I have a 91 runner with the 3L cooling/heating system. I poked a hole in one of the rubber lines feeding the rear heating core just under the body.
I have two questions. Do I need to drain the radiator, or is my system independent? (From what I can gather it is joined on the 22re but not on the 3L? About 3 quarts have drained out so far and it seems to have stopped). Also, can I use regular radiator hose, or are those hoses something special that I need to order from the dealer?

 

Should be similar to the 22RE setup, coolant from the engine flows through the rear heater core just like the front heater. It will essentially drain all the coolant out as it is one of the lowest points in the system.

Typically regular heater hose works fine, I used some heater hose (1/2" or maybe 5/8") as I recall.

 

hey there 4crawler, if you have a spare few minutes, mine explaining (or giving me a link to an FSM that has the info..mine doesn't) the Rear Heater in my '92 4runner.....it blows ice cold air sooooo i kinda wanna fix it lol

 

Highly complex device there. Two hoses, one for hot coolant from the engine, one to return coolant to the engine. Inside a valve that is operated by the little temperature lever and a fan, operated by the switch.

So make sure the two hoses are indeed hooked up, common for them to leak and a quick fix is to just take one hose (the one not leaking) and loop it back to where the other hose used to connect on the engine. If hot water getting to the heater, then back flush it with water to see if it is plugged up inside. Backflush? I.e. run water (like from a garden hose) into the outlet of the core and let it flow out the inlet and force out any blockage. Which is the inlet? The one with the valve usually. Or flush one way then the other, repeating until the water runs clear.

 

Wow, i can honestly say i REALLY did think it was more complicated than that...thanks for replying to my Noobie dumb question lol

 

Is there some trick to getting the hoses off the core lines? I moved the clips off, but the hoses are stuck like glue, which is how there came to be a hole in the first place.

 

Usually if you can grab the hose below the connection and twist it back and forth, that can help to break it loose. Otherwise, use a sharp knife and cut the hose off close to the end and then slit the remaining hose on the fitting and peel it off. I find that applying some dielectric or silicone grease to the hose fitting before slipping the new hose on makes future removal a lot easier.

 

^^ works great .. also try some pliers and turn the hose at the connecter back and forth .. be careful the heater tubing is very thin , you can bend it out of shape real easy .

also a pick with a curved end .. try to slip it between the hose and tubing to break it loose .

 

Ok, I just took the whole thing out since those hoses were looking rotten anyway. The final question is, Can I just use some regular old hose clamps instead of the funky cotter pins that join the hard lines under the body? I understand why springs are used on the heater coil itself to keep from bending the copper, but those lines under the body look more substantial and those cotter pin clamps are just weird and a major pain.

 

I used regular band clamps on mine. I also soldered a threaded end and put a 90 degree elbow on each line to make it easier to access from below:

 

You also dropped the driveshaft, which makes things a whole hell of a lot easier. For such a minor thing, the rear heater is a major pain to get to and work on. Thanks for the help!

 

Just had the shaft out when that picture was taken. I recall doing the work on the rear heater lines (1st gen) when the shaft was installed.

 

Dual cases don't help. Luckily, all I had to remove was the heat shield and I was able to get at it the hoses without slicing my hand. Still a very tight squeeze.