heater question 70 c10

[theredmeadow]

I have a 1970 C10 5.7L and it's supposed to have AC but the compressor was removed when I got it. All the heater hoses that go to the radiator and compressor are gone. Is it possible to still hook up the heater without the AC compressor? I've seen a diagram that shows one line from the firewall go to the compressor and the other to the radiator. Without the compressor where would I hook up the line?

[Andy4639]

I've never seen a heater hooked up to the ac compressor.

[GuyO]

To my knowledge, yes. First, move the radiator connection and then route the hoses as normal. One to the left of the thermostat housing and the other hose to water pump. These are big block pictures but I don't think it matters. I have used a brass plug for the radiator connection.

[Andy4639]

Here is the factory hookup of AC/ Heater hoses. Heater and AC are sperate systems they don't connect to each other.

[theredmeadow]

Originally Posted by Andy4639

Here is the factory hookup of AC/ Heater hoses. Heater and AC are sperate systems they don't connect to each other.

out of these images am I going to need the water valve? also it cuts off the image of the other hose? where does it connect? I have NONE of these hoses and I've never had to connect up a heater from scratch. More images with a clear idea of where they go from point A to B would be very helpful.

[theredmeadow]

Originally Posted by GuyO

To my knowledge, yes. First, move the radiator connection and then route the hoses as normal. One to the left of the thermostat housing and the other hose to water pump. These are big block pictures but I don't think it matters. I have used a brass plug for the radiator connection.

I have no idea which hose is which. I have no hoses connected anywhere when it comes to this heater. The little hose connectors that stick through the firewall is all I see coming from the heater. the radiator has 1" plugged hoses connected.

[GuyO]

The images above do show they are separate systems so you shouldn't need the AC compressor to get heat. Some confuse the Evaporator Core Assembly with the heater. The heater hoses originate like you say from between the fan motor and the Evaporator Core Assembly. Run new hoses (5/8" and 3/4") from there to the water pump and intake manifold and you should be OK. Plug all other holes in the compressor and radiator. G.

[FirstOwner69]

Here is a picture of how my 69 has always been with a 350, short water pump and original radiator. If any of your A/C brackets are present they may be different, but that is not relevant. I think on some later model trucks (71s and 72s?), one of the hoses went to the radiator. I believe the 70s used the same routing as my 69. The 3/8" hose attaches to a nipple on the top front of the intake on the passenger side (note the clamp near the center of the picture). The 3/4" hose attaches to a nipple on the passenger side of the water pump (clamp at lower edge of picture left of center). These hoses then run to the nipples on the heater core. Normally the top heater core nipple is the 3/4" and the bottom is the 5/8". The A/C trucks also had a clip to secure the hoses to the inner fender. I'm not sure if the A/C trucks used the same clip.

It's very possible the heater was disconnected because the heater core leaks. Be ready to deal with that.

[FirstOwner69]

Originally Posted by theredmeadow

out of these images am I going to need the water valve? also it cuts off the image of the other hose? where does it connect? I have NONE of these hoses and I've never had to connect up a heater from scratch. More images with a clear idea of where they go from point A to B would be very helpful.

You don't need the water valve if you aren't running the A/C. Also, the manual pages posted above show the installation on a 6 cylinder.

[Andy4639]

The hoses can be hooked up in several differant ways depending on how the person wants them done. Some use the radiator for the return some use the intake.
Water pump hose is supply to lower heater core hose. return is upper heater core hose to whereevre u want it to be.
This is my setup on the 71.
I have a later model 305 TPI motor though so it's not going to look like a 307, 350 truck motor hook up but it does the same thing.



I typed where the hoses go in red.

[theredmeadow]

I think I found what they've done. They just looped a hose to both ends. I've drawn lines to the hookups, tell me which picture is correct please. Also, I've include a picture of what my interior heater vent situation is, can I still run the heater without everything else just to get some heat inside?

[FirstOwner69]

That'll do it! As I said above, don't be surprised if the heater core leaks. Don't know any other reason it'd be hooked up as it is.

EDIT: You must have still been posting pics. You'll find that pic 2 is what you'll have to do since the 5/8" core nipple is the bottom one and 3/4" is top. Everything under the dash appears to be disconnected, too. Obviously, the core needs to be enclosed and controls hooked up. It also appears the existing hose loop connects the 5/8" intake nipple to the 3/4" pump nipple. Surprised it doesn't leak.

[theredmeadow]

Originally Posted by FirstOwner69

That'll do it! As I said above, don't be surprised if the heater core leaks. Don't know any other reason it'd be hooked up as it is.

EDIT: You must have still been posting pics. You'll find that pic 2 is what you'll have to do since the 5/8" core nipple is the bottom one and 3/4" is top. Everything under the dash appears to be disconnected, too. Obviously, the core needs to be enclosed and controls hooked up.

Yeah I just got this truck and started the restoration. LOL Part of start up is I gotta get all the little loose ends buttoned up. They said that the engine was rebuilt. A lot things were disconnected. I'm not sure if the heater core leaks but Can I hook up the hoses and test?

[FirstOwner69]

Originally Posted by theredmeadow

Yeah I just got this truck and started the restoration. LOL Part of start up is I gotta get all the little loose ends buttoned up. They said that the engine was rebuilt. A lot things were disconnected. I'm not sure if the heater core leaks but Can I hook up the hoses and test?

Sure, just be ready if it leaks.

[Andy4639]

The factory drawings work for either motor doesn't matter. Water pump is for pumping the hot water to the heater core. Outlet goes to wherever you want it to to return to the system. The motor has nothing to do with the way they hook up.
U may get some heat out of it after running the hoses, but without the rest of the cab vent stuff it want be much and no defrost.
U can hook your water hose to the heater core and see if it leaks.
Sometimes when the truck is being used in the hot summer months people un hook the heater so the AC will run coolier if the water valve is leaking by. I always run a manual shut off also to make sure it doesn't heat up the core when using the AC.

[theredmeadow]

Hey guys!! SUCCESS! No leaks and the heater blows hot air! Thank you!

The heater doesn't blow on high though. Why?

[FirstOwner69]

I Googled the forum for "high fan speed" and got a bunch of returns. I read the 2nd and 3rd. Below is a link to the results of the search. Happy reading... Incidently, my blower has never run on high, even when new, unless the ignition key is in the on position. At least, I think that's where the key has to be, but I can't double check since the truck is 150 miles away. That's not relevant though if you are saying yours isn't working on high with the engine running.

http://www.google.com/custom?domains...D%3A1%3B&hl=en