Thursday, October 26, 2006 - 06:17 am, by: Rehan Bandara(Parsec)
Hi,
I have a '91 TT toyota soarer, and both the heat and air con were stuffed when i bought it.
I just forked out to have my system converted over to R134a only to find out that my compressor is leaking.
Regardless, the guy i took it to said that it was cooling down to 3 deg or so, but the compressor wouldn't click off. This guy wasn't the sharpest pencil in the box, but he claimed that this was likely due to a malfunctioning thermostat. He wanted to tear the whole assembly out from under the dash to check.. which i wasn't game for.
My knob that sets the temperature of the climate control system intermittently works, so i told him to open it up and see if any wiring behind the climate control unit is loose. I suspect this is the problem, as it only started happening after i opened the system up and toyed with it.
Does anyone know if the system goes into some sort of open loop mode if the climate control knob is malfunctioning? I have my doubts that the evaporator temperature sensor is dead, as it seems like an unlikely part to fail. Has anyone experienced a evap temp sensor failure?
I'll have to get in there with a multimeter and test it all when i have time. I hope i'll be able to fix the knob, as i got quoted $350 for a replacement from a wrecker.
The second part of my problem: My VSV is stuffed (pretty common problem, it seems). I tried doing a bypass, but i didn't have an appropriate piece of pipe to hose clamp to the rubber hose sections, so it was leaking a bit. I tried blowing directly onto the hose and found that i couldn't move any of the water through the heater core (with the heater core return hose disconnected from the block)
I was tempted to blow compressed air through the heater core to see if i could move the water, but i was afraid that i might burst the heater core and multiply my problems. So my question is; I've read that people tend to block off the heater core water circuit if the heater core is leaking. Do they do this inside the piping/core or is it just plugged out on the hoses near the VSV? Has anyone else experienced any heater core blockage before? Should i just say a prayer and blast it with 80 psi?
Thursday, October 26, 2006 - 06:24 am, by: Rehan Bandara(Parsec)
Oh, i also forgot to mention that if i pull the vsv open manually, i still don't get any hot water coming through the core, so i'm fairly sure there's some blockage in there.
I even pulled some of the ducting apart so that i could stick my arm in and feel the heater core and air dampers. (the dampers are moving, thankfully)
Thursday, October 26, 2006 - 06:58 am, by: Peter Nitschke(Pen)
To bypass the VSV, you should be able to pull the hose coming from the manifold off the VSV end at the bottom, then hook it to the top of the diaphragm dome instead of the short hose there now. VSV works on vacuum, so it only works with the engine running and blowing won't help.
Rather than blast the core with compressed air, I would be tempted to insert a garden hose into the water hose after removing it from the VSV, then slowly turn it on. Hold it in gently so it can eject if the pressure builds too much.
Thursday, October 26, 2006 - 07:23 am, by: Rehan Bandara(Parsec)
Ah yeah, you're right. Thanks for the advice.
I tried the bypass, but i still wasn't getting any water flowing. I disconnected the return hose (or at least what i think is the return hose) from the engine (It connects to a u shaped aluminum tube above the turbos. is this the one?)
I'm actually thinking the system might be vapour locked. I was thinking about it and the heater core circuit can't be in series with the main cooling circuit, so if there's an air bubble in the system, it may not develop enough head across the heater system to push the air through to the radiator. Its a bit annoying because the VSV and actuator sits slightly above the radiator, so it doesn't naturally displace any air when you fill the radiator.
I'll try the garden hose and see if i can force some water through. I seem to remember getting steam coming through the return hose once when my radiator blew.
Thursday, October 26, 2006 - 02:08 pm, by: Rehan Bandara(Parsec)
I tried sticking the garden hose in the pipe that leads off the vsv into the heater core. I couldn't get any water to move. The water just kept spraying straight back into my face.
I then tried the garden hose in the return line, only to find my cabin filling with water quite nicely!
I'm wondering whether the guy i bought the car off blocked off the heater core on the inside (past the vsv) so that he could pretend that it wasn't stuffed. How very strange. Has anyone had any experience with this? Is it common to block off the heater core past the VSV?
Looks like i'm going to pull the whole damn thing apart afterall.
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