Engine Overheating/ Burning Oil

timbo

timbo

Greenie N00B Member
Greenie Member
So I bought my speed3 back in february and it was already burning oil, I thought it was the turbo so I swapped it for a used ko4 and I still got the same problem. I pushed it off the to the side but I've been noticing that my coolant is getting really hot, with it getting up to around 220 F on idle and 240 F after hitting boost. She's now garaged for the winter so now I'm wondering do I even bother tearing down the engine or do I start to look for a new motor?
 
You should do a few checks first before condemning the engine. Maybe the water pump is weak, maybe the thermostat isn't fully opening, there could be air in the cooling system, the fan could be operating at less efficiency. If all those check fine then get a block test kit and check for exhaust gasses in the coolant. If you're not mixing oil and coolant then it's gotta be burning it or leaking it out.

FWIW I would data log it if possible. I see massive spikes in my Miatas coolant temps in boost but the second I let off throttle they drop down to normal. I'm talking 15-20 degree Fahrenheit increase but if it was really overheating then there's no way a cooling system could shed that temp increase within 1-2 seconds of letting of the throttle.
 
Without fail every time I do a coolant flush there is air trapped in the system that has to be patiently hunted out. If you replaced the turbo I assume you at least partially drained the coolant - get a vacuum bleeder / refiller from harbor freight or rent one from an autoparts store, and redo your coolant. At the same time, get a new OEM thermostat since your coolant is empty anyways.

These cars also will burn oil which is pretty normal, wouldn't hurt to replace your PCV valve to at least rule out that option.
 
I was running datalogs for my tuner after I replaced my turbo and wasn't reaching max boost. I emptied and replaced most of the coolant after the swap as well. Also it starts to overheat the second I turn my motor on, reaching 220F+ after a few minutes of idle and would not go down from 240F after hitting boost until I shut the car off for a few minutes while the fans were still running
 
Also should mention I'm the third owner of the car and its sitting at around 141K on the dash, with no maintenance record from the 2 previous owners
 
Are you sure the coolant temperature sensor is actually reading correct? A few minutes of idle after a cold start you shouldn't be hitting those temps unless one of these things are happening:

a bad ECT sensor skewing the data
A water pump with no flow due to impeller failure
Exhaust gasses entering the cooling system

Have you ever replaced the thermostat and if so was it OE? I ran into an issue where I got an aftermarket one which looked correct. Once I started driving temps hit 220-240 and the car was overheating. I pulled the thermostat out and compared it to the OE one. Turns out Mazda 3's and Mazdaspeed 3's have different length thermostats. The aftermarket wasn't opening enough. OE is left, aftermarket right.

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Needless to say you need to run tests before just replacing the engine. Unless you wanna spend a bunch of cash to possibly end up with something still causing it to overheat when you could have fixed it for much less.
 
Hey guys need help already to the edge of selling my speed 6 i being having temp problems last lower radiator hose broke replaced it and got new thermostats put everything back together fill up turn on all normal half away after good time then went for test drive only went down the st the temp went up to 244 and stay there only went down to 241 went back and park the car let it cold down later drive it and went up again after driving it i do my on work on the car but don't know if head gasket or water pump is not smoking fans are running good don't want to replace the water pump then know that is the head gasket any suggestions or ideas before i get tire of this and just sell the car. Thanks everyone in advance.
 
Cris966 said:
Hey guys need help already to the edge of selling my speed 6 i being having temp problems last lower radiator hose broke replaced it and got new thermostats put everything back together fill up turn on all normal half away after good time then went for test drive only went down the st the temp went up to 244 and stay there only went down to 241 went back and park the car let it cold down later drive it and went up again after driving it i do my on work on the car but don't know if head gasket or water pump is not smoking fans are running good don't want to replace the water pump then know that is the head gasket any suggestions or ideas before i get tire of this and just sell the car. Thanks everyone in advance.
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Is the thermostat OEM? If not, replace it with true Mazda OEM. You likely have air in your system, did you burp it or allow it to bleed off?
 
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