How to fix No Air from Vent / Vacuum / Intermittent AC Issue

Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby 81SAFARIMATT » April 4th 2020, 6:52pm

so amazon sent me 2 of the tube that goes from intake to check valve.... anyone wants one and near fort collins co I will have on on the shelf in the shop....Matt

edit ...a valve just arrived also and i have extra vacuum tube ...guess i have a kit now ...
98 safari...3 seats...4.3 v6....RWD...130,000 miles new .... LOVIN LIFE IN THE COLORADO MOUNTAINS

No good story ever started with a salad
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby gman » April 6th 2020, 9:09pm

I just did this without removing the air cleaner. I had my doghouse off anyways as I wanted to get a look in there and I'm going to do a tuneup.
The end behind the doghouse is connected by some sort of t-tap on the same line that goes into the PCV valve. Pretty easy to find. In my case it was a broken elbow which made it extremely obvious.
Once I found that, I just kinda folded it and pushed as much as I could of it over the top of the air cleaner duct that goes into the throttle body.
I came around the other side and it pulled right out and connected to it's place on the front of the van.
I prefer this routing because it protects the hose, and I just have to remember it's there whenever I remove my air cleaner for whatever reason (Will do it soon to clean throttle body and possibly do an MPFI upgrade with a $100 spider that I found).

I turned on my blowers and woo! I got air. All of the modes seem to be working properly, (you can hear the system get closed once you put it on max AC), so pretty soon I'll see if I can do some kind of pressure test on the HVAC system, and if there are no leaks, or if the leakdown is extremely minimal, i'll recharge it.

2 minute job if you do it like that.
Just thought I'd throw that in there in case anyone removes their air cleaner as a first step.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby AstroWill » April 6th 2020, 11:28pm

gman wrote:I turned on my blowers and woo! I got air. All of the modes seem to be working properly, (you can hear the system get closed once you put it on max AC), so pretty soon I'll see if I can do some kind of pressure test on the HVAC system, and if there are no leaks, or if the leakdown is extremely minimal, i'll recharge it.

If there is any leak you should fix it properly before you charge it.

Trolls take away from productive work, best to starve the troll of attention by ignoring it and going about your business.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby gman » April 7th 2020, 6:19am

AstroWill wrote:
gman wrote:I turned on my blowers and woo! I got air. All of the modes seem to be working properly, (you can hear the system get closed once you put it on max AC), so pretty soon I'll see if I can do some kind of pressure test on the HVAC system, and if there are no leaks, or if the leakdown is extremely minimal, i'll recharge it.

If there is any leak you should fix it properly before you charge it.


How do you fix leaks without ripping the entire system apart? Replace the lines or use a pipe clamp?
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby AstroWill » April 7th 2020, 7:15am

Most of the leaks occur at the compressor belly seal, the compressor to pipe seals or the o-rings in the system.

If it's a line there are various ways, but usually the best is to simply replace the line.

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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby gman » April 10th 2020, 5:47am

AstroWill wrote:Most of the leaks occur at the compressor belly seal, the compressor to pipe seals or the o-rings in the system.

If it's a line there are various ways, but usually the best is to simply replace the line.


Thanks. The air actually gets pretty cold fairly quick, but it just seems "weakly cold" rather than just a blowing of air, which is what an A/C'less car feels like.
But, ultimately the pressure test will show. I'll check those areas if it shows any leakdown.
If not, i'll recharge and have cold air (though it's a pretty low priority honestly).
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 22nd 2020, 2:37pm

So I’m seeing the same issue on my 2002 Astro. Rear AC is blowing ice cold but there’s no air coming from the front vents. There is air coming out of the front floor vent, the windshield defroster, and the mirror defrosters but it’s not cold. What percentage of the time is the vacuum line noted in this thread the cause of this problem?

I didn’t pull the air cleaner off yet but when inspecting the line it appears to be attached and I can’t see any visible cracks. If it’s not this line, what else could be causing this?
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Leeann_93 » June 22nd 2020, 10:07pm

Check the line from end to end. The elbow could be split or loose, the line anywhere along the length can be cracked.

If it's intact, time to check all the other vacuum lines and check valve that the suspect line attaches to on the passenger side of the engine bay.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 23rd 2020, 12:25am

Leeann_93 wrote:Check the line from end to end. The elbow could be split or loose, the line anywhere along the length can be cracked.

If it's intact, time to check all the other vacuum lines and check valve that the suspect line attaches to on the passenger side of the engine bay.


So I did a more thorough inspection of the line, and still didn't see any visible cracks and it appears to be attached on both ends because I can pull on it and it doesn't move. Should I just buy the part and replace it anyway? How small of a crack or hole can cause the issue?

Is there a diagram/video/post that details how to check everything else you mentioned that may be causing the issue?
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Leeann_93 » June 23rd 2020, 12:35am

Look back a page.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 23rd 2020, 12:48am

Leeann_93 wrote:Look back a page.


Okay thanks, I hadn't quite finished looking through the whole post yet. So I should check vacuum lines first, then the check valve?

Going back to my last question, how small of a hole can cause issues? Should I just replace the line noted in this post anyway if it's the most common cause of this issue?
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Leeann_93 » June 23rd 2020, 1:04am

Any hole is a leak.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 23rd 2020, 2:17am

So would my best course of action be to just replace the vacuum line noted in this post and see if that fixes my issue?
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby sixsix » June 23rd 2020, 2:04pm

Gu3nth wrote:So would my best course of action be to just replace the vacuum line noted in this post and see if that fixes my issue?

:banghead:
Well, after all... what would Banacek say ?... “AOC - her astonishing matryoshka-like ignorance, like the rest of The Squad is surpassed only by the relentless idiocy of the democrats, antifa & it’s attendant mass media, mayors & governors.”


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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 23rd 2020, 7:44pm

I looked through this post but no one really seemed to address my question. If the line shown in the original post doesn’t appear to be cracked after a visual inspection, should it still be replaced since it appears to be one of the most common causes of no AC out of the front vents? What’s the order I should follow when trying to diagnose what’s causing my problem?

-where are the other lines located and can they be changed following the same procedure?
-do the other lines have specific GM part numbers or can I just use vacuum tubing from the auto store? It seems like some people have done it this way.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby sixsix » June 23rd 2020, 7:57pm

Gu3nth wrote:I looked through this post but no one really seemed to address my question. If the line shown in the original post doesn’t appear to be cracked after a visual inspection, should it still be replaced since it appears to be one of the most common causes of no AC out of the front vents? What’s the order I should follow when trying to diagnose what’s causing my problem?

-where are the other lines located and can they be changed following the same procedure?
-do the other lines have specific GM part numbers or can I just use vacuum tubing from the auto store? It seems like some people have done it this way.

:banghead:
Well, after all... what would Banacek say ?... “AOC - her astonishing matryoshka-like ignorance, like the rest of The Squad is surpassed only by the relentless idiocy of the democrats, antifa & it’s attendant mass media, mayors & governors.”


.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby Gu3nth » June 25th 2020, 2:59am

I fixed it! My issue wasn’t the line noted in this post but was actually a couple of the other vacuum lines. They were rotted and split. Now I have air out my front vents, but it doesn’t blow cold. Off to figure that out!
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby GuyS » July 31st 2020, 11:12pm

I used the first posters method to try and fix my blower motor issue. I found the line the OP described and it was broken. So I replaced it with GM part 15967970. Still no blower motor. I ended up replacing 3 rubber vacuum lines from the vacuum reservoir and to the valve and T. They’re really easy to replace. I just bought rubber vacuum hose from a local auto parts store and cut to fit. All of the original rubber lines (GM 5/32 6148) were rotten. You don’ need GM hoses. I replaced 3 lines and used 2ft of hose to replace the original 3 lines. Blower motor works now.
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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby sixsix » August 1st 2020, 4:02pm

GuyS wrote:I used the first posters method to try and fix my blower motor issue. I found the line the OP described and it was broken. So I replaced it with GM part 15967970. Still no blower motor. I ended up replacing 3 rubber vacuum lines from the vacuum reservoir and to the valve and T. They’re really easy to replace. I just bought rubber vacuum hose from a local auto parts store and cut to fit. All of the original rubber lines (GM 5/32 6148) were rotten. You don’ need GM hoses. I replaced 3 lines and used 2ft of hose to replace the original 3 lines. Blower motor works now.


Could you explain how the "Blower Motor Issue" was solved by replacing Vacuum Lines ?
There are quite a few here that would appreciate your easy remedy info as they all had to change a Fan Speed Resistor Unit within the Blower Hsg. itself.

While on the other hand... Air ( hot or cold ) not coming from certain vents, defrost or floor generally points to Vacuum Lines or actuators.

Glad you and the previous poster got your Air Moving Properly !!
Well, after all... what would Banacek say ?... “AOC - her astonishing matryoshka-like ignorance, like the rest of The Squad is surpassed only by the relentless idiocy of the democrats, antifa & it’s attendant mass media, mayors & governors.”


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Re: How to fix No Air from Vent / Vacuum / Intermittent AC I

Postby GuyS » August 1st 2020, 4:54pm

Oh. My fan was not pumping air out the vents. The fan would come on and change speeds but would not direct air out of the vents in the dash and on the floor. I may have mislead by saying “blower motor issue”. Fixing the vacuum lines enabled something to work so the air was redirected. I am guessing the flapper valve is controlled by some kind of vacuum controlled valve (but could be wrong there too!).
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