ghettocruiser

iTrader: (4)

Whats up everyone. I decided to finally install a heater control valve in my car. Ive been suspecting that not having the valve was causing my a/c to not work efficiently.

My 87 came with a valve, but my 86 didnt. I put the HVAC controls and associated harness/hoses from my 87 into m 86, with the idea that Ide install a valve some day.

The LS1 circulates coolant through the heater core all the time. They dont have heater control valves. I never found a clear cut answer about the LS1 heater hose outputs on the water pump. Some say you can just block the flow off from them, some say the coolant has to circulate. SO I needed to find a valve that would allow that to happen. This is what I came up with.







When the temp slider is over on the hot side, the vac line going to the heater control valve is dead. No vac. The coolant flows through the valve like it wasnt there. When the slider moves over to the cold side, vacuum is applied to the line, and the valve switches so that coolant goes in and comes out on the same side. The heater core side just sort of stops. Some coolant will still squeak by, but the majority will not. I felt the hoses, and the hoses after the valve do cool down compared to before...so its working. That cools down the heater core, thus cooling down the HVAC box area, thus making the air cooler as it goes through.

It seems to work. I topped off my system with a can of 134, and now it blows very VERY cold. Just like it did in the 4th gen donor car before I took it apart. Im going to try it tomorrow on my drive home from work since it'll be hot.

Just an FYI to those of you looking for a good option. The valve is from a newer full sized chevy van...but all you need is the part numbers I gave you. It fits really good.





Thats it... not a big deal, but I dont remember seeing a heater control valve solution detailed anywhere.

Any questions?

J.

ghettocruiser

iTrader: (4)

Just for fun...

http://www.youtube.com/watch?v=yKN14bJEDmc

J.

yevgenievich

iTrader: (4)

couldn't you use the stock 3rd gen heater control valve?

ghettocruiser

iTrader: (4)

I forget why I didnt think I could use it. I think when the valve was activated, it didnt allow the coolant to re-circulate like it needed to for the LS1. Also, the hoses come off at different angles, not inline like that.

I dont have one to check to see how it operates though. I just seem to remember it not working how I needed it to.

This is cleaner since it really just splices into the hoses and keeps them inline. And its slimmer than the stock thirdgen...without the wider diaphram housing on top. I think it was $12 or something like that.

J.

Jaysz28

iTrader: (30)

looks a lot cleaner than my current setup. Might have to look into that

-jason

ghettocruiser

iTrader: (4)

I think that was the main reason...its a pretty clean valve. Tucks nicely over to the side, and is pretty slim overall. I have to get a 90* rubber elbow for the vacuum connection so I can lay the vac line down more.

This morning I had my temp set to cold for most of the ride to work. I decided I wanted some heat, so I slid it over to hot. I had been driving for like 30 minutes, so by now, the heater core would have been hot. It took about a minute to get hot air out of it. That means the valve is working...since the core was cool and took awhile to blow hot.

This also makes "vents" blow cooler if you put the temp on cold. You get more of an ambient temp air...except for the heat it picks up on the way in.

So far, so good.

J.

Jaysz28

iTrader: (30)

After looking at your pics again, I think I am going to try this.

I run that stove pipe, and I am pretty sure its letting hot coolant into the heater core.... Gotta stop that. I need all the AC I can get down here! LOL

thanks for the write up!

-jason

3.1EyeCandy

iTrader: (3)

...

Jaysz28

iTrader: (30)

Ok, can you post up a part number for the hoses, or at least a year, make, model for those of us that don't have a friendly parts place.

I'd like to get mine going next week if possible

thanks

-jason

3.1EyeCandy

iTrader: (3)

...

TPI TERR

iTrader: (9)

on your hvac controllers where does this vaccum go to or where does it come from?
i know purple is the main intake vaccum does this run into the gray one ? back to the heater control valve ?

ghettocruiser

iTrader: (4)

Its 100% how it was on the stock thirdgen control set up...assuming the car had a heater control valve. My 86 didnt have one.

So here are some pictures to maybe shed some light on things.

Here are the stock 86 controls.


Here are the 87 controls. Notice the extra piece in the upper left hand corner of the unit. This is the "switch" for the heater control valve.




The units are otherwise identical.


I THINK...not positive...that the purple hose is the vac feed for the system. In other words, you hook the hard line to the intake, and that is where the purple hose gets its vac. Then...on the heater control units, the purple hose is t'd off to go to the vac switch. On the other side of the switch, is the grey hose. That hose is dead when the temp is set to hot. When you switch to cold, vac goes from the system feed hose (purple) to the grey hose...which in turn goes out to the valve.



The other end of the purple/grey hoses coming off that vac switch.


Cont'd...

ghettocruiser

iTrader: (4)

It hooks to the hard plastic lines via a connector that can only go one way.



Finally...here is how the controls look with all the hoses and wires hooked up. I swapped the vac switch into the 86 control unit...because the 86's controls were super clean and tight and new looking. Then I used all the wiring and hoses from my 87, since I had the wiring changed for the LS1 system.



Thats the basic jist of it. Clear as mud?

J.

P.S....being able to only link 5 pictures in a post is really annoying..haha.

Jaysz28

iTrader: (30)

Thought I would add in some hose part numbers since I went out today to start this swap.

I bought two hoses at Advance Auto parts (Part #80405CS). I did have to trim 2" off the 'short' side to tuck them in where I wanted them. I will post pics once the car is more together. Right now its in 'mock up' stage.

Hope that helps others do this swap!

Jaysz28

iTrader: (30)

ok, grabbed another hose that is the correct size for the larger fitting

80416cs

pics to follow once I trim everything down to size.

Jaysz28

iTrader: (30)

Ok, got my install wrapped up and am a lot happier with it......

ghettocruiser

iTrader: (4)

Not a bad idea to have 90's coming off the valve. My 90* ends are up at the heater core, and it still seemed to flow pretty well by just putting the valve right in the middle of them.

Now that Im working at autozone again...Im going to root through the hose isle when its time to redo things, assuming Im still working there for extra cash. That is...if I dont ditch my A/C. If I do, I wont need the heater control valve anymore and will probably ditch it and run hardlines from the heater core to the pump.

Looks good Jay!

J.

scooter

iTrader: (11)

So did you use one of each of those numbers for each side of the vac control unit? or did you use 4 of the "larger", 80416cs?

1ADan

iTrader: (4)

some really good info, may add this later on once i get some of the other swap bugs worked out

Jaysz28

iTrader: (30)

I bought two of each hose.

Then trimmed them to fit the way I wanted.

I used the 90's off the heater core to get the valve on the strut tower

Then used the 90's to get down to the water pump (obviously).

I am really happy with how it turned out and it works great... got the car running today.

trans am trevor

i dont ever post but those pics of the black plug and the grey and purple were exactly what i needed! thanks

ghettocruiser

iTrader: (4)

Glad my old posts still come in handy

J.

Ikes 91Z

iTrader: (1)

I'll go ahead and unearth this post thread again...


But on the hvac vacuum line that goes to the heater control valve, what did you use to attach the line to the valve? My hvac line is much larger than the port on the valve. Wasn't sure if you knew of a good place to get the right size connector. Want to save myself multiple 30 min trips to town if I can.


Thanks for the help!

QwkTrip

iTrader: (22)

Cut off the end of the stock line and use vacuum hose to connect the two.

plum92_camaro

I had the same question when I did this. Haven't addressed it yet (plugged it, just wanted to get it running) but I am going to try using vacuum hose as to make up the difference. I don't want to cut the stock line. Call me crazy but It's just one of those things.

ghettocruiser

iTrader: (4)

Honestly Im not sure where I got the connector. I think it was in an assortment pack from Autozone. It could have just been in my pile of misc junk. Like..left over from gauge installs or what have you. But piece of vacuum line will work fine.

Justin

Ikes 91Z

iTrader: (1)

I ended up getting a small pack at o'reilly that worked perfectly for like $2. Thanks for following up.

plum92_camaro

I used a piece of vacuum hose as a spacer. Worked perfect. Didn't have to cut anything!!

Thanks for the great info ghettocruiser!

Camaro0605

iTrader: (3)

ghettocruiser, thanks for the tip. I got the valve installed and it seems to work good. I've only had the car running for about 15 minutes, but the valve worked as expected when I moved the HVAC control to Cold.

For vacuum i ran the factory hard line through the HVAC wiring harness and had it exit near the Fan Relaly. Then i ran a piece of vacuum hose from the line to the valve.

For the heater hoses I used the factory V6 hoses on the firewall. I then used a male-male adapter to connect those hoses to some standard heater hose. From the valve i used a 90 degree hose to make the bend to the water pump.

echo-delta

Hey nice install what kind of clamps are those on the heater valve they look nice?

Camaro0605

iTrader: (3)

They're Gates Power grip clamps. They work like heat shrink tubing and can only be used once since they need to be cut off to remove.

echo-delta

Thanks I didn't even know they were out there

GTA91

iTrader: (1)

I'm bringing this back from the dead.

I didn't see the part number listed anywhere in this post and most of the pictures won't show up.

I'm pretty sure the valve shown is GM 12380318 or (AC Delco 15-5533). I'm putting AC back on my LS GTA and going to try one. Very nice since its inline and I can simply splice it into my current hoses.

QwkTrip

iTrader: (22)

Parts I used are in this link,

https://www.thirdgen.org/forums/ltx-...ml#post6007199

GMan 3MT

iTrader: (4)

The one I used was 74781 from a 2000 2500 Van.

https://www.thirdgen.org/forums/memb...ml#post6143463

Aviator857

Curious how this valve has stood the test of time? The reviews online are not so great for that 4seasons part number (leaking/splitting/breaking)... I'm probably going to use the AC Delco part# 15-5533 ... I'm pretty sure that is the cross part number.

Jaysz28

iTrader: (30)

Mine is working great for being on the car for 6 yrs!

GTA91

iTrader: (1)

I ended up not even using one and my AC blows 42* out of the vent. Its all stock 3rd gen stuff except for an LS1 fbody compressor (with the 4th gen pressure sensor and PCM) and 134a Freon.

I was going to add one at one point and then didn't because honestly I wanted to keep the system clean and simple under the hood and 4 more spots for water leaks weren't too appealing... and my car sees the drag strip quite a bit.

plum92_camaro

I returned to this thread for this reason. I'm only getting 2 years from these valves. So, in the spirit of documentation here's my experience.....

I did my LS1/T56 swap in 2015, was on the road spring off 2016 and I used this valve. In 2018 it started leaking around the metal rod. When I tried to remove the old one, it literally crumbled into pieces with little effort. It scared me because I was like "what if that had let go out on the road somewhere?!". For the record I run a stock thermostat, no overheating issues.

Its now 2020 and I got the car out for the first time this morning and guess what's leaking? I came back to this thread hoping I wasn't the only one with this issue and someone had come up with a better solution. They're pretty cheap parts and replacing it bi-annually as maintenance is not off the table but I'd like a more permanent but equally as convenient solution.

GTA91

iTrader: (1)

Thanks for the update!


3yrs later and I'm still not running one due to the reasons I listed above... simplicity, cleanliness, and leaks. My car still blows low 40's out of the vent and is VERY cold. I'm not going to worry about it.

Aviator857

So far I haven't had an issue with the acdelco part, not much different in price (can find it on amazon if local parts house doesn't have it). I did have a fun thing with the heater hose I bought, it had a manufacture defect, something in the manufacturing process put pin holes evenly down the length of the hose, not all the way through but eventually they started to weep .... turned into what amounts to a soaker hose you could watch it bead up until it dripped on about 4 of the holes... at first I thought my heater core hard pipe was leaking.

Sadly it was made in USA hose.... and the replacement from advanced had the same issue, but I got that right before the world locked down and just used it for now... I bought new hose online still need to put it on though.

ILMODC

Anyone got a part number for those hoses??

Just got the deverter valve off of ebay coming.

Jaysz28

iTrader: (30)

I posted them right here in the thread

apparently my diverter valve is still working 9 yrs later......

GASPEDDLER

iTrader: (2)

I finally got around to installing my new valve last week, I purchased it off of Amazon. I installed it up high and away from my headers. I placed it next to the accumulator and away from all that heat. Ac is MUCH colder now.

rkdz28

I agree with the reasons you stated and I am at this point of my LS swap. I just installed they new heater core and was curious what type of setup you did for the hoses. I will have the all 3rd gen setup with 4th gen AC compressor as you mentioned.