[ThisGuy]

For today's edition of ThisGuy's stupid questions, we feature: "things related to heater control valves:
I've searched and searched, and I'm still searching, but I figured it would be a good idea to throw up a thread to see if someone can get me on the right path..

I see people mention 6 port heater control valves, others mention 4 ports. The one the guy at the store gave me only has two ports. It can be seen here.
Do these vans have more than one heater control valve throughout the system and he failed to give me the rest? On the website, it clearly states that it fits my 2000 Astro LS 2WD 4.3L

My next question is: where the heck is it/are they? I've seen some descriptions of where its located in other threads, I've watched a lot of videos, but I simply cannot find it. I'll attach some pictures of what I've seen versus what I have in my van. None of the examples I've seen are of heater cores with two ports.

Example 1 is what I have by the firewall, where the heater core comes out. As you can see, nothing. I saw an example of someone with a 4 port heater valve right there.

Example 2 is further down the line. Also nothing there. I saw an example of someone with a 3-port heater valve bolted onto the spot that I've circled in orange. (I guess it could've also been 4 ports, but it was a completely different configuration compared to the first example.) As you can see, someone just plugged up the lines to each other and kept it going. Do I need to add a 3-port valve right there? Can someone tell me what hose goes in which port?

Am I just tripping? Can they be anywhere else? Do I need the 2-port valve elsewhere?

 

[bryancraftyhands]

I don't know for sure, but I thought I saw some time ago that the valve is actually below those reservoirs in front of the core.
I think there is really only one valve.
As for how many ports there are, I again don't know, but it may have to do with if you have rear heat and / or AC?
In which case the pic you circled the reroute in above, is probably rerouted because they removed their rear heater, and just closed the lines off like that.

 

[ThisGuy]

Interesting. The heat never worked at all since I got the thing… front or rear
I’d like to get it all working again.

 

[Rod's Trucks]

ThisGuy,

If you follow the two black hosed shown in your first picture ( They are just to the left of your black heater box assembly), down under that box, they will hook to a black plastic valve . That is the heater control valve. Depending upon you van configuration, it will have four large ports, or six. It will also have one small vacuum hose connected to it. That small vacuum hose is the subject of most difficulties with little or no heat ( actually in those cases you only usually get defrost air) . If that little vacuum line is broken, cracked or loose, the heater control on the dashboard system gets no vacuum, and the system defaults to air blowing on the windshield in Defrost mode.
If you have rear heat/ A/C, the heater control valve will have six similar large hoses connected to it. If you only have the stock front heater and A/C, you will only find four hose connections on it.
As many have noted, those plastic valves are notorious for breaking way too easily, and most everyone suggests you have a new one in hand before attempting to replace heater hoses.
Put 'Astro van heater control valve' into an Amazon search.
It will show the 6-port as a GM #15-5551, and the 4-port as a GM #15-5557
Show that to your local parts guy.
Since you say " heat never worked at all since I got the thing… front or rear " I am interpreting that to mean you do have the rear heat unit; so you would need the six port valve.
Good luck.
Rod J
Issaquah, WA

 

[ThisGuy]

This site isn't telling me when I have replies. I'll have to check my settings. I came back to update the thread to then see someone had answered at least part of my question, merely one hour after my last reply. Meanwhile, I had been searching my butt off. Sigh. Would've saved me some time... lol
Anyway, looks like @bryancraftyhands was right about it having to do with the rear heat.
@Rod's Trucks I followed those hoses further down, but didn't see anything. I'll definitely look again. If I don't see it, I'll assume someone just bypassed it. I'll add it back in, if so. I will look at the vacuum hose, if it even has one. I will likely replace it whether I find a fault with it or not. I really don't want to do it again. I intend on replacing any and all hoses related to this system.
I do indeed have (or I'm supposed to have) rear heat/AC as I have all the switches up front. I've learned in my searches that the van has an additional heater core on the driver's side, inside the van, which I will replace (or add it in the case that I pull the plastic where its supposed to be, and find it missing). This brings me to this two-port heater valve in question. Does the LS not have two heater valves? I think the 2-port valve I was given is for the rear heater core, as pictured here (item labeled #6):

found on this site: C4E0,5E0 HOSES & PIPES/AUXILIARY HEATER; C6E0,7E0,8E0 HOSES & PIPES/AUXILIARY HEATER
The part number given is AC Delco's version of the part I linked previously in this thread. It seems like I've found the answer regarding this two-port situation. Or does the 6-port heater valve handle the rear heater core as well, negating the need for the additional 2-port valve?

So now I'll just purchase the 6 port valve, vacuum lines, and hoses, and I'll replace/add everything back in.

Hopefully after it's all replaced/added, I won't have to do any more troubleshooting and it all just works as intended.

I appreciate everyone's help.

 

[ThisGuy]

Found an answer to the 6 port/2 port situation.
Quote from another thread:

Easy enough.
1. 4 port valve for standard front heater. No rear heat. Delco 15-5557 (Should be #20)
2. 2 port valve for rear heat only. Delco 15-5586 (Vacuum operated)
3. 2 port valve for rear heat w/ AC shut off. Delco 15-5877 (Shuts off AC when rear heat is used)(Vacuum/Electric)
4. 6 port valve for front and rear heat. Delco 15-5551 (#20)

Numbers 2&4 or 3&4 are used together with supply going from engine to 6 port valve to 2 port valve the to rear heater core. Return is routed directly back to 6 port valve. This allows the rear heat to be shut off when not needed.

All 4 valves are still readily available. Shop around for the best price.

And for reference.
#12 Delco #15-30578 is the vacuum hose that controls the vent location selection (No Dash vents issue)

Seems like the 6-port and 2-port are used together

 

[MechBob]

Both valves are up front. One belongs on firewall foreward side, underneath the A/C accumulator. That is the round aluminum thing. The other is a bit further back, and up higher. Cannot get a good picture for you. I know will has a great diagram, perhaps he will check in. Also, wires go to the valve that feeds the rear. Now, as you say you have no heat, do yo mean the hoses are blocked off, or totally bypassing engine, or just the valves?? Because, I seem to remember, if both valves are bypassed, yet heater cores are still hooked up, you end up with a no heat situation. Blocking off the rear, or just pinching off one hose, gives good heat to the front. However, if heater cores are bypassed, they may have leaked.

 

[MechBob]

O.K. read this, look at pictures-

Clarifying heater valve delete/rear heater lines bypass

I've been looking around at what to do with my rear heater lines after I removed the rear heater last summer. I found some great solutions (like ChevyMaher and Lumpy's ball valves on the heater core lines) but want to clarify some information for myself and anyone else looking to do something...

www.astrosafari.com

Also, use the search box above, using heater valve, heater control vale, perhaps even with bypass added. Many threads here about such.