coolant pushing into resivoir
 

my 87 TII keeps pushing coolant into the resivoir and after about 3 days it starts pooring out of the resivoir and begins warming up past what I want it running...

I did a chemical test looking for a combustion leak into the cooling system and it showed no signs of exhaust in the coolant.. No smell in the exhaust fumes, no white smoke, good compression... One thing I did change was the thermostat, radiator cap, and water pump...

Could the cheap $4 thermostat be causing issues?? I looked it up online and I see mazdatrix has two different thermostats for s4 and s5, and this aftermarket one fits like 35 different vehicles. changed the radiator cap and tested pressures and it seemed to be holding 0.9 bar, and the cast iron impeller style pump I can't see it having much issue.

I went ahead and ordered a OEM Mazda thermostat and radiator cap, but the jokers haven't recieved them at the dealership.

Any thoughts?

Yes. Its the thermostat. Just make sure you got the 180 degree one by looking up the bunghole :)

While you're at it... go throw your current thermostat in a pot of boiling water and see if anything happens!

Alright, if it cures my problem Four Seasons will be seeing a product alert as well as a nasty note about the coolant bill they will be recieving

I dont know what Four Seasons (I doubt the hotel chain works on cars) is, but 99.9% of the people on this forum will tell you to ONLY use the OEM thermostats/caps.

I've been there myself. I imagine that if you get a 180 degree thermostat, with a jiggle pin on it, you're probably fine. Those are not provided by the parts stores very often though. You have to experiment.

Ryan,

I tried a Stant thermostat ONCE. 20 minutes after starting the car, my radiator (plastic endtanks) exploded while I was on the interstate. Luckily, I had an extra radiator at home, so a buddy brought it to me and got me back on the road.

When I got home, I threw the thermostat in a pot of boiling water. It NEVER opened. Hell, it didn't even move... Total piece of crap.

I now only use OEM.

try putting the old radiator cap back on also, if the new cap is faulty and isn't holding the proper pressure then it will push into the overflow.

if you run an aftermarket cap(almost everyone does) go with a 1.1 bar(16psi) cap as almost all aftermarket caps are weaker than their rated pressure. most cap manufacturers now recommend the 16psi as if it was OE spec, knowing their products don't work as described on these engines.

junk and debris in the radiator neck will give the same result, not allowing the cap to seal properly.

sure hope thats all it is for you . I wasnt so lucky . Same symptoms found no easy solution . My ugly truth was a blown coolant seal . S5 rebuild

ditto on the blown coolant seal!

+1

and yes if you test the stant caps by squeezing them, they vary, about 1 out of 5 actually works...

Thermostat needs the jiggle pin. Also, radiator cap causes the same symptons (if the rubber seal cant hold back pressure your overflow tank fill up)

I just had a coolant leak due to a faulty radiator cap as well. Got a stant with pressure release a year ago and it just started leaking so I went to autozone and got one which leaked after the first day of using so I returned it and purchased a Stant without pressure release. So far no problems. If that didnt work I was going to go to the dealer. So far so good.

stat
 

OEM thermostat and radiator cap solved the issue. I submitted a product alert to Murray (Four Seasons) to see if something can't be done about it, following up next week to see if the kinks can't be worked out...

Same happened to me!

almost none of the aftermarket thermostats have an air bleed jiggle pin, that is why they do not work and trap air under the thermostat.

When I did the aftermarket thermostat it had the jingle valve in it, Pretty sure almost all O'reilly "premium" thermostats have the jingle valve to release the air behind the thermostat