Heater problem NOT vsv issue.

[nitroneon85]

Hi there. I have an 88 N/A that has cold heat. I've searched all the NO HEAT posts and all say the vsv is bad and don't go into much more. My b;ower blows fine in all positions, not circuit. My vsv has vacuum an dmoves up and down freely and when supposed to. My passenger heater hoses are hot to the touch, my driver hose is cool, that is my main concern. Is water not flowing through? I dontknow if that would be a clogged heater core, or if the blend door actuator would control that? When I lower and raise the heat to hot and cold I dont hear any movement of doors behind the glove box or anything. Ive tried two heater units from an 87 and 88, and one from an 89. No change. Any help would be appreciated. Thanks

 

[clutch]

Loosen up the line on your vsv and pull hose back and have somebody start the car. If no coolant starts to come out push or pull on the lever and wait for coolant to start to circulate then push hos back on and tighten clamp. Sounds to me like you have a air bubble that is trapped and that will also stop you from getting heat inside the car. Had it happen to me a couple of times.

 

[nitroneon85]

If both hoses relating to the vsv are hot, into vsv and out of, wouldn't that mean coolant is flowing? The problem seems like its not getting fluid through the core. Should the driver side hose coming out of the firewall be hot from fluid exiting? Could I disconnect the hoses and blow through them or compressed air?

 

[MightyAl]

Your heater core could be clogged. If it is they are a treat to change out.

 

[nitroneon85]

Is the dash coming out the hardest part of the job? If so it doesn't sound that hard. I just replaced the dash when I changed the color of my interior and it was a breeze.

 

[GrimJack]

It's not *hard*, it's just a long job. Popular opinion states that the assembly line for the Mk3 starts with a heater core, and everything else was built around it. You have to pull the dash, the crash bar, and a significant portion of the HVAC system under that to get at the heater core. Plus you'll need some special o-rings and clamps from Toyota. It's such a nasty job, Toyota didn't even include it in the TSRM.

Sounds like you're going to be doing it, though.

There are no other valves in the system, so coolant in the passenger side should be coming out the driver side.

Might be worthwhile to disconnect both lines to the heater core and try to flush it with something pushing more pressure than the stock system.

 

[nitroneon85]

Yeah. If it gets above 20 degrees out soon I want to tear into it. I was thinking hooking a garden hose to it and blasting it backwards and see what happens.

Even if the hot cold actuator under the dash wasn't working, the driver side heater hose would still be hot correct? Thanks for the replies


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[GrimJack]

The actuator under the dash only affects the air path for the cabin, it has zero effect on the coolant path through the heater core. So yes, the heater hoses should both still be hot.

 

[nitroneon85]

Ok thanks everyone. When it warms up a little I'm gonna blast the hose in it and troubleshoot it. I'll let you know what happens. Thanks again


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