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Discussion Starter · #1 ·
Hello! My GF and I both have astrovans. Hers is a 2003 4.3l and Mine a 97 4.3l. My research has landed me here and what a great community it is! This site has already saved me a lot of headaches. Both of our vans have the problem where the heater controls don't direct the air anywhere it is just stuck on defrost. I found that both of the main vacuum feeds were completely rotted and broken off. Through the sticky I found that part#15967970 is the feed from the engine block to the connector on the top passenger side of the engine bay. Is this OEM part the best solution?

I really don't like the thin plastic lines I would rather use rubber vacuum hose. I can't see or reach where I think the line comes out of the engine block. In the sticky it said removing the dog house wouldn't help but I don't see any other way. My arms aren't huge but they can't fit in where I think the connector is.

The rest of the vac hoses are also so brittle they turn to dust if looked at the wrong way. I want to replace everything while I'm in there. is 5/16 vac line the correct size for the whole system? some of the parts are a little tricky to reach with a hose clamp just curious if it can be done without hose clamps?

Also she only gets cold air (no heat) while my van I can control either cold or hot. I am wondering if her heater bypass control valve is stuck shut or if hers should be getting heat regardless of the vacuum problem. When I first found out about the issue I was thinking heater core but need to fix this vac issue and see which way it goes. I really appreciate any insight into this issue and happy to have found such a plethora of knowledge about these awesome vans!!
 

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Common Sense + Critical Thinking
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Very common issue and yes you can replace them with rubber hose, or you can buy the tubing at your online or at your LAPS(usually in the HELP section). Either way you go, they will eventually need to be replaced again as they get old. Replace 1 section as a time so you don't mix them up.

To get at all of the lines, removing the engine cover will make everything that much easier. While you are in there, check your coil/distributor/wires etc.
 

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If you try and name the size (5/16, 3/32 etc) you'll go nuts. Some places call it TUBING (which should be measured by OD), some call it HOSE (which should be measured by ID), and some call it one and measure the other.

Simpler - Snip off an inch, take it to LAPS, ask for ten feet of that. About ten bucks. Replace everything.

Do that every couple years. Never have vacuum problems again.

Lump
 

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Discussion Starter · #4 ·
Thank you for the insight. I will take a piece of the line down and see what they can give me. If I do 2 vans should I get a little less than 20 like 15 feet or is that cutting it too close? :D Also do I need to get hose clamps or will I be able to connect the engine block main feed without it? Some of the connections like to the heater bypass controller are a little tricky to get to so not sure if you guys are using hose clamps on everything? Really appreciate the info! Thank you!
 

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Just make sure to shop around, the prices can vary widely across the street. You can get 20 and save the leftover for some other time, it doesn't deteriorate quickly if it's not under the hood so the extra will last in your toolbox/glovebox/jack storage compartment.

No clamps. I usually slit the hose/connector before trying to remove it from some of the more sensitive components like the heater bypass, they tend to be fragile.
 

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Discussion Starter · #8 ·
Awesome Thank you!! I will look into the silicone for next time. I think I will just get the regular stuff this time so I can verify that it is indeed my issue and I want to get it done today if I can. Much appreciate all your help!
 

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Discussion Starter · #9 ·
Also one more question how hard is it to get to the vacuum line that goes to the dash controls? It's not broken but if I don't have to do much additional work to swap that I would like to change it as well. Anyone have any pics or just some tips on how to get the controller and fish a new line out?
 

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Now that gets a bit more complicated.
It generally ( always ? ) is a different type of Tubing / Hose.
Much smaller in diam , totally a different material - harder and more prone to Kink when brand new.
It might be as small as 1/8" / .125" OD with an ID of 1/16" / .0625". Totally apprx. dims.
From past history it is not the stuff that generally goes bad.

Be aware there are many different Vacuum systems/styles used on the Astro / Safari line.
And as many variations as there are GENS, models, years, engine & intake types.
The Emissions Evap systems adds even more vacuum lines - 2 or 3.

Research your 2 Van's Vacuum systems before digging in too deep - they might not be the same.

Mike
 

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Discussion Starter · #11 ·
Really appreciate all the input. I finished running new vac lines on both vans today. I just went for the line they had at the auto parts store and now that I'm familiar with the job the next time I have to do it I will get silicone lines like suggested. I didn't do the line to the control as I figured I wouldn't have to pull the doghouse again to do that part, I will most likely also replace the T's in the system as they are old too. The hardest part of the whole thing was getting that damn doghouse cover out of the front without screwing up a hose on the engine. The vacuum ball was also a little tricky to get a line on but not terrible. Really can't thank everyone enough for giving me the confidence and info to get it done.

I don't know if I should start another topic but when I got done on the 2003 astro which has rear heat/ac. The heat does work but it seems like it doesn't blow really hot unless I rev the engine a little bit. Before I changed the lines I had absolutely no heat at all. I do have control over where the heat comes out via the dial but it seems like it doesn't blow really hot unless I have my foot on the gas. The rear heat blows hot all the time now. Is it possible that I still have a vacuum leak or should I flush the heater core? I originally had suspected the heater core before I found these vac lines looking like swiss cheese. Thanks again for the help everyone! :D
 

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Willy Loman, Tom Joad, Vladamire and Estragon, Kerouac, Ghengis Kahn, and I think Justin Bieber, many famous personalities started out by tackling their vacuum lines. Once armed with that kind of confidence, nothing is impossible.

Lump
 

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wjustadv said:
Hey! Astronot have you figured out your issue??? You seem to be having the same issues as me. My vacuum lines look like chop suey and i have only a slight warmth to my heat.
Welcome to the Forum - Having Heat / Vacuum / Water Valve Problems ??
Maybe we can help...

:rockon:

Mike
 
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