[DML] Re: Cleaning off heater core to improve airflow

["Dave Swingle" <swingle_dmc@xxxxxxxxxxx>]

Is the air flow bad all the time or only on heat? If bad all the time 
the evaporator screen is plugged, if only on heat it's the heater 
core or some flaps that are not moving correctly. I've never seen a 
dirty heater core, but then again I haven't seen many cars with 190K 
miles on them either. 

If you are lucky you can take the blower motor out and reach your 
hand in there and clean much of the screen that goes over the 
evaporator. Be sure to vacuum everything out or you'll trade lack of 
air flow for lack of drain water flow. Unfortunately you can't reach 
the water drain since it's on the other side of the evaporator. 

You can't easily reach the heater core at all without taking the 
whole case out of the car. It may be possible to disassemble the 
whole dash and remove the heater core box leaving the evaporator case 
in place, but I've never tried that. (You'd still have to disconnect 
the water lines.) There are a couple of screws that hold it in place 
that are close-to-impossible to reach, and if you do get them out you 
won't get them back in again. 

Make sure all your flap acuators are working too.  

While you're in there, make sure that the blower motor is working 
properly and that the resistor pack has not become corroded. 

Also - you didn't happen to recently replace the blower motor, did 
you? There is a very common cross reference motor that turns 
backwards. Interestingly enough a cage blower turning backwards still 
moves air in the right direction, just not very much of it. 

Also part 2 - make sure that the sponge that seals up the heater 
tubes is still in place. When it falls off a lot of air will leak out 
the back of the housing. You reach it from the driver side and have 
to feel your way behind the heater box to where the heater lines exit 
the box and go out thru the body. 

Dave S

--- In dmcnews@xxxxxxxxxxxxxxx, "ksgrimsr" <knut.s.grimsrud@...> 
wrote:
>
> Hi guys,
> 
> I'm getting pretty low airflow through my heater/AC system and 
suspect 
> that I have an accumulation of lint on the heater core restricting 
> airflow (which would be reasonable for my 190K mile car).
> 



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