i have an 86' made single turbo. car runs fine no leaks, but when I look at my microtech its giving me a reading of 98c but my stock water temp gauge is barely in the middle. i get a reading of 180f on the block and on the rad but for some reason the water neck is reading 205f which of course is where the water temp sensor is. no boost, brand new motor. tried with 180 thermostat and no thermostat. still reads 200+f on the water neck. what could be the cuprit?

 

Air Pocket

 

I thought I already got rid of all the air how long does it usually take for an FC.

 

still same problem only the filler neck/waterpump housing overheating 205f, radiator reads 170f and engine reads 180f. have these symptoms ever happen to anyone else. gonna take the hole assembly out today and see. anyone out there now what might be causing thing water pump is new, fan clutch is new.

 

what about the sensor?? did you check it?

 

have tried 2 new sensors nothing. I have a temperature reader and the neck assembly area is the only place thats getting hot 205F and the rest of the car is 170-180F except for the turbo of course.

 

HMM???? maybe the heaty from the radiator is causing that ?? chek that out?

 

Do you have a mazda OEM thermostat in it?

 

first of all, 98 C is not "overheating." Not by any stretch. The cooling fans don't even come on until 98 C on the Rx-8. You're not going to damage anything running at 98 C, but I do understand you wanting to run lower temps if possible.

Second, the factory thermostat is a "180 degree" unit. It cracks open at 82 C per the cooling section of the FSM and comes open fully at 95 C. Almost every rotary since the 12A has had a thermostat like that.

Third, what is your radiator and cooling fan setup?

 

BUT something is wrong because is not supposed to go over 185 atleast

 

Doesn't the stock S4 temp gauge normally read in the 1/4 range?


Nonsense.
In stop and go traffic conditions, running 190-195° is totally normal and in fact, is just how I set my efan controller to work.

 

copper radiator, plugged the t-stat and with the weather at night there is no reason for the car to get so hot cruising, only taking the rpms to 4K with NO boost. also note this is not the first time I have the car setup in the same way, just the first time this has ever happend to me. have run similar setups like this in the past with no problems.

 

bump

 

took the assy out nothing clogged, water pump ok. pressure checked the sysyem ok. next flow check the radiator. any thoughts?

 

What do you mean by "plugged the t-stat"? Try the OEM thermostat, not a stant or whatever. What do you have to lose but a couple dollars and it very well may do the trick. Also, my s4 doesn't get to half way on the stock gauge, more like 1/4 so I would want to find a way to lower temps too.

 

Are you using the same device to measure at all three locations? If not, start out by doing that as you can have varience of measurements from one device to another.

I would also change out the thermostat as it is about $14 and then at least you know it is working correctly.

Let us know the readings using one measurement device.

 

i have tried with t-stat and without one, same temps. same device 3 locations 205 on the neck. 170-180 on both the rad and engine.