kevino

Is there a way to do this? I would like to unclogg it without running something through my coolant system. Is there a good way to flush just the heater core?

NZConvertible

How do you know it's clogged? Is the valve opening when you set the temp to hot?

kevino

Well it only sometimes put out heat. I've tried hooking up a hose to it and it doesn't come out the other end.

NZConvertible

Hooking a hose up where? In the engine bay? If the valve isn't opening, either because it's stuck shut or because the Logicon isn't telling it to open, no water will flow.

You need to visually check the valve's operation. That fact that this problem is intermittant points to the Logicon.

kevino

sorry I didn't specify, when I said I connected a hose I meant I connected a garden hose to the input end of the heater core (through the fire wall) and no water came out the output end. So there is a valve that stops coolant flow through the heater core? That doesn't really make sense to me that flow through the core needs to be stopped, I thought coolant constantly flowed through it and shutters controlled whether you wanted heat or not. Could you please explain this setup to me more. For more insight, the heater would only put out heat every now and then. For the most part, there is no heat coming out of it (while the heat is turned on) and then all of the sudden heat will come out. Then it will stop again.

NZConvertible

There is an in-line valve the controls coolant flow through the heater core. The valve can be adjusted from closed to fully open or anywhere in between by the Logicon. When the temp slider is fully to the left (cold) the valve is closed and no coolant flows through the core. When the temp slider is fully to the right (hot) the valve is fully open and coolant flows unrestricted through the core. When the temp slider is part way across the valve is partially open and coolant flows at a restricted rate. This is how all nearly car heaters work.

kevino

when you say "temp slider" I assume you mean the temperature adjustment on the dash board controls right? So the temp slider is linked with the logicon,and the logicon then tells the valve what to do? Is this correct? So how can this malfuction be remedied? Or am I all backwards about this?

NZConvertible

The Logicon is the HVAC control panel (which has the temp slider on it) and yes, it controls the opening of the heater valve.

A very common cause of HVAC problems in FC's is a faulty Logicon. Poor quality soldering eventually fails and causes erractic behaviour of the various parts of the system. Search for "Logicon" and you'll find info on fixing it.

You should also read the Body Electrical chapter of the FSM for more info on the heater valve. It might pay to see if it's jammed.

RXSevenSymphonies

iTrader: (2)

You should be able to hear the valve being actuated very faintly when you move the temp slider.