I thought I'd share what happened to me today as I find it kind of funny. I also am asking for advice. My car has been running hot, a little over 1/3 of the way up the gauge (I have an s4). I haven't been driving the car because I'm new to rotary's and don't want to make a mistake with it overheating. Also I don't trust the stock gauge. I have bought an after market gauge, but haven't found a pipe big enough to tap into the upper rad hose. Anyway, so i replaced the thermostat today. It turned out the previous owner had a stant one in there. I was exited because i thought I had diagnosed the problem and out in an oem thermostat. It didn't solve the problem. The funny part is, the coolant buzzer went off. I pulled over to add more coolant. The car went a little hotter because I had turned off the engine. I let it run with the stock electric fan on. After it cooled down, it turned out the fan had drain my battery so the car wouldn't start. I had to push it into a parallel parking spot, I live in town so I had to find one. When I opened up the hood, there was a hiss from the rear driver side heater hose. I think that hose is the problem. Is it normal for the hoses to hiss, it was at night so i couldn't really check for coolant. If you have any other reasons it could be overheating or tips on stuff to check just post up. Any help would be greatly appreciated. Also, don't mistake my story for bitching, I just found the situation kind of funny.

 

Sooo many threads like this... Sorry to tell you but it could have blown a seal in the coolant jacket. It could be something small like a leak and when you run low on coolant the car gets hot. Search the forums, because there are many threads like this already, you can benefit from reading all of them. Best of luck to you.

 

1/3 up on a s4 gauge is normal. Mine will get up to half on hot days and hard driving.

 

If the heater hose is hissing at the engine end then it's probably due to the oil that drops on it perhaps. When removing the hose be careful of where it connects to the firewall as it is rather flimsy and you don't want to damage the thin metal mounting tube as well as when putting on the newer one at that point.

 

Sooo many threads like this... Sorry to tell you but it could have blown a seal in the coolant jacket. It could be something small like a leak and when you run low on coolant the car gets hot. Search the forums, because there are many threads like this already, you can benefit from reading all of them. Best of luck to you.

I have done all the coolant tests, it isn't a blown water jacket. Also the car never got low on coolant when it was running hot. The only reason the buzzer went off was because I had just refilled the coolant because of the thermostat change. I think I may be losing pressure because of a bad hose. I'm just gonna replacer all the hoses and radiator cap and see from there. Also, the coolant level never changed when I was running it before, I changed the coolant and thermostat. As to searching I have read almost all of these type of threads. Also the car has never ever been above 1/2 way up the s4 gauge

 

So it would be ok for me to run my car like it is now?

 

"Hissing" is normal for snakes and cats, not for coolant hoses.
Replace it now.

BTW, what "stock electric fan" are you referring to?

 

The stock electric fan is the one in front of the radaitor toward the passenger side of the car a little. It is used for a/c and overheating situations. I'm new at working on cars, and forgot to reconnect the ecu's temperature sensor, this is why the car wouldn't start when it was hot. I'm going to replace the radaitor hose right away, thanks for your help.

 

Radiator hose? I thought you said it was the heater hose that was hissing?

Why was the thermo sensor (ecu temp sensor) unplugged in the first place?

 

Sorry, I didn't realize you know everything already.

 

The ecu sensor was unplugged when i changed the thermostat. It is the heater hose i miss typed. And EnjoiPugs I'm not trying to say I know everything, sorry if that the way it came across. I have searched the forums a lot, and found a lot of useful stuff, I was just trying to say that I did not have a blown water jacket seal, I've checked to make sure several times.

 

that hose is a common failure for cars where people do oil changes sloppy and drain the oil on that hose, or if the oil sender unit or oil filter housing are leaking/seeping.

 

it was dark and hissing....man i would have let that bitch sit there till morning, I hate snakes, so if a couldnt see anything, shoot, i would be hissing too if i was locked up in an engine bay. lol, glad it wasnt a snake.

 

Ya that would have been crazy if it was a real snake

 

I think he has a leak in the corkscrew heater hose. Most people don't replace this one because you have to buy it from mazda an it is very expensive for a heater hose. It's probably the original hose. If I were you I would drop the $200 on all new OEM Mazda heater and coolent hoses. I have done it before and would do it again without hesitation if I feared my coolent system wasen't in top notch working order.

 

There aren't any stock electric fans on FCs. They were all clutch fans, no exception.

 

^ There is an electric A/C fan (or at least in my car there is). I know it is for the A/C but I think that is it. After my Haltech installation the damn thing runs 24/7 so I unplugged it for now while i figure it out.

 

If I find out there is a stock electric fan my head will explode.

 

Not sure about S5's, but All S4 turbos and automatics came with a small electric fan located on nose side of the radiator.

 

BTW I wasn't tryin' to be a dick or anything, I was just stating that that my car has one and it was completely stock when I got it. It only is supposed to come on when you turn on the a/c though.

 

But not N/As? Thank goodness, I was going to say if my s4 N/A had an electric fan I'd be shocked that I never saw it. Why didn't they put them on N/A's?

 

The S4 electric fan is also temperature sensitive. 207 degrees for turbos and 195 degrees for autos. There is a temp switch located on the thermostat housing which triggers the fan.

 

Automatic N/A, yes. Standard N/A, no.

 

Not true only turbo models with ABS , or autos had this . You can use this to wire in an efan too , as I did.

 

^Does it work well like that? Is the stock sensor reliable enough. Also, 10yearrx7 i know my efan ran constantly when my temperature sensor wasn't connected to the ecu, i dont know if this applies to you though as you have a haltech. I'm going to replace all the hoses when I get a chance. Can you use those cut to fit hoses from autozone or is that not reccommended