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heater core advice, asap (sun's going down in 2 hours)


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82 gl, pac nw

 

tubes between heat valve and core are hot, but only slight heat coming out of blower chamber. it seems hotter on driver side than passanger side. plugged up core seems logical to me. stumped on how to get the thing out. haynes manual doesn't show plethora of crap in the way or the heat valve. got a new core in the garage, but tubing doesn't look right. any additive that I can add to an isolated core to help flush out crud? Thinking of trying CLR (calcium, lime, and rust) and letting it soak.

any tips or just put on the big boy pants and start ripping stuff out?

Edited by slow be
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Try flushing it. Flush kits are cheap, and it doesn't take that long to do. All you'll need is a flush kit, something to cut your heater hose with (utility knife works), a screwdriver or bit-driver for the hose clamps (clamps are included in kit), a garden hose, and some coolant. I would recommend not getting pre-mixed, as after you flush it, the system will be full of water. So, just add about half of capacity (I think about 5-6 quarts for my EA82) worth of antifreeze, then top off with water. I think the kit has instructions, but if not, myself or someone else can walk you through.

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ran out of light yesterday and had to work today, but i had some time to think about what's going on in the dark recesses of the under-dash world, aka the heater core. methinks the little channels that run the length of the core are plugged an inch or so back and the coolant is following the path of least resistance and heading back through a clear space between the metal tubing that goes into, and out of, the core, rather than circulating throughout the core and dispersing heat. that's why there's a little heat on the driver's side, where the exchange tubes attach to the core, and almost none on the passanger side (the deepest part of the core). it's a theory...

 

i75eya, the heater hoses go from the engine toward the firewall, and then connect to metal exchange tubing that goes through the firewall, under the dash, and to the heat valve and core. it looks like the valve controls how much flow of heated coolant can get to the core, just like a valve on a garden hose. when i turn the hot/cold dial on the consol, the valve opens and closes. in my case, both tubes were hot on the core side, so i think the valve's flowing well.

 

since the core that i'd ordered is a bad fit, i have some time to fiddle with the old one that's still holding tight in a jungle of wires, brackets, and a million more little screws.

 

the new plan is to use a little submersible garden pump in a tub of radiator flush solution and continually flush the core for a couple of hours. im hoping the continual exchange of solution directly through the core will help aggitate and dissolve the gunk causing the blockage. i can set up the system, head to work for a couple of hours, and come home to see what happened. if that doesn't work, i'm going to borrow an air compressor from a friend and turn it up to 11.

 

dj, i forgot to mention i'd already flushed the cooling system this fall in an attempt to get heat in the cab and as general maintainence. the kit was really easy to use, but didn't do much for the heat.

 

oh yeah, i looked on the back of the CLR bottle and it mentions not to use on brass or copper.

 

subaru's are a learning process...

Edited by slow be
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A lot of times the gunk clogging the core is gooey rather than solid deposits like calcium. In that case the best way to clean the core is to disconnect both heater lines, hook one up to a garden hose, and turn the hose on slightly. The higher volume and pressure from the hose will clean out the gunk deposited by the low volume, low pressure flow from the engine.

 

You don't want to go full blast on the hose if the core is badly clogged because it may burst (they're designed for 13-15 psi operating pressure, your hose is about 40 psi). I would start with the hose at a low flow rate, then turn it up incrementally as the heater core gets flushed out and starts flowing better. At the auto shop I used to work for we'd do this and leave it flushing for 30 minutes to an hour depending on how quickly the flow improves.

 

If it is hard mineral deposits like calcium then the core probably isn't salvageable.

 

Good luck, I need to do this to my new Brat as well...

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i75eya, the heater hoses go from the engine toward the firewall, and then connect to metal exchange tubing that goes through the firewall, under the dash, and to the heat valve and core. it looks like the valve controls how much flow of heated coolant can get to the core, just like a valve on a garden hose. when i turn the hot/cold dial on the consol, the valve opens and closes. in my case, both tubes were hot on the core side, so i think the valve's flowing well.

 

Thanks for clearing that up. I'm going to do that same check on mine to see if it's the valve or the heater core itself. Where exactly under the dash is the heater core located, I'm going to assume it's passenger side footwell. I've ripped out the glovebox in the loyale once before (I forget why actually lol) and remember seeing that that is where the blower fan is located if I'm not mistaken.

 

Is it a real P.I.T.A to get to it? I'd like to flush out the core...

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don't turn the air compressor up to 11.

use a small cheap one without out a whole lot of force, I believe a large compressor might damge the core.

I have founf the air to be much more effective quickly then other methods.

this spring I intend to get filters for the cooling system for both my cars.

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Thanks for clearing that up. I'm going to do that same check on mine to see if it's the valve or the heater core itself. Where exactly under the dash is the heater core located, I'm going to assume it's passenger side footwell. I've ripped out the glovebox in the loyale once before (I forget why actually lol) and remember seeing that that is where the blower fan is located if I'm not mistaken.

 

Is it a real P.I.T.A to get to it? I'd like to flush out the core...

 

On an EA81 it's right in the middle next to the accelerator pedal. It might be in a slightly different spot on your EA82, but I doubt it. To flush the core you don't do anything inside the car. If you remove your spare tire under the hood you can see two black heater hoses going to the firewall. These connect to the heater core and you just disconnect them to flush it. Make sure the car is cold so you don't get burned by hot coolant, and have a drain pan underneath to catch the coolant. I usually flush a gallon or so of water through the core into the drain pan to get the last of the coolant out of it, then let it flush out onto the ground after that since it's just water with some chunkies.

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post-37387-136027652616_thumb.jpg

 

post-37387-136027652621_thumb.jpg

 

I think the slow core flush worked!:Flame:

 

Well, i won't be cooking gas station burritos, but it's waaaay better. Hot air blowing out driver side and passenger side on the floor. I set up the system and let it run for about 4 hours today while I was making money for the cause. Tomorrow's a short day at the coal mine, so I'll probably mix up some fresh solution and let it flow while i'm putting everything back together in the cab, maybe squeeze out a few more degrees. The water in the catch basin started as clear water and finished as whitish-green murk. I could barely see the pump in the bottom of the basin when I opened the hood (maybe 4-5" under the surface).

 

i hear snow's on the way, so it's going up to the local ski hill for the first time next week!

 

4wd and heat---plush! :D

Edited by slow be
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