Aftermarket Coolant Temperature Sensor - Where To Install?

Phoenix7 · 08-10-2008, 12:46 AM

Ok, so I'm looking at the Hitman site to get my Haltech installed and I was wondering on your input.

I am going to Follow Mazda's instructions and gut the thermostat so water is constantly flowing through the cooling system instead of waiting for it to reach "Open T-stat" temps.

If I do this can I install the coolant temp sensor after the thermostat instead of before? The temps will be the same before and after the gutted T-stat, right?

Here is how HITMAN says to install it:

BTW, I already have an efan and thermostat switch installed so the fan will come on at the right temperature.

hIGGI · 08-10-2008, 01:59 PM

afaik, u can get coolant temp sensor with same thread like stock , and just use original location......best idea imho

Phoenix7 · 08-10-2008, 02:05 PM

Hey Higgi, I also got your email. I"ll make a thread for both the OMP and TII ECU. I have an N370 but you need the S4.

Phoenix7 · 08-10-2008, 03:14 PM

So Install it here (#10)?:

Would you recommend I do the same with oil pressure?

Max777 · 08-13-2008, 10:24 PM

I was wondering this exactly the other day... I want to install a oil press. and coolant temp gauges, and was thinking to just put them in stock locations...

but then, doesn't the ECU use those signals to monitor the engine? Also, if you get a wideband, do you put it into the stock location and disconnect the stock one? Doesnt the ECU also use this sensor?

So yeah, exactly what ARE we supposed to do? I've been a little confused with all the info out there.

PS: sry for hijacking the thread btw.

Phoenix7 · 08-13-2008, 11:20 PM

you just undid all your wiring. Figure out a way to go standalone. Start saving! You can contact ClassicAuto about his E6x ECU too.

Boostmaniac · 08-14-2008, 11:58 AM

Phoenix, DO NOT take out your T-stat for any reason. There is a write up either here or the other site outlining why this is a bad thing.

Phoenix7 · 08-14-2008, 12:15 PM

I was just going to gut it like Mazda recommends. What would removing it do? I don't have access to the evil forum so I can't search over there.

classicauto · 08-14-2008, 02:34 PM

Leave the T-stat intact.......you could gut it or remove it, but for street use, I'd leave it be.

Mount the temp sensor in the back of the water pump where your first post's picture shows. The Haltech's sensor can be drilled and tapped into that spot, or as Higgi says, there are sensor's available with the same threads as the stock sensor. Some people say you can even use the stock sensor.....but when I did it I saw no reason not to use the new one they supply as opposed to a 20y/o sensor.

I found that spot to be pretty even with the factory location of the temp gauge sender (beside the oil press. sensor) so I think it works great. You could really mount it anywhere, but it works fine there.

NitroRacer · 08-20-2008, 07:02 PM

You can also look into mounting under the alternator. drill and tapp the thread size your using for the sensor.

misterstyx69 · 08-24-2008, 03:13 PM

I don't know if this is your "cup of tea",But I got a Rad hose Sender thingie(and installed it,so not for sale)..heh..it looks like a T for the Upper rad hose.and it has a sender thread tap on it..I put a Coolant sender on it and Cut my Rad hose in half and Voila!.Once the thermo Opens..84 degrees celcius.

Phoenix7 · 08-24-2008, 03:51 PM

well, that's why I was thinking of gutting the t-stat so the water is flowing at all times, I could then install the sensor anywhere (like you did) and then turn the E-fan on at the right temps.

If I install the sensor in the stock location then I'll leave the t-stat alone since it'll be at the point where the water is the hottest.

Shainiac · 09-02-2008, 01:33 PM

Its virtually impossible to use a mechanical sender with the standard 1/2" NPT fitting before the thermostat. You could use a 3/8"-1/2" adapter, but itd set the probe substancially out of the coolant path. Since most electronic gauges are 3/8" NPT, so finding a descent spot for that isnt a problem. What I chose to do was weld the 1/2" fitting for the mech gauge to the thermostat neck. This puts the probe just above the thermostat, but directly in the flow of coolant. I get quick and consistant readings there once the thermostat has opened. Until the car is warmed up, I just keep my eye on the OE gauge. Here is a picture of how I mounted my sender.

Max777 · 09-02-2008, 03:55 PM

what if you want to just use the stock sensor but want to wire in an aftermarket gauge? can you splice the gauge into the wiring harness then?

Shainiac · 09-02-2008, 04:46 PM

Are you talking about the stock sensor in the rear iron below the oil filter? It would be a one in a million chance of finding a gauge that would have the same voltage to use the OE sender and still be acurate. The threads on the stock sender are BSPT (British Standard Pipe Thread). Most common gauges use National Pipe Thread, so you cant even use that location.

08-13-2008, 10:24 PM	#5
Max777 Pirate Join Date: Mar 2008 Location: Central IL Posts: 1,323 Rep Power: 19	I was wondering this exactly the other day... I want to install a oil press. and coolant temp gauges, and was thinking to just put them in stock locations... but then, doesn't the ECU use those signals to monitor the engine? Also, if you get a wideband, do you put it into the stock location and disconnect the stock one? Doesnt the ECU also use this sensor? So yeah, exactly what ARE we supposed to do? I've been a little confused with all the info out there. PS: sry for hijacking the thread btw. __________________ Rotaries:They are NOT that complicated!

09-02-2008, 03:55 PM	#14
Max777 Pirate Join Date: Mar 2008 Location: Central IL Posts: 1,323 Rep Power: 19	what if you want to just use the stock sensor but want to wire in an aftermarket gauge? can you splice the gauge into the wiring harness then? __________________ Rotaries:They are NOT that complicated!

09-02-2008, 04:46 PM	#15
Shainiac The Newbie Join Date: Mar 2008 Location: Indiana Posts: 17 Rep Power: 0	Are you talking about the stock sensor in the rear iron below the oil filter? It would be a one in a million chance of finding a gauge that would have the same voltage to use the OE sender and still be acurate. The threads on the stock sender are BSPT (British Standard Pipe Thread). Most common gauges use National Pipe Thread, so you cant even use that location. Last edited by Shainiac; 09-02-2008 at 04:54 PM.

08-10-2008, 01:59 PM	#2
hIGGI Rotary Fan in Training Join Date: Mar 2008 Location: Czech Republic Posts: 78 Rep Power: 18	afaik, u can get coolant temp sensor with same thread like stock , and just use original location......best idea imho

08-14-2008, 11:58 AM	#7
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Phoenix, DO NOT take out your T-stat for any reason. There is a write up either here or the other site outlining why this is a bad thing.

08-14-2008, 02:34 PM	#9
classicauto crash auto?fix auto Join Date: Feb 2008 Posts: 816 Rep Power: 18	Leave the T-stat intact.......you could gut it or remove it, but for street use, I'd leave it be. Mount the temp sensor in the back of the water pump where your first post's picture shows. The Haltech's sensor can be drilled and tapped into that spot, or as Higgi says, there are sensor's available with the same threads as the stock sensor. Some people say you can even use the stock sensor.....but when I did it I saw no reason not to use the new one they supply as opposed to a 20y/o sensor. I found that spot to be pretty even with the factory location of the temp gauge sender (beside the oil press. sensor) so I think it works great. You could really mount it anywhere, but it works fine there.

08-20-2008, 07:02 PM	#10
NitroRacer Rotary Fan in Training Join Date: Mar 2008 Location: San Diego Posts: 35 Rep Power: 0	You can also look into mounting under the alternator. drill and tapp the thread size your using for the sensor.

08-24-2008, 03:13 PM	#11
misterstyx69 .drives like MrMagoo! Join Date: Feb 2008 Location: Smiths Falls,Ontario Posts: 198 Rep Power: 18	I don't know if this is your "cup of tea",But I got a Rad hose Sender thingie(and installed it,so not for sale)..heh..it looks like a T for the Upper rad hose.and it has a sender thread tap on it..I put a Coolant sender on it and Cut my Rad hose in half and Voila!.Once the thermo Opens..84 degrees celcius.

09-02-2008, 01:33 PM	#13
Shainiac The Newbie Join Date: Mar 2008 Location: Indiana Posts: 17 Rep Power: 0	Its virtually impossible to use a mechanical sender with the standard 1/2" NPT fitting before the thermostat. You could use a 3/8"-1/2" adapter, but itd set the probe substancially out of the coolant path. Since most electronic gauges are 3/8" NPT, so finding a descent spot for that isnt a problem. What I chose to do was weld the 1/2" fitting for the mech gauge to the thermostat neck. This puts the probe just above the thermostat, but directly in the flow of coolant. I get quick and consistant readings there once the thermostat has opened. Until the car is warmed up, I just keep my eye on the OE gauge. Here is a picture of how I mounted my sender.