Cooling troubles............still

Ok since I overheated....I have

Replaced radiator $200 (had no choice in the middle of the night...AutoZone it was)
Replaced thermostat $$?? (forgot the price but not overly costly...also AutoZone)
Replaced upper and lower radiator hoses $$?? (again not costly but it counts in my book as money put in)
5 gallons of coolant @ $11.72 a pop (11.72x5=$58.60)
Replaced plugs with NGK V2's @ $2.79 apiece (2.79x4=$11.16)
Replaced cap (again forgot the cost)
Replaced rotor (forgot again)
Replaced plug wires (cost more than I wanted to spend but oh well)
And today I was having MASSIVE heating issues...so I checked my heater core and its so damn plugged hardly ANY coolant/water was getting anywhere...so it got bypassed

1 4' section of heater hose (given to me from the Home Depot guy cuz he put away some other parts I had out)
4 new screw hose clamps @ 1.05 apiece (1.05x4=$4.20)
1 3' section of copper tubing $2.79

and while I made it home without overheating...the temp did climb....stayed in the normal area but not in the middle...more in the middle upper area....and when I shut the truck off you could hear the boiling into the overflow (which still had fluid in it..so assuming thats a good sign...since it wasnt pouring back in)...and for the first time I got the damn truck...my radiator cap was HOT....like normal feeling hot after running...normally its been cool to the touch...so again a good sign as I know the engine is heating up the oil and not just making it sludge....and I ran the whole way home with my electric fans on...never shut em off at all.....

so my question then is this....

WHAT THE HELL IS GOING ON WITH THIS DAMN TRUCK????

I am not finding coolant in any cylinders (will be checking after it cools down some tonight), its not in my radiator (as far as I know...again will be looking tonight) and not in the oil that I have seen as my dipstick is showing golden oil color........I just dont get it....I will be pulling the head, getting it surfaced, and replacing the headgasket regardless if it needs it or not and also might do the water pump whil I am in there...figure its just good measure although today I saw it pumping coolant quite well.

Just frustrating.......thanks for letting me rant and vent

What i think that might help you better is to know what temp the coolant and motor are actually getting to. Maybe the stock mazda sensor in the coolant neck has gone bad over the last 20 years... and is not to accurate. But from what you have done it sounds like you have done everything right. Next sounds like you need a heater core.

other factors , outside temp, is your electric fan wired properly, such as is it a push or pull fan?

But i would check to see that the coolant is being opened at 180 or what your thermostat is...

Its been a while since i have played with the mazda motor but from what i remember there are coolant passages in the intake mani, and there are rubber hoses that come out of there, make sure those and the mani aren

Thanks bro....actually gonna get all the hoses replaced...and I am not sure about the sensor really.....I know when I first got the truck it NEVER hardly moved...always REALLY REALLY low....well today is the first time I have seen it move up and stay anywhere normal whatsoever....it was kinda cool actually...lol...know that sounds weird but after weeks of it hovering near cold and then the one time it went up it overheated.......such a strange lil truck I have

i'm having the same exact problem. i put a new t-stat in and still. a bad water pump could also cause that problem. i've seen w/p's have their prop. section erode and cause it not to flow enough. so for my truck i'm either going to go with a new w/p or sensor. i might just change the w/p anyway and see what happens.

Not experience from a Maz, but if the heater is plugged you might try back flushing the cooling system,its likly all plugged up if the heater core is plugged(these circulate coolant thru the heater all the time wether you have the heat on or not) Just a thought.
Gimpy

Your timing could be off(lean).Are there bubbles in the coolant? Compression gases could heat it up. I would check the temp with a temp gun or temp probe from a voltmeter. Hate to ask but it is 50/50 mix coolant? You could remove the t stat and the upper radiator hose and check the water pump output.

could be the water pump. if its the original one the fins on the pump could be worn off over the 20 years of use.

When installing a new thermostat make sure the jiggle pin is at the top. I usually leave my rad cap open untill the tstat opens to make sure the coolant is flowing. If it starts to overflow, your thermostat could be stuck or you may have air in the system.

rememer just because the tstat is new doesnt mean its any good i have had a few bad brand new...take it out and drop it in boiling water to see if it opens
if it does your fan clutch may be bad...does your fan spin free it should have some resitance