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Hello everyone, so I've been fiddling around with my 84' trying to square away all the problems I inherited when I bought it a few years ago. This episode surrounds the interior heating problems I've been having. Blower works, position, speed, recurring and fresh work, and the air direction work. The problem is that no heat from the coolant is being blown through (only heat I get is during the summer months) I've gone through a few possible culprits in attempt to fix the problem, I used a garden hose to force water through the coolant hoses to check if the heater core is clogged, I lubed the heater valve because it felt stiff when moving it and I manually open the valve using a hand vacuum pump, to which I do feel hot coolant flow through so I know its moving somewhere (I also think the vacuum valve things next to the washer fluid tank are a possible culprit). All have yet to provide hot air, so I took the dash out because the only other thing that my mind thinks can be the problem, is the heater core, or the climate control unit, my pops suggests its the unit, but before I spend more money on parts that may not fix my problem, I figured asking the sages of the Celica Supra forums before I do anything else. Help?
 

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Refer to the TSRM. There are multiple sensors that control heat/COOL.
The black cigar-looking thing by the condenser MUST be connected. There is also a sensor inside the center console.
Heater core is a 2 day job! You will hate yourself!
Some one put in a MANUAL heater control valve from a......TRUCK?
Full vacuum should open the heater control valve, if it is functional.. :unsure:
 

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I have a fully manual system, (no A/C) but my first check would be to check the hoses going into the firewall, they should both be fairly hot when the heat is on. Also try to manually open the valve with a vacuum pump, a large syringe would actually do if you don't have a hand operated one.
As the core most probably is of the crossflow type, I don't suspect a bad divider, like in many european cars. Those are frustrating.. :p
Remember, this is not rocket science, logic works! :D
 

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I have a fully manual system, (no A/C) but my first check would be to check the hoses going into the firewall, they should both be fairly hot when the heat is on. Also try to manually open the valve with a vacuum pump, a large syringe would actually do if you don't have a hand operated one.
As the core most probably is of the crossflow type, I don't suspect a bad divider, like in many european cars. Those are frustrating..
Remember, this is not rocket science, logic works! :D
@Beernuts hey man I'm converting from the automatic HVAC to a full manual heater system. I got rid of all the ac components and crazy vacuum lines and valves. I bought all the hvac ducts from a RA64 celica with no a/c. I got the heater valve too. I was curious where you have your heater valve mounted in the engine room? On a LHD car seems like it should go on the driver side next to the brake booster. There's a blue cable that goes from the controls inside the cabin to the valve and it pops out in that spot. Do you have any pics? Any other tips on the manual set up?

Sorry don't mean to hijack the thread. I can great a new one if this gets too long

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Dave is right in that there are many sensors in the system, and the FSRM has a trouble shooting section to follow to nail down this issue, but in my experience this problem is usually caused by one of 2 things. For one, if the AC has been removed, there is a little temp sensor up there that people often remove when they toss out the condensor too. You have to un screw it from the condensor and leave it mounted up front or you get the exact problem you are having right now.

And if thats not it, the most likely reason is one or both of the VSVs under the windshield washer bottle have stopped working. This is getting very common on these cars as they get older, and why peeps like the above like to switch to the simpler system in the Celica. I havn't looked for new replacements yet, there may be some. I've had enough used spares so far, but I should look into that soon. They are easy to bench test. Add 12v, and they should open and you should be able to blow thru them. Remove power, they should close.
 

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The VSV needs vacuum AND voltage ON/OFF ?
I have the opposite problem. I get heat ALL of the time, so I just pull the vacuum hose off and plug it or just pinch the vacuum hose. ;)
 

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There's 2 VSVs there, each causes a different problem if it doesn't work anymore. A VSV is just an electronic valve, open or closed. If vacuum is hooked up to it, it will allow vacume past it when it opens. If it has positive pressure plumbed to it, it will allow air to pass thru it when it opens.

One of these VSVs is what feeds vacume to the heater core valve to open it when the climate system sends a signal..
 

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@Beernuts hey man I'm converting from the automatic HVAC to a full manual heater system. I got rid of all the ac components and crazy vacuum lines and valves. I bought all the hvac ducts from a RA64 celica with no a/c. I got the heater valve too. I was curious where you have your heater valve mounted in the engine room? On a LHD car seems like it should go on the driver side next to the brake booster. There's a blue cable that goes from the controls inside the cabin to the valve and it pops out in that spot. Do you have any pics? Any other tips on the manual set up?
Not trying to hijack this thread either, but here's a pic from a washing event.. :p
14735

A bit unsure where the cable comes out, but it's not far from the valve.
Note that this model do not have any of the emission control systems either.
As I have never seen an A/C setup, I have no clue about the difference! :p
 

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14738


Surprisingly inexpensive from the dealership, like under $30 inexpensive...
 
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I saw prices down around $20 at some online Toy Dealers!!
 

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Does anyone know if a manual heater valve is still available? I looked up the part number for a celica st. It's 87240-14120. Everyone says discontinued. So wondering if a manual valve from another toyota vehicle would work? I have one that came from a celica that sat in a junk yard for like 20 years so honestly I don't know if it even works.



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I'm sure you could adapt just about any manual heater core valve from any car.
I think that one from the euro car posted above is the celica valve adapted to fit there. Note the blue cable, I think the owner made that cable.

But parts availability is still good on our valves, and heater cores too so that's a plus to keeping the stock system. The VSVs that fail are common too, every Toyota has them, just different arrangements of brackets and clips, they pretty much all work the same. I've seen aftermarket replacements for them on newer cars too.
 
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