Hi all have some questions about heater hoses and how they should be routed. First some background… I had a mechanic install an AC system from Classic Auto Air. I believe the mechanic has routed some of the hoses incorrectly and I’m looking for some clarification before I drain the coolant system and fix them up the way they should be.

For one thing the heater control valve is supposed to be placed on the return line from the heater to the engine. Says so in the manual. I believe it is currently placed on the supply line to the heater. Discovered this when I bent the heater control cable, which never functioned correctly since I got it back from the mechanic.. The temperature control **** was basically stuck on cool, which now in summer is fine but in a few months I’d have issues, so was trying to fix it when it bent. So I ordered a new cable from LMC and I’ve been researching why it bent so when i install it I can prevent it happening again. It’s the angle it was installed at by the look of it because the cable has to basically do a full 180 degree turn and I don’t think it’s made to do that.

And for another thing it looks like my hoses are routed really really wrong. I think he’s got the return line to the engine split so it’s going to the supply line from the engine, as well.

I think where the mistake happened is the supply line from the engine is actually split so that one line is supposed to go to the heater and the other goes through the spacer under the carb as a de-icer. He picked up the other side of the spacer and routed that to the heater, but I believe that’s where the split in the hose on the return line to the water pump is supposed to go.

Please tell me if I’m off on any of this. Thanks.

 

Here is how I've seen most of my trucks heater hoses routed (Sorry going off of the pictures I already have) I can take more detailed pictures tomorrow if needed.




Hope that helps

 

Your not going to get heat with a TEE installed

 

Yes it helps a lot I think - thank you. To confirm can you verify that the far side of the de-icer plate is where the heater hose on the return line T Fitting starts?

 

NoobWrench, strictly opinion but I would eliminate the carburetor spacer with the cooling ports and have direct lines going to the heater core. Install a phelonic spacer and get new coolant hoses...unless the gas freezing is a real threat where you live.

 

I am considering that, as well. I'm in SC so with the climate here the coolant running through the spacer is likely doing more harm than good - carb keeps flooding when the engine is hot. If I go that route it's easy to convert the T line on the supply line from the engine to an L line instead?

 

I'm heading this route also, never had a carb freeze up on me in Michigan. I bought some 5/8 rubber heater hose caps, will plug the fittings on the stock carb spacer and delete the excess hose/connections. I like a clean engine bay.

 

Oh just plug them and call it a day. Cool. I like that. Plus I'm worried about ordering the wrong spacer. I gave a 2bbl motorcraft and I can only find things for holley carbs... nothing for motorcraft. This is the one I was thinking about:

https://www.jegs.com/i/Trans+Dapt/96...xoCwzEQAvD_BwE

Think this or the plugs are a better route?

 

The purpose of the phelonic spacer is to isolate the heat from the heavy cast iron intake and keep the carburetor fuel bowls from boiling causing heat soak. The 2 barrel motorcraft will have the same bolt hole spacing as the Holley 2 Barrel. I've seen where a lot of guys on here go with a Holley 2 barrel as a replacement for their worn out Autolite/Motorcraft. Make sure whatever route you go, that you have a port for the PCV valve to use coming off of the passenger side valve cover. The quick and easy would be to go the local Autozone/Napa/Oreilleys and check for the spacer. They typically have them on the wall...you could always return it hassle free if it doesn't work.

 

 

I can't say on this specific spacer but I've used phenolic ones in the past on other vehicles, Eric has a valid point. Vapor lock from boiling gas can be a real pain. I used to have an old Russian army truck I restored that had a carb with a window in the float bowl. When parked after driving around you could see the gas boiling from the heat that build up under the hood. Looked just like a fish tank bubbler, typically you can't see this but the Russian had a window for my viewing pleasure, lol. I installed a 3/4 phenolic spacer on that carb and the post-park boiling stopped.

If I ran into a vapor lock issue on my truck I would not hesitate to install a phenolic spacer.

 

Awesome! Thanks so much for taking the time with that photo. That is 100% confirmation - exactly what I needed to know. Thank you.

 

no problem, glad to help ​​​​​​​

 

sorry have to ask why the heater hoses and A/C lines go through the fender instead of firewall? Assume there are another set of 4 holes into cab.
The heater valve is at an odd angle due to that.

A quad port (both hoses) heater valve works much better than a dual (one hose). If A/C performance is weak due to heat flow though heater core then suggest this upgrade.

 

I think it has something to do with the design of the Classic Auto Air system. Vintage Air routes through the firewall. Classic Auto Air routes through the fender. Maybe because they use separate heater and ac coils? And they're meant to be individually serviceable. Not sure.

But even tho they're routed through the fender tho there's no reason this mechanic should have routed the hoses this way I don't think. The return hose travels up the fender to the return on the water pump. And if he had routed the cables right then the supply cable would run up the fender but he went behind the air filter and connected it to the de icer... and then he put the valve on the wrong line... and since the line is at this odd angle my temp control cable wouldn't work right and eventually broke.

I'm sorry - if I seem bitter it's because I am. Had him install my radio too and he had it wired up so it was a parasitic drain on the battery... and the condenser set up so the belt to the steering pump was at an angle so it was squealing something awful... it's been fun.

But I've got myself a set of tools and some manuals and this forum and the rest of the internet so I'm in control now. No more mechanics if I can help it.

Thanks all!