Coolant System Bleeding w/Rear Heat
 

https://cimg9.ibsrv.net/gimg/www.maz...9f9184b7c7.jpg
What is this valve for? 2006 MVP w/rear heat
Also, I think I have air in coolant system, Just changed thermostat becaue of intermitent heat and now heat temp is low. I have been doing the 4000 rpm for 1 min/idle for 1 min procedure and it seams like the air is getting warmer. But still not hot. What are your thoughts?

Welcome to the forum

.Anybody know?

I don't guess (unless I have a reasonable thought and then state it is a guess on my part) sorry and I looked at what remains of OEM parts illustrations and couldn't find the part. I can only state that it is a vacuum controlled valve.

You need to be patient, with the holidays a few of our regular members that have these models and work on them regularly I am sure will respond.

.There is nothing attached to the valve. It is manual.

The arrow indicates a specific flow direction. There does not appear to have a "manual" cable but it looks like in the picture that a vacuum size hose may at some point be attached to it????? But without better and more pictures it only GUESSING!!

Most all HVAC system for the heater core coolant flow control are not uncommon using cable, electrical and vacuum controlled vales and or solenoid.

If there is nothing at all connected to it remove it and see what happens?

Here is the picture of the valve from a Mazda dealer. The part no. is LD4961170A.

Ok yes that is possibly the part, is there a question?? The parts guide is not showing the information you should have entered to make sure it is specifically for your Mazda. VIN and possibly manufactured date by month and year
The problem with your find is it still does not state manual cable or vacuum operated?
Your picture as I stated is not clear enough either?

No one can help if you don't provide answers to the questions to help you!

There is nothing attached to valve. No cable, no hose. You manually operate with hand.
I have a 2006 Mazda MPV ES VIN JM3LW28J960556957.
My main question is how to purge air out of coolant system. I didn’t know if this valve to heater core had something to do with that.
Thank you for taking time to help me.

The cooling system bleeding all coolant delivery hoses must be active. it helps if the front of the vehcle is slightly raised if only a few inches.
There were never and head casting never had issues with your model Mazda so bleeding should not be difficult to do. Your thermostat also should have a "jiggle" valve, so bleeding is somewhat done just by driving.