1987 toyota supra heater problems
 

i just replaced my heater control valve and my heat is still not working. i have fan motor bypassed with a switched 12v so i can turn it on cuz my factory control box would not turn it on but everything else on control box worked now with heat on full blast i get no heat only cold air. i would love to get my hands on a wireing diagram for he heat and air system for my 1987 toyota supra if anyone has one.

Dont know if this will help you, but when my heater was blowing cold air I by-passed my heater control valve, straight from back of head to firewall and worked great after that.

Rob, does the valve open when the engine is running and the heat is on? The VSV is trouble-prone at this age. Run a vacuum line to by-pass the VSV straight to the valve. I did that, and now the valve opens. The VSV will open the valve anytime the temp setting is above 65 deg. Here's a site with pics:http://www.ddmcse.com/turbo/heatervs.htm

If the valve opens, then the problem is most likely with the blend doors under the dash that control the temperature. For directions to inspect and repair, check the TSRM:http://www.turboninjas.com/mk3supra/

My heater core is clogged up from the previous owner pouring in radiator stop leak for now I use a harbor freight 12V heater. You should check it out they are only $9.

By Pass
 

I would like to try this bypass but my car is an NA, I have no heat in my car. I looked at the link and then looked at my car. Here are a couple of pics, is the line in the second pic the one you connect to the top of the VSV and if so what do you do about the hole left where it was connected or do you T it off?

Please explain exactly what is done better than the person that made that post. Thanks, Scott

They appear to be using different lines in these two pics from two different posts to make the bypass.

I fixed mine. it turned out to be a problem with the heater control valve. i did the same thing they did on the picture with the blue vaccum lines. i used a T connector on a vacumm line on the driver side of the engine bay( cant remember exactly which one i sold the car) and used the extra port opened up by the T connector to run a vacumm line across the fire wall to the heater control valve. any vacumm line anywhere on the motor will work as long as its a constant vacumm. this will keep the valve open so there is always coolent running into the heater core therefore the heat is always ready for you when you hit the heat switch to open the door on the heater box.

Success
 

SUCCESS
I just drove my car for about an hour and a half with no over heat, car ran at half way or below at all times on highway and in town. I didn't want to stop driving. It had been a long time since I had driven a Supra.

The FIX
I physically opened and closed my heater valve till it loosened up and burped the system with my heater on heater valve (VSV VALVE open) then I pulled the thermostat and tested it in heated water till it fully opened up. I also broke off the dangle and drilled the hole that the dangle left to a 4mm size.

I reinstalled the stat, refilled the system and burped it again.

This morning I drove it into town and had a Blown Head Gasket Test done on it and the motor passed.

I hadn't overheated or lost fluid on my way to the garage so I decided to run it till it overheated to see if I still had a problem.

Drove it for a long time about an hour and a half in city and highway and it appears to be fixed. Evidently I don't need my electric fan on to cool the motor it is 86 and sunny today.

Special thanks to
mrnickleye for his suggestion of drilling the thermostat, That made the difference! Either the new thrmostat had been stuck or I had air pockets in the heater core still.

What it took!

Used Starter
New Air filter
New Spark Plugs and Wires
Helicoil Spark Plug hole repair Kit
Dome light repair with small screw
Fog Lights installed
Swapped Passenger seat
Running light Bulbs
New Valve Cover Gaskets
New Timing Belt
New Coolant
Fresh Gas
New front crank seal
Plenum gasket
2 new front Venturas HR II tires
2 used Eagle GT rear tires
New Horn
New Castrol GTX Oil and Bosch oil filter
New Cannon Exhaust, adapter pipe, clamps, and sealant
New Rear Pioneer Speakers
2 Keys made from code on passenger side door lock
New Battery
New Thermostat
New Radiator Cap
New Water pump belt

It's the little things to fix now as time goes by, like rear power antenna, AC, electric fan, yada yada yada.


Thanks so much to the members of this board with your help my car went from sitting 7 years to a functional good running daily driver. I have to admit that the sense of accomplishment is tremendous.

than the vsv was the problem.. good, hope it dosnt get all sticky on you again.

Vsv
 

Yeah I hear ya, the heater valve is open for now, long as the air is out I should be OK. It seems to be on open for now, I have some little bit of heat coming into the cab even when I turn the heat off, but I have heat! I can drive it now and not eagle eye the temp or have to stop and refill it.
"Oh WHAT A Feeling! TOYOTA!"

the og batmoble was at a wallgreens in my town today..