New 87 mk3 owner with some questions.

[twixmix]

Hi new to the forums and my 87 with 111k on the clock. i have a few problems with my car. First off my heater doesn't work but it does blow cold air and my passenger side carpet is wet(I've read around and I'm guessing its coolant). So now I'm thinking its a bad heater core. Also my coolant level light is coming on even though i just filled up the radiator and over flow tank but when i checked the over flow tank today it was empty. Are these problems related and if so would replacing the heater core fix it? I tried zip tying the vsv and still no hot air. Also when I took out the glove box I noticed duct tape covering two holes
that I don't think should be there. And what is the sensor circled in blue? And where should that be? Any help is much appreciated

 

[tsparks01]

I have an 88. This behind the glovebox picture looks familiar. I have this part exposed for an ECU swap right now. I will look today after work and get back to you.
The sensor does not look familiar, and I just replaced every wire from the engine to the ECU plugs. I will look again.

i have one of those for sale, ill take a look at it and get back to u, but i thik there is a port on the right where that goes in to, right where the hole is

 

[SURUKO]

that is the solar sensor for the a/c amplifier...

 

[jetjock]

^ Correct.

OP: Fwiw that's the evaporator enclosure. Heater core lives elsewhere...

 

[toy fanatic78]

Correct,that sensor should be in the top of the dash in the far right of the defroster vent,supposed to have a plastic piece and cover that clips into.And yes,the heater core leaking will cause your radiator to empty itself,wouldn't drive 'til you get that fixed.

 

[twixmix]

thanks for the help. so the heater core leaking is what will cause the passenger side carpet to get wet?

 

[jetjock]

Well, is the wetness coolant? A leaky core can cause it. So can a plugged AC drain hose but in that case it'll be just water. Based on your loss of coolant it's likely the core though. Much fun fixing it.

As for the holes these days it's common for HVAC techs to inspect an evap for leaks using a flexible borescope. The latest ones even have IR leds on the end to illuminate AC dye. They could have been drilled for that purpose although most techs will usually go in elsewhere. Maybe the guy was just a butcher. Anyway, seal 'em back up...

 

[twixmix]

Well, is the wetness coolant? A leaky core can cause it. So can a plugged AC drain hose but in that case it'll be just water. Based on your loss of coolant it's likely the core though. Much fun fixing it.

As for the holes these days it's common for HVAC techs to inspect an evap for leaks using a flexible borescope. The latest ones even have IR leds on the end to illuminate AC dye. They could have been drilled for that purpose although most techs will usually go in elsewhere. Maybe the guy was just a butcher. Anyway, seal 'em back up...

well my interior doesnt smell like coolant but yeah my coolant is going out pretty quick and its not leaking outside of the car. i ordered a new heater core so ill get that put in and see if it fixes the problem...and yeah that should be pretty fun hahaha :1zhelp: and any suggestions on what to seal the holes up with? id rather not use duct tape again

 

[jetjock]

You could always get some coolant dye in order to verify the core is leaking. For the holes buy some plastic snap in plugs at the local hardware store. RTV them in if you have too. Put the solar sensor back where it belongs. You can do that when you pull the dash out to replace the core. Also be sure to replace the seals on the piping connections and you should pressure test the cooling system before putting the dash back in. You don't want to do this job twice...

 

[twixmix]

You could always get some coolant dye in order to verify the core is leaking. For the holes buy some plastic snap in plugs at the local hardware store. RTV them in if you have too. Put the solar sensor back where it belongs. You can do that when you pull the dash out to replace the core. Also be sure to replace the seals on the piping connections and you should pressure test the cooling system before putting the dash back in. You don't want to do this job twice...

alright thanks for the tips. i ran the car a little today after filling it up with coolant and this time i did notice the smell inside the car and also a hissing noise coming from the vents every so often so i went ahead and ordered the heater core. hopefully after i get this done i wont have any more problems for a while

 

[johnny]

Here is a picture of my 88. I don't know why the holes are in yours.

 

[iwannadie]

alright thanks for the tips. i ran the car a little today after filling it up with coolant and this time i did notice the smell inside the car and also a hissing noise coming from the vents every so often so i went ahead and ordered the heater core. hopefully after i get this done i wont have any more problems for a while

Well you need to find out what caused the heater core to leak in the first place other wise your new will suffer the same fate.

FWIW I had a blown head gasket, it was letting exhaust into my cooling system and blew the heater core.

 

[ForcedTorque]

Is there a tech write up on heater core replacement? I will look, but it's gonna be a little while before I do. If anyone has it easily accessible I think it would be a good add to this thread.

 

[cuel]

Most of the time, heater cores leak due to deterioration over the years. Could be electrolysis, or simply rusted and corrosion due to too much water, not enough coolant. A lot of vehicles have a ground strap on the heater core(not sure about the Supra), so if there is one there, be sure to put it back on. It would be a good idea to flush out the rest of the cooling system while you have it apart, and use the correct coolant mix. I usually use 50/50 coolant and water, as it's easy to get the mix correct.

After you get the heater core in, and the hoses on, fill it with straight water, and pump the pressure tester(you can usually borrow one from Auto Zone, Pep Boys, etc.) to 15 lbs., and let it sit for 5 to 10 minutes. If it moves, you have a leak somewhere, and need to find it. If it doesn't move, you're good to go. Remove the pressure tester, drain the radiator and block(the drain is under the exhaust on the side of the block, back by the trans. iirc), seal it up, and fill with your coolant mix. Pressure test it again to make sure neither of the drains are leaking, and you're good to go. Easy, right?