Mazda MPV Climate Control
Hi all...
I have a 97 mpv that up til now has ran flawlessly aside from maint. items form time to time. :sick: Recently, i noticed a marked drop in temp from my heater....and it's getting COLD in Ohio. My temp gage reads in the normal range so i decided it may be time for a flush. Flushed the system , refilled and flushed a second time with straight water as instructed in my shop manual. Now I have NO heat. I have airflow, so I figure that the ducts aren't clogged. Removed the trim and checked that the air mode and temp blend controls are working. I noticed something in the manual that said there is always circulation to the heater (even if the termostat is closed) unless the a/c is set to max or the system is switched to off. Is there a coolant valve that is operated electrically that I'm not aware of? If so, does anyone know where it is? Any help would be greatly appreciated.
I have a 97 mpv that up til now has ran flawlessly aside from maint. items form time to time. :sick: Recently, i noticed a marked drop in temp from my heater....and it's getting COLD in Ohio. My temp gage reads in the normal range so i decided it may be time for a flush. Flushed the system , refilled and flushed a second time with straight water as instructed in my shop manual. Now I have NO heat. I have airflow, so I figure that the ducts aren't clogged. Removed the trim and checked that the air mode and temp blend controls are working. I noticed something in the manual that said there is always circulation to the heater (even if the termostat is closed) unless the a/c is set to max or the system is switched to off. Is there a coolant valve that is operated electrically that I'm not aware of? If so, does anyone know where it is? Any help would be greatly appreciated.

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Comments
I would bet on the clogged heater core
-Brian
Mazda was very helpful and I hope that they will pressure Denso to keep parts on hand for vehicles that are at least under 10 years of age, or force them to release product design data and part numbers, so that another company can make up for Denso’s incompetence.
Mazda referred me to Mazda Mart 800-221-5156 who was able to determine the correct ac compressor for my van at a reasonable price of $250. I would still like to only change the ac clutch which promotes a greener environment because even when you do it correctly a little always leaks...
Hope this is some help and relief for the summer heat...
Thank you very much.
What was the solution? I have a 1998 MPV with the same problem. The rear heater unit works and the temperature of the water going in and out of the core is approximately the same. Plenty of airflow. I am suspecting a broken damper inside the duct. Hope to hear from you.
Thanks
Thank you
I noticed you had a similar problem to mine with your MPV heater. Did you find out what was wrong?
Thanks
Choquer
You can check underneath the van on the passenger (right) side below the sliding rear door. You'll see aluminum tubing for A/C going to the rear wheel well and if you have rear heat you'll have black steel tubing. They may be wrapped in foam along the way and will have 2 tubes each.
-Brian
Ok , I will check for the tubing. There is an overhead selector for fan speeds 0 thru 3 (I think) same as on the control at the front operators panel. So I presume the heater feature is there.
What kind of problems can there be with the rear compartment heat?
There is a Special Service Bulletin for that leak, that extended coverage to 7 years. Replacement tubing and removal of the plastic guard in the wheel well is the fix.
Another possibility is that the flow switch up front behind the engine has the rear heat tubes getting no coolant. Possibly for the reason above, or perhaps because of previous work. Yet another possibility is that air is in the lines and needs to be "burped" out.
-Brian
Foxmike
http://www.mpvclub.com/tsb.php?id=152
For whatever reason, the tech always like to fool with this valve...
-Brian
-Brian
-Brian
I'm currently having what sounds like the exact same problem with my 2000 MPV. Were you able to figure out more information on this?
Thanks in advance,
Darryl