mazdahacker

Interior Heating Not Warm Enough

14 posts in this topic

Hello, motor warms up really nice and fast, like 5 mins of driving and its around 85 C but the interior heater blows not so hot air. Where should i start looking for problem. Ive topped coolant 3 times now and it seems it cant take more. How to check for trapped air? I guess a car like that could deal with traped air itself but you never know right? What to check?

Thanks

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Check the fresh air mode blend door (requires partial dash disassemble).   Warm air is being lost through the fresh air vent because the flap isn't sealing all the way.  That's a good place as any to start really.  Have you thought about or tried flushing the heater core to ensure it's not clogged?

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I think my heater radiator is clogged with leaves and seeds, coz i read somewhere that theres no filter on the car with no AC. I got leaves and debris coming out of the air vents. Id really like to check the heater radiator...do you happen to have video or diagrams how to reach it?

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Heater core has nothing to do with leave and debris getting in.  They are getting in through the fresh air vent that feeds the blower motor.  The fresh air vent is directly in front of the windshield on the grated cowling piece.  The vent is only ever found on the passenger side of the 626.  When leaves and debris fall into the grate they get sucked down into the hamster wheel then shot out through the air vents.  That's the path of air from outside to inside.  Keep your grate clean.  You can access the blower motor wheel by removing the glove box.  You'll have to disconnect the resistor plug and unscrew the motor.  Then you'll see it.  It looks like a hamster wheel. Clean out the area and reinstall.

 

Turn on your air and set it to full blast.  Set it to fresh air mode.  Then go outside and feel the grate in front of the windshield on the passenger side of the vehicle.  Then you'll see where air is getting sucked down and you'll know the area to keep free of debris. Try not to park under trees if you can help it. :)

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Oh I see what you mean.  Good question. I'm not going to speculate.  I don't know the answer to that one.

 

If you really want to get at the heater core you have to disassemble most of the dash to get at it.  It sits directly in the middle of the dash basically behind the two front center vents. :(

 

Read up on the procedure in the 1996 Body Electrical Troubleshooting Manual.  Currently it's the only BETM for any year 626 available online.  The general procedure for dismantling the dash in that manual applies to all 1993-1997 models.  Read the HVAC section.  There are going to be differences between years but that's the only manual currently online that covers it.

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No, it's buried back behind the HVAC control module (heater controls) then behind that is some vent ducts and behind that is the heater core.  It's really hard to access.  I've never had to remove it yet so I can't offer any advice.  Ask RacerX.  I know he's removed his heater core... because I have it sitting in a box in my garage. :P

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I think my problem is trapped air in coolant system. I had the funnel in place and pressed coolant hoses.. I managed to get some air bubbles out but it feels like theres still air inside and i cant get it out. I'll try raise the front up and try again. Any suggestions?

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If you have air in the cooling system it's getting in somewhere.  That means a leak.  Unless you've recently performing a coolant change there shouldn't be any reason for air getting into the system. You can add fluorescent dye into the coolant and any leaks can be detected with U.V. light.

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I know how i got the air in, i accidentally unbolted the little block that attached to engine block while i was changing clutch. That shouldnt have been removed actually.

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Does your car have aircon as well? Here is a very basic block diagram showing you how everything is assembled behind the dash.

 

post-30971-0-58505800-1409469617.jpg

 

So let's break it down:

 

1. Fresh air in from outside with recirc flap open or from inside car if recirc flap is closed and fan on.

2. Air travels either through a duct between the fan and heater(non air con) or through the air con evaporator, to the heater.

3. Heater core gets hot if the heater tap is opened.  The air then passes over the heater core on its way through to the vents.

    Based on where you have the temperature control sitting, the heater tap may be wide open or only partially opened, and the

    heated air can be being mixed with outside air or the air con to regulate the temperature.

 

Questions:

1. Have you checked your heater tap is functioning correctly?

    Unfortunately, this will probably be inside, in a really crap spot near the firewall, to check if working correctly.  Just check where

    the heater pipes enter the vehicle and somewhere near them, will be the heater tap.

 

2. Are your heater controls vacuum or electronically operated?

    If your controls are vacuum operated, I would be checking for perished vacuum hosesWhat could be happening is that

    some flaps that should be closing, may not be because of a loss of vacuum.

 

3. Does your cooling system have a thermostat? 

    If you are not running a thermostat, the water could be circulating through the block too quickly not allowing it to get hot

    Worse if the car is moving because the air flow across the radiator keeps the coolant cooler than normal.

 

Leaves in the ducting will only restrict air flow, not alter temperature.

 

Hope this helps a little.

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OK, next..........

With your heater on, check if the heater hoses in the engine bay, are hot.

If they are not hot, once the car is up to operating temperature, check hoses are not blocked and check heater tap operation.

If water in the supply hose to heater is hot, and return hose is cold, then blockage or non functioning heater tap.

If yes, then follow them through to the cabin area and see if they have a similar hot temperature feel - they should.

If no, then you have a blockage or your heater tap is not functioning.

 

I was thinking that if you had AC, then one of the air mixing flaps was not operating correctly in the heater box, allowing cold air to mix with

the hot air.

 

It might also be worth your while buying a thermometer and putting it in the centre dash vents to see what temperature the air is exiting at. Then check

the outer vents as well.

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