Bought an LCE de-smog kit, which comes with block-off plates for the two coolant pipes that bolt to the back of the timing cover.

If those inlets to the timing housing are blocked, where would the heater hoses best be routed?

Right now, I'm thinking to run one heater hose between the intake manifold and the (ingoing?) end of the heater control valve. It's the other hose that I'm more confused about....which I guess would be the hose that exits the heater core and runs back to the engine.

Should I NOT block the coolant pipes on the timing cover? I do want heat, after all. Yet I also like that those coolant pipes going 'round back of the block have are removed, cleaning things up. Or could I just block one side (passenger side?) and run a heater hose to the (driver?) side? Or would it be okay to go ahead and block both sides, and run some sort of T-junction off the bottom radiator hose?

Not sure exactly what to do here.

 

There has to be a return from the heater core. You can't just run water in and not out. Unless your running an all our race or rock rig there is no reason the eliminate the supply and return for the heater core.

 

Did you ever figure this out? I have the exact same question. If I use those two water block plates I don't know what I'll do for heat routing.

 

Why do you want to install these "block plates"??

 

That kit specifically does state: "for those of you that are going to block off the heater core".

 

From Kawazx636 Desmog thread in the Pre84 forum " The heater hose will run from the 90* barb fitting that comes with the intake manifold plate to the heater core inlet on the firewall and then from the heater core outlet on the firewall to the factory fitting that comes off of the hard coolant pipe (mounted to the motor mount) on the driverside towards the front of the motor." Even though I haven't gotten to the point in my build, but the above is the way I have my heater hoses run. Hope this helps

 

Thanks. Yes that is exactly what I have planned to do as well. This eliminates the hose leading from the back of the timing cover on the passenger side to the underside of the intake manifold as well as the piping/hose leading from the passenger side of the head to the heater core inlet. Nice to simplify it all. I wonder if flow will be as good? And if heat will be as hot? Only one way to find out.

 

Hey Lon,
I also followed that thread from Kawazx636 along with his entire rebuild, quite amazing! What ever happened to Dave, I haven't seen him post in awhile.
Anyway, My question is does it matter which side of the heater core pipes run in and out, is the drivers side the inlet with the valve and the passenger side the outlet to the fitting near the lower radiator hose where the motor mount is. Does it matter? Does the water have a direction?

 

I ran the heater hose from the driver's side barb at the motor mount (water pump outlet), into the driver's side inlet to the heater. The passenger side outlet from heater goes through the heater selector valve to the 90 degree barb on the bottom of the intake manifold. Hope that helps. you can how they are hooked up in this pic, and it will follow the coolant flow through the heater and engine. This is not my engine bay, but you get the idea.

 

Thanks Lon, that clears everything up. My truck was so mickey moused so I wasn't able to see what it was supposed to look like.It didn't even have the valve!

 

BUT.................
I have looked at a million pics, and half show the hose coming from either the back of the timing chain cover or the lower radiator hose metal bracket that attaches to the motor mount to the passenger side (left facing the truck) heater core pipe, and then out of the heater core drivers side (right side facing the truck) into the valve and then going to the 90* fitting on the bottom of the intake manifold plate under the carburetor. The other half show just the opposite, Which is right?

 

Lon
Ok, this is what I found out. On the early trucks 1979-1983 the pic you show is correct.
On the 84-89 the coolant line from the back of the timing chain cover or the tee in the lower radiator hose by the motor mount goes to the passenger side of the heater core.Why? I have no idea, no idea why they changed it. I guess just to confuse people. Then out out the heater core on the drivers side, into the valve then goes to the barb under the carburetor.
I believe..............

 

Maybe the change had to do with the addition of the rear heater option for 4Runners?

That is my best guess.

 

Could be, and just to keep everything the same they changed the truck also.

 

Does anyone have a picture of the outlet hose where It connects? From what I understand the inlet goes to the 90⁰ barb underneath the intake manifold but any help would be greatly appreciated