Vacuum check valves

When your heating or Cooling modes change on their own or fail to respond and the only thing that works is your defrost mode on Dodge trucks 8 out of 10 times if you don't have a vacuum leak you will have a bad vacuum check valve.

[@HWPcville]

I've posted this comment on other videos but hopefully it will help someone. My defroster was stuck in the on position which was due to a vacuum leak. The leak was in the small vacuum line that passes by the transmission dipstick handle. The embossed letters "TRANSMISSION" on the handle has sharp corners and over time wore a hole in the vacuum line where it touched. It was just by luck I found the leak as it was on the hidden backside of the hose. I felt it but never saw it. I taped over it and it worked again

[@waynehutchinson1423]

Thanks ot did help.Keep on taping.

[@mick5740]

great help! now i just need to figure is it a generic size or special. i have a okd good one or two from a ford. goinh to try tomorrow. my 95. had a loss of air power that elevated with engine rpm. has got worse or weaker flow. and now all the sudden im kot getting heat. but i did kot heater getting hotter when i was revving engine while i was burping the cooling system as the water pumo has just been replaced too. i did test heater after that service and it was hot at least once. mow it is winter and i need that heater working 😊

[@shawnthaxton1663]

Recently replaced a missing one on my firewall of my 98 had to get one with 1/8 nipple on both ends as someone has made a repair in past there so all was good for few days well I started having the vent issue again so I just now checked one on intake and it is shot as will be replacing it wouldn't it being bad be same as having a vacuum leak ? I thought the one I replaced had went bad again but it still only flows one way as should

[@mikeneuburger3989]

Chrysler discontinued the part from the dealer, so Dorman 47170 is your next best option.

[@badboyzgamingbadboyzgaming]

What size is it?

[@mick5740]

great help ! thanks

[@joemeza0801]

Wich direction does the check valve go?

[@dominicryan9739]

Amazing. This is the exact problem I have on my truck. Changes to defrost setting at high throttle / high load when engine vacuum is low. Hopefully this fix works for me too!

[@albertojuarez8741]

Dominic Ryan thank you for watching the video hopefully you replace the vacuum check valves and your problem went away

[@ballerforlife2036]

Dominic Ryan was this the issue?

[@mikeneuburger3989]

It’s a real pain when you’re getting on the freeway and it’s 90 degrees and you start sweating instantly. 😅

[@hansolo4946]

Same one I got , can see straight through it lol

[@blackericdenice]

I had this problem on a 96 1500 v6.

[@ffhjvbuydb78eb]

pretty sure my check valves are different. mine are "T" shaped. my truck is a 98 dodge

[@Mr.DIY69]

Where would my vaccum leaks most likely be?

[@damianvustan7583]

Will your truck idle high if these are messed up ?

[@aljuarez2909]

No, you will only be able to tell based on how your defrost position kicks in without you changing the setting

[@axelraver]

So... Where is the other video ?

[@aljuarez2909]

axelraver the other video meaning the update to whether it worked or not? I actually never ended up posting it because it did work and I would have ended up with a really short video my apologies; so if that's what you were asking yes that actually solve the issue as I had mentioned in the video Dodge uses vacuum to control the settings for the air so if you develop a vacuum leak or those one-way check valves plug up you'll experience that issue hope this video helped....

[@chucksterbright8862]

Did it fix it? Wheres the other Vid ?

[@aljuarez2909]

Chuck'ster Bright that totally work that is what the issue was as I mentioned in the video Dodge uses vacuum to control the settings of where your air comes out, so if you develop a vacuum leak or those one-way check valves plug up you'll start experiencing that problem where once you accelerate the setting will change to the defrost default mode.

[@mikeneuburger3989]

Dorman part # 47170, most part stores about $5. Ordered mine today.

[@rycher2007]

Does it matter which way they go on. ?

[@albertojuarez8741]

Jeff Henry yes it matters these are one way check valves which means they let air through one way and not the other so you need to connect them the way that the vacuum flows when your car is running disconnect one end and feel the vacuum pulling on your hose when you connect your valve you want to make sure that it's connected the way that it's going to allow air to flow going towards the vacuum. A way you can check the direction on your valves if they dont have an arrow is to try and blow air through it you should be able to blow it from one end and not the other. Hope this helps

[@mikeneuburger3989]

Gentle draw of air through it like a straw from each end will tell you which way.

[@shawnthaxton1663]

I got this same one and it allows flow either way

[@tjbohmier46]

@@shawnthaxton1663 then it is bad right out of the box, new.

[@shawnthaxton1663]

@@tjbohmier46 yes ended up getting some cheap ones off ebay that worked one from napa I got bad and one from O'Reilly's bad too out of package

[@Boblee1975]

Did it work ?

[@aljuarez2909]

Rob Wyman it totally did haven't had any issues since....

[@Samson-EC]

How did you test the check valve itself pls..thks. jc

[@aljuarez2909]

JC if you remove the check valves they are a one-way check valve if you blow through it you should be able to blow air across it and if you turn it around and try to do the same thing it should block it if air goes through it both ways that's how you know they're bad there is a little flapper inside of them that opens up when the air goes in one way and it should close off when the air tries to go back the other way.

[@Samson-EC]

@@aljuarez2909 ok, i understand. Should not be able to blow through on both ends..thks..jc

[@aljuarez2909]

@@Samson-EC make sure you test your new ones as well sometimes they come out bad out of the package

[@Samson-EC]

@@aljuarez2909 Got it. Thks for the tip..jc

[@Samson-EC]

@@aljuarez2909 Hi Al, did what you said and it checked out fine, unfortunately for me. That means I have an issue somewhere else. Thks Again..jc

[@Mr.DIY69]

Wheres part 2

[@aljuarez2909]

Actually never ended up posting part 2 I would have ended up with like a 3-second

[@aljuarez2909]

Once I actually replaced both check valves that solve my issue, hopefully this tip helps you out

[@Mr.DIY69]

How did u know they were bad? I blew into both of mine and theres only air flow one way

[@Mr.DIY69]

@aljuarez2909

[@hou.tex.]

Airflow one way = good check valve. Airflow at both ends = bad check valve. @@Mr.DIY69