ok so a coworker has a an 84 gs that she hasnt had too long. anyway, its has 12x,xxx miles on it and its having an overheating issue. she said that it just started a few months ago. it gets hotter alot faster in stop go traffic, but on the highway it takes alot longer.

she said her brother replaced the thermostat already, it was an oreilly one, not the mazda OEM one, which i think may be some of the problem. anyway, i looked at it today and the clutch fan just spins, it has no tension on it, so i think that may be some of the problem. also the upper rad hose wasnt getting full of pressure, so maybe water pump too?

any suggestions would be helpful. i didnt smell any coolant in the exhaust and it looked normal, so i dont think its a coolant seal.

 

You need to replace the fan clutch. More than likely your problems will go away after that. Also have the cap pressure tested or if it is the original just get a new one.
Make sure that there is at least a 50/50 mix of coolant/water.

And also check the tension of the belt.

 

Always use an OEM Tstat, never an aftermarket. they are different.

Go to your local Pick 'n Pull and get a new fan. Too bad you missed half price days last weekend.

Flush out your cooling system. it's easy.

 

the oem T stat has a bleeder hole to allow air to excape while refilling coolant after a flush. It is important to have this so you dont have to mess with the cooling system for a long while to get all the air out. ALSO DID THIS PERSON PUT THE tSTAT IN THE CORRECT WAY????? OR IS IT BACKWADS. ( sorry I left my caps lock on from below )

it sounds from your desciption that the car still gets too hot at highway speeds just that it takes longer.

a couple of things: if the fan blows a lot of air at idle or at least at low speed your fan is doing its job well enough and its best to first look elsewhere for your problem. at highway speed the fan is NOT needed at all.

That being said, as the upper hose felt soft at temperature your system is not presurizing either becauce there is too much air in the system unlikely with this car. OR the dreaded coolant leak... So I second the motion to do a cap pressure test. BUT IF THE COOLING SYSTEM IS VERY OLD AND DETERIORATING
ONLY PRESURE UP TO ABOUT 7 LBS. AND SEE IF IT HOLDS THAT, YOU COULD CRACK OPEN SOMETHING GOING UP TO 15 LBS IF THE COOLING SYSTEM IS WEAK.
You still need to be able to drive around to get parts!!!

And lastly did someone use a bunch of stop leak, I believe it plumets heat transfer.

TRY THIS.

Drain the system

Save the coolant- check color of coolant

Find out about the Tstat install and if need be buy a new tstat gasket and sealer and have a proper tstat ready if needed and check behind.

Do you see a bunch of stop leak in the cooling system

Refill the system with the correct quantity of coolant. if you cant get all the coolant in there, air is trapped in the system - again unusual for this car.

Pressure test the system. and check if the big hoses are firm

If all is good to go here check behind your work at intervals to see if coolant is still completely topped off - if not an engine O ring ect could have a leak giving exhaust gas into coolant and coolant into engine at too slow a rate to notice anything while driving. Is there a hint of coolant smell in the exhaust?

otherwise was there a leak, then determine if it is internal or external?
is the radiator brittle and disintegrating?
stop leak gunking up the system?
a hole somewhere?
smell coolant in exhaust? smell coolant in the interior?
Does the water pump pulley wobble and are you loosing coolant from its seal.
How much coolant is missing after how many miles of driving and what kind of driving?


Use a 7 lb cap instead of higher and drive gently ( granny style - car is on probation ) until you correct the problem.
But you must correct the problem soon or you will hurt your engine

Basically how is the radiator, the hoses, the heater core inside the car,
the water pump pully wobbles? or again its in the engine?

thats a good place to start?

this is how youl find your answer........ let us know what you find.

 

btw ther is a fan shrowd there ( soory for sp its too late)

 

removing duplicate

 

If you have an after market T-stat drill a tiny hole, maybe 1/16 or 1/8 in diameter in the t-stat. This will have the same effect of the OEM t-stat with the hole in it.

I just bought one from RockAuto
I plan on drilling a small hole in mine to allow the air to escape. Some may recommend against this. I have had mechs tell me it works fine though. I wouldn't go any bigger than 1/8 though, you do not want water passing though the hole easily, as it really defeats the reason for a t-stat.

I also have a bad clutch fan. I idle raises the heat in the car fast. Turn the heater on and it will cool down the car as well. running the heat in the summer time sucks... but it will save your car.

 

solutions from cheapest to not-so-cheapest

1. New Rad Cap
2. T-stat, mazda OEM
3. Water temp sensor (if it goes bad, you might not be running as hot as you think)
4. Flush and fill coolant (use Prestone "Super Flush" and water, it'll really get the gunk out, then fill with 50/50. I buy premix coolant so that I don't have to worry about mineral deposits, mixing coolant, or my mix going off. If I'm always adding nothing but a perfect 50/50 mix from a bottle, how could my ratio change? exactly.)
5. Replace fan clutch (or even better, replace fan with e-fan! and t-stat switch)
6. New rad

My guess is you'll probably get the cooling problems solved by #5. #6 is only really necessary if you're running a rad like mine was - corroded to hell and back.

You might as well do 1-4. Use an actual Mazda t-stat. Yes it sucks to pay $20 for something that the local parts store carries for $3, but how often do you change your t-stat? You might as well, your car's worth it.

Jon

 

I run without a thermostat cars runs just fine but in your case i would do the following

1. change the water pump
2.change the clutch on the fan
3.change the belts they may be slipping on idle and when driving
4.change the thermostat "It doesn't have to be oem" I don't run one and my temp always stays between 165 and 170
5.flush and fill the system.

Just a minor tune up on the cooling will help prolong the cooling system and futher the life on the motor if everything is done at one time

 

Rule of

Overheat @ stop and go = bad t-stat, bad fan clutch
Overheat @ open road = clogged radiator

 

ok i finally have it at my house (she broke her arm so that delayed me picking it up), i started to look at it today. one thing ive found is that the spark plugs were really black and dirty, dont think theyve been changed for a while, so im going to put in an old set of plugs from my t2. anyway, tstat didnt have hole in it so i drilled a small one. coolant looks good, like it was flushed already, ill drain some out of radiator to be sure. i want waterpump to be last resort, its not my car, and she doesnt want to put a bunch of money into it especially if it is a bad coolant seal. hopefully i can figure it out in the next few days, its been hot as **** so i avoid being out.

 

Wait what? Is this okay? I guess it makes sense, i just never thought of it, anyone else do this?

 

Running without a T-stat is not a good idea.

During winter months if you need to use your heater or defrost, you will find that they are not very efficent.

Also, without the T-stat to regulate the flow of water thru the block. In hot weather or under a load up a hill, the chances of over heating is great.

Since the person that stated this is in San Diego, which is a very mild climate most of the time. He could get away with it.

Also if the engine does not come up to normal operating temp, your MPG numbers will drop.

 

ok the hose pressurized, it only ran for 30 seconds but it was long enough to tell a difference. i need to put some gas in it so i can run it longer. but the fuel pump is making a loud noise, as is the wiper motor (it stops when i pull the fuse) not sure whats going on with that, i think i have an extra motor as well.. is the fuel pump going out too?

 

Wait, let me get my crystal ball out.

You need to see if it is a stock pump or an aftermarket pump. If it is an aftermarket like a carter, holley, or even those square Facet replacement ones, then it will be noisey.

If it is excessively noisey and it is mounted correctly with the isolator bushings then the fuel filter may be clogged or there may be a place on one of the hoses that is cracked and it is sucking air. Which means it would be cavitating.

 

ill have to do that tomorrow, hopefully ill get home at a decent time and it wont be 105 degrees (like its predicted to be)

 

so i let it run earlier for 25 or so mins straight, just sit there and idle, even turned the ac on..hottest it got was middle of the temp gauge. that sound right?

 

That's about where my temp guage sits with the A/C running. Little under 1/2 way. Barely higher than without the A/C.

 

i think it ran long enough..i mean if its not overheating after running for 25 mins and not moving anywhere then it shouldnt overheat correct?

 

Should be good, unless there is a problem inside the radiator. Flow is much slower idling, than when driving.

 

the idle is a little off but i think its due to it being cold and older gas (had sat since march, and also was almost out as well)) took a few mins to get the old gas out and the new gas to the carb. it actually ran really good, just the choppy idle sometimes. didnt get a chance to check hoses, because it was getting dark. any pointers?

 

The hoses under the beehive are very prone to getting oil soaked. Check those real good. Other than that, just look for wore, cracked or very soft hoses.

 

well unfortunately i think the front rotor is bad, low compression. it had gas on the plugs, and i cant get it to go over 50ish psi on a comp test. rear is fine. i dont know what else it could be other than a stuck seal. and i guess i should squirt some atf in there to see if that helps any..

 

Some people had success with seafoam