the line from the hvac check to the vac ball and you hear the vacuum rush in .. the check valve is operational and you have no leaks in the hvac lines or controller
if no vacuum present you aren't done.. find the leak(s)
if no vacuum present you aren't done.. find the leak(s)
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
- Messages
- 6,110
That's another way of doin' it, yea.
I know I have a leak in my HVAC, when the car is running and I put my head close enough I can hear the sound of air sucking. I need to fix that.
Per your suggestion, I will pull the vacuum line of the two way check valve and hook my mity-vac up to that single vacuum line and do as you suggested. I'm going to have to pull off my HVAC controller while the car is running and see if I can localize the where the leak is.
Once I get my motor out and before I drop my rebuilt one in, I'm going to replace the vacuum lines.
It isn't leaking, I took the vacuum line off the two way check valve and I had to squeeze it around 10 times before noticed the need moving and I finally got it to -20hg and left it there for about 20 minutes and I didn't see any leaking. Should have been intuitive that it would take a number of squeezes to pull out all the air in the vac ball considering it was probably at atmospheric pressure.
