Well I finally solved the overheating problem, or rather, it solved itself. I'm positive it was just an air bubble. But now the car is running too cold! While driving it is at maybe 1/8th of the gauge. The heater blows lukewarm air... and I don't even remember the last time my E-fan kicked on. If it can't be fixed I'm not worried, rather it be too cold than too hot. But since it's getting cold quick I'd like to have some sort of heater. Thanks to anyone that can help.

 

thermostat stuck open?

 

You need to get a temp gauge with numbers on it so you can be sure. The stock H L gauge has been known to trick people into overheating their stuff.

 

When I removed my thermostat for a week, the car wouldn't ever register as being even a smidge above C. Seriously, it never heated up, ever.

Generally, you want 1/4 to 1/3, as you most likely already know. I, too, recommend getting a real temp guage, with actual numbers.

Are you running the Mazda OEM thermostat? Is it operating properly? (Is it old? If so, boil test it as per the FSM)

Not many people have the problem of it running too cold.

 

How do you know it's "too cold"?
What makes you think 1/8...1/3...1/2...1/4...whatever is too cold?

Get an aftermarket water temp gauge and give us hard numbers.


-Ted

 

he also says the car has no heat so a thermostat is a very easy thing to change- see if it clears up your heat issue. Easier to change and deal with then installing a aftermarket temp gauge. Pick one up at the dealer and it will also include the gasket.

I have 3 different temp gauges in the car including the stock one, the stock one works just fine once you know what 1/3, 1/4, etc.. means

 

btw I never, ever had a air bubble problem in my s4 cars, only since having this s5 TII motor in the car did I have to deal with air pockets.

I picked up one of these funnels to burp the air out pretty easily.

 

1/8 is normal when you have a lot of cooling even w/o the fan. That's 180F if your gauge is working, the temp of the thermostat. The fan clutch temp is a little higher, so around 1/4 is more typical. Get an actual measurement like everyone said. I'd also replace the thermostat with OEM if you haven't already, just for kicks. I'd do that even if everything was good, and I bet it is. Maybe you have heater blockage or a stuck air control door or air bubble in the heater core or maybe it's really cold out, cuz' mine gets friggin' hot even when the temp needle has barely moved.

EDIT: I also have the above funnel, it's simple and awesome. Insert, fill, start car, walk away, come back, done. No endless effort or not quite getting all the air out or etc. like other methods.

 

on my stock gauge 1/3 is about 190 degrees, when the car was NA it was lower then that, more like 1/4 and the car ran 180.

 

I just replaced the thermostat with an OEM one (there was an OEM in it before but...) about a week ago. I will try to get some real numbers and get back to you. I think what might be happening is this: When I installed the Efan I pulled the rad and replaced all the old foam that had turned to powder. I also put foam strips around the edge of the fan shroud. So I'm guessing ALL the incoming air is going through the rad, as opposed to how it used to. And it has been really cold lately. I get off work at 5:50am and its been around 30°-40°F on the drive home.

 

what kind of foam did you use?

 

those funnel things are sick, I just got one recently and I used it on an FD and my dad's corolla after changing the water pump. it makes getting air bubbles out easy.