Two weeks ago my engine (S4 N/A) overheated while I was on the highway, to make a long story short I found out it was a one of the coolant hoses on the Throttle Body. It’s the one that goes off the thermal wax down to the engine, right under the dynamic chamber. I removed all coolant lines on the throttle body, so this will never happen again. I bled all air out of my system and I installed a Cyberdyne Temp gauge. I put the temp sensor in the same spot used for the factory gauge. By the way my Thermostat is OEM Mazda and is a 180F.
So I'm worried because my readings are on the high side
Started recording my temp at one minute intervals.
At idle:
Temp Minutes
176 3
181 4
186 5
188 6
191 7
192 8
194 9
192 10
192 11
193 12
195 13
196 14
197 15
199 16
201 17
201 18
203 19
203 20
203 21
203 22
204 23
Shut off engine…
I know this is not normal, at IDLE!! WTF.
Do you guys think I might have a stuck Thermostat or bad clutch-fan?

Please HELP!!

 

A stuck thermostat may be the cause but im not 100% sure..
I would take out the thermostat and test it in some boiling water and a thermometer.
I think it shows you in the hynes and factory service modual.

It could also be something like your water pump maybe crapping out on you or a blockage somewhere in your cooling system.
I would start with thermostat first though..

If your thermostat is rated at 180* it should somewhat level off i would think when you are idling.. From your readings it doesn't look that way...

 

Believe it or not, those three small TB hoses actually help cool the system, by allowing more flow back towards the pump once the coolant's run on the plug side of the engine and is on its way back.

Most people that want to remove the wax and BAC runs install a "jumper" hose from the back nipple on the rear housing to the water pump nipple, just to keep this extra coolant flow going...

Your cooling fan's in good shape, I presume...

 

I checked my Tstat today, its good. I think it might be my clutch fan. I'll be installing a new electric fan along with my Tstat. I'll let you guys know what happens. Thanks for the replies.

 

how is your rad core?

 

ok

 

I had same problem, my car got to 245 f !!!!!!!!!! and still runs...thanx to cnc weld..( for now)

 

also try distilled water, helps alot