radiator clogged ?
 

My s4 na a/t use to leak a little coolant at the fill point on thermostat neck ( I thought was due to a hairline crack ) . So I replaced it with my t2 spare & 16psi cap . Now after it heats up it keeps climbing in temp until it pisses out of the radiator cap ( which I thought only s5 had ) . My overflow doesnt work , even though youd think it does because I just did an oil change and noticed a bunch of coolant drops and residue just from the back of the underpan to the mid of the tranny. Im guessing the over heating im seeing (1/2 +) isnt the pump or the thermostat ( that I was going to replace today ) . Any clues or suggestions . Btw I cant take the shroud and fan off its about 15° in maine at the moment

Bunch of questions....

1) What version of the cooling and overflow tank are you using? Do you have two caps? Where does the overflow tube run from? If you installed a overflow cap where you needed a flat pressure cap it would probably leak like you described.

2) is the fan clutch working correctly?

3) I would replace the thermostat

4) is the water pump leaking? If not I wouldn't replace it

The fan clutch is failing I tested it hot . Pumps not leaking . The over flow is fed from the top of the radiator ( the line never heats up and the flow doesnt change level ) as far as overflow type I dont understand , I thought we all had the same ( stock ) . One cap is 16 ps stant . The other is .9 bar . Both are flat

Nichi ra on radiator

if your car is heating up pretty damn quick i would suggest the t-stat replacement and if you know you clutch fan is failing do that too. might want to check your system with a tester.

i my self am troubleshooting over heating. next thing i gotta check is the t-stat cuz everything else tested ok.

Mazda had a few different versions and fixes for the early 2nd gen cooling system. They then changed it all again for the 89-91s.

The cap on the radiator should have a spring on it which regulates cooling system pressure and overflow to the overflow tank. The cap on the thermostat housing / upper radiator hose area is the fill cap used to fill the system. It should have no spring on the inside of it. Which cap did you try swapping for another?

The water pump on these cars had a metal impeller that spins with the pulley. If it's not leaking or grinding from bad bearings chances are that it's fine.

I swapped the upper cap for the upper cap off my t2 . Both have springs , one is visible , the stant on top , and the nichi ra is spring loaded just cant see the spring

Argh... That's the pita part about the different versions. Mine has been updated to the "best" setup for my year. This is what mine upper fill cap looks like.

I'd really look at the thermostat and fan clutch if you know it has issues.

Is your over flow there or at the radiator ? Ill go get a cap at napa before they close . Also does anyone know if a b2200 fan clutch will work ? I cant find oe

now that just makes me wonder. not trying to thread jack btw.

i dont have a filler cap on mine where the t-stat is at. its just one piece. so it looks like your with no cap just hose to the top of the rad.

Your s5

write out a diagram of your system including where you have pressure caps located.

flat caps are fine but they have to go only in a certain spot that does not push to the overflow.

Both caps are pressure caps . Upper cap is 16 . Radiator is 13 where the overflow is fed . Tomorrow ill take the fan shroud off and see if there is the common leak under pump .

Not being condescending... so don't read it as such.

There is no common leak under the pump, if its leaking under the water pump, the pump has likely failed. The pump has a weep hole on the bottom, the sole purpose of the hole is to indicate that it has failed. If it really is leaking, like through the sealing gasket/RTV/whatever, then just pull it off and redo it. Just make sure to clean the mating surfaces thoroughly before throwing the new RTV on.

Your cap setup seems fine, even if the upper is a pressure cap, the lower will open first, and you have that hooked up to the overflow. As long as the lower is operating properly, move to the next step. If you haven't already read on here, the Stant caps aren't so reliable. The cool thing I've found is that Autozone started carrying the MOTORAD brand caps, even their thermostats. That was the OEM manufacturer for Mazda... so its good stuff.

My overflow is directly off the radiator. I don't think the cap is your overheating problem, but maybe one of your leaks and you probably want to make sure you have it correct long term. I still would look at the t-stat and fan clutch. Both could easily cause quick overheating.

The fan/clutch ain't the problem.
The OP could remove it entirely and given his ambient temps (15°), his car should idle all bloody day without overheating.
Low speed on my Lincoln fan is triggered at 195° and it hasn't come on in weeks now, even in mostly city driving. Hell, during a 3300 mile trip at the end of summer, the fan only activated three times and even then, only briefly.

So, if it's not the fan, I'd say the most likely suspects are:

-thermostat
-waterpump
-clogged/obstructed radiator
-slipping belt

Weep hole would be the common sign I am talking about . Im gonna try another clutch from a different car and see about that . Not sure if it works though . I just ordered a pump , thought there doesnt seem to be a leak . With no coolant it will be the perfect time to say my radiator is clogged ( even if it isnt ) & get an n flow

Unless aluminum can instantly cool ( which I highly doubt due to end cap surface temps ) its a clog in the radiator . The top is hot the mid and bottom are cold . Thanks guys . Now time too order an n flow xD xD

Clokker while Im ripping out the radiator , and replacing the t stat should I just replace the pump aswell ?

i would pressure test the system, if it holds fine to 13psi and doesn't bleed pressure past the cap to the overflow but does only when the engine is running it is probably an overpressurization issue.

RR

how would address an over pressurization issue?

block weld(ghetto temp fix) or rebuild

block weld only seems to work if the engine is ingesting coolant internally. if it is only pushing exhaust gas into the cooling system it is unlikely to have any effect, unfortunately.


a normally operating cooling system should never be able to breach the radiator cap pressure unless the engine is already in the red on the gauge, and you should never let it get that high.

a stuck thermostat would overheat the engine and the most likely alternate cause, a faulty water pump less so, and in the ambient condition the fan is the least likely cause. a plugged up radiator is very uncommon unless you like tap water and it has been using it for years and years, in which case it is more harmful to the engine than the radiator.

An over pressurization in my system can be easily attributed to coolant being incapable of cycling from the block into radiator . Another sign suggesting my clog would be running without cap on radiator . As the t stat heats up and opens its starts flowing , at first the over flow catches it then the stat opens up and coolant overflows . My block neither burns coolant or pushes gas into coolant . Or oil for that matter . The radiator is very cold in the center and sides and bottom . There was no leak on my pump either , but I only found that out after I bought a new one .

just saying. it's a possibility and many people spend weeks running around in circles trying to avoid it, replacing every part of the cooling system while turning a blind eye to the real problem. you can also use the pressure tester to see how much pressure is building in the cooling system and how rapidly.

overpressurization also results in coolant flow stalling as air pockets form in the cooling system and the radiator remains cold, there's no problem in having it flushed but if it doesn't cure the problem don't say i didn't tell you so. :)

yikes,

so if the system tests and holds 13psi fine, that would be good news right? no leaks and doesn't necessarily mean over pressurization? or is that still a possibility?