Where to tap for Water Temp Gauge
12-03-02, 04:11 PM
#1
Where to tap for Water Temp Gauge
Thinking of tapping Into the Thermostat Housing for 1/8NPT fitting, above the Thermostat when It opens.
Should I do this or use the existing Water Temp Unit found at the back of the Water Pump to create a Tee to mount the aftermarket sender unit Instead.
I am using Autometers Phantom 5537. What did you guys use.
Should I do this or use the existing Water Temp Unit found at the back of the Water Pump to create a Tee to mount the aftermarket sender unit Instead.
I am using Autometers Phantom 5537. What did you guys use.
12-03-02, 04:37 PM
#6
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I drilled and tapped the housing just below the thermostat (plenty of metal there to tap).. Looked over the area carefully, found a good spot, drilled, then tapped. Put some sensor safe sealant on the threads, and installed the fitting. Just make sure the sensor isn't shrouded and has a clear path in the coolant...
PaulC
PaulC
PaulC
PaulC
12-03-02, 04:40 PM
#7
Well, I dont know how big your sender is, but mine was bigger then the diameter of the housing would allow.
Plus there isnt much there to drill and tap for threads.
Your gauge should have came with a adaptor, just bring it to a welder and have him weld it on, drill a hole after and your done, it will take all of 2 minutes to weld and you will have plenty of threads to thread the sendor in. And if you ever wanted to remove the sendor for some reason you could just plug the housing up after.
Plus there isnt much there to drill and tap for threads.
Your gauge should have came with a adaptor, just bring it to a welder and have him weld it on, drill a hole after and your done, it will take all of 2 minutes to weld and you will have plenty of threads to thread the sendor in. And if you ever wanted to remove the sendor for some reason you could just plug the housing up after.
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12-03-02, 04:48 PM
#8
What would be good for sensor safe coolant? I was thinking of using RTV Silicone.
What do you mean shrouded?
The predominent reason why I want to tap Into the housing directly Is the adapter doesn't allow the sender unit to screw all the way down. When I reached the max turns, the bottom of the sender unit sits flush with the bottom of the adapter. Unless thats how It's supposed to be?
What do you mean shrouded?
The predominent reason why I want to tap Into the housing directly Is the adapter doesn't allow the sender unit to screw all the way down. When I reached the max turns, the bottom of the sender unit sits flush with the bottom of the adapter. Unless thats how It's supposed to be?
12-03-02, 05:03 PM
#9
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The autoparts store sells RTV that specifically states Sensor safe.. The reason is the threads of the sender grounds to the housing, if you gum it up with sealant and don't get a good ground, you'll have goofy readings on the gauge.
Once you pull the thermostat neck off, and look down under the thermostat, there's several areas that you could put the sender that would shroud or block the tip of the sender from being in flow.. It'd still read a coolant temp, but I feel better if the tip of the sender is in the flow unobstructed.
For example, I drilled and tapped one of the bolt holes for the air pump bracket.. while that worked, the sender didn't stick out far enough without having to grind some of the aluminum away..
PaulC
Once you pull the thermostat neck off, and look down under the thermostat, there's several areas that you could put the sender that would shroud or block the tip of the sender from being in flow.. It'd still read a coolant temp, but I feel better if the tip of the sender is in the flow unobstructed.
For example, I drilled and tapped one of the bolt holes for the air pump bracket.. while that worked, the sender didn't stick out far enough without having to grind some of the aluminum away..
PaulC
12-03-02, 05:42 PM
#10
Good point about the sealant being conductor compatable. Whats the make of the sealant you used?
I'll have to have a good look at the area, In which I am tapping to tomorrow.
I am not only going to use the smaller adapter (the one which sits flush with the sender on the bottom, when screwed In tightly) but I am going to have the bottom of the adapter flush with the rest of the housing. Doing this will not obstruct the Coolant flow.
I'll have to have a good look at the area, In which I am tapping to tomorrow.
I am not only going to use the smaller adapter (the one which sits flush with the sender on the bottom, when screwed In tightly) but I am going to have the bottom of the adapter flush with the rest of the housing. Doing this will not obstruct the Coolant flow.
12-03-02, 07:05 PM
#12
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I tapped the housing where silverrotor had the bung welded on. Plenty of metal there and the sensor is directy in the coolant flow. (mines actually the thermal switch for my e-fan)
those of you who've done the TB mod can use the nipple hole on the back of the water pump housing as a location to tap. I have an 1/8" threaded plug in mine but you could just as easily mount the sensor back there.
those of you who've done the TB mod can use the nipple hole on the back of the water pump housing as a location to tap. I have an 1/8" threaded plug in mine but you could just as easily mount the sensor back there.
12-03-02, 07:16 PM
#13
Thats the pic of my engine compartment, I guess he host it for me, again I say my gauge is a mechanical one, the sender would'nt have fit without the bung welded on, maybe a electrical gauge has a smaller sender? The total length of the mechanical sender was like 1.5-2 inches. So really the bung served dual purpose, it allowed me to get the threads I needed and it allowed the clearance I needed as well. The tip of the sender is just into the flow of coolant.
Originally posted by Jimmy325i
I tapped the housing where silverrotor had the bung welded on. Plenty of metal there and the sensor is directy in the coolant flow. (mines actually the thermal switch for my e-fan)
those of you who've done the TB mod can use the nipple hole on the back of the water pump housing as a location to tap. I have an 1/8" threaded plug in mine but you could just as easily mount the sensor back there.
I tapped the housing where silverrotor had the bung welded on. Plenty of metal there and the sensor is directy in the coolant flow. (mines actually the thermal switch for my e-fan)
those of you who've done the TB mod can use the nipple hole on the back of the water pump housing as a location to tap. I have an 1/8" threaded plug in mine but you could just as easily mount the sensor back there.
12-03-02, 09:42 PM
#15
Senior Member
Here is a pic of where my mechanical water temp gauge sensor is mounted. I paid a machine shop to drill and tap out the housing for me (cost around $40.00 vs. ~$50.00 to buy a tap I would only use once).
From what I understand that is the spot that some models of cars had a factory sensor mounted (for an aux. fan?) although I can't recall seeing it used on any cars.
The next time I have to do this to a car I will NOT mount it in this location. I found out quickly that it is inaccurate to judge how hot the engine is because it is after the thermostat and in my case does not get much water flow over the sensor (because of the length of it). I was in a hurry and did not put much thought into where it was mounted. I don't care what the temp is outside the motor, I want to know the temperature of the water before the thermostat so I can tell if the thermostat has stuck in the closed position.
From what I understand that is the spot that some models of cars had a factory sensor mounted (for an aux. fan?) although I can't recall seeing it used on any cars.
The next time I have to do this to a car I will NOT mount it in this location. I found out quickly that it is inaccurate to judge how hot the engine is because it is after the thermostat and in my case does not get much water flow over the sensor (because of the length of it). I was in a hurry and did not put much thought into where it was mounted. I don't care what the temp is outside the motor, I want to know the temperature of the water before the thermostat so I can tell if the thermostat has stuck in the closed position.
Last edited by CarmonColvin; 12-03-02 at 09:46 PM.
12-03-02, 10:45 PM
#16
I'm choosing to tap It In after the Thermostat b'c of the surface area I have to work with.
Even still, If you are replacing the Thermostat every year, with that of a genuine Mazda one, having It fail on you In the closed position Is the least of your concerns.
Finally, the stock Water Temperture Gauge, Is still equally effective to measure the temps In the Motor. Although not numerically.
Even still, If you are replacing the Thermostat every year, with that of a genuine Mazda one, having It fail on you In the closed position Is the least of your concerns.
Finally, the stock Water Temperture Gauge, Is still equally effective to measure the temps In the Motor. Although not numerically.
12-04-02, 06:01 PM
#18
Partstrader- I cant see why your sender isnt in the flow of coolant? Its telling you the temperture of the coolant before the thermostat, so if the thermostat sticks closed you will still see the temperature rise. Some people tap the waterpump housing, besides being a pain to take the water pump off to do this, you are basically getting the temperature after the thermostat, so if it sticks your getting the same temp. Its not like air flow is going to cool the coolant thats sitting in the upper radiator hose and your going to get a lower reading. A water pump doesnt cool your engine off, a radiator does, so by getting the temperature reading after the radiator you are getting a true reading. If either the thermostat or the water pump fail you will still see the temp go up, and you also get true temperature readings by sticking the sender in the thermostat housing because you get the temperature of the coolant at all times, not just when the thermostat opens.
By the way I threw my welder about $10 to weld the adaptor that came with the Autmeter CF gauge I bought. No need for any tapping.
By the way I threw my welder about $10 to weld the adaptor that came with the Autmeter CF gauge I bought. No need for any tapping.
12-04-02, 11:15 PM
#21
Senior Member
Originally posted by Rob XX 7
Partstrader- I cant see why your sender isnt in the flow of coolant? Its telling you the temperture of the coolant before the thermostat, so if the thermostat sticks closed you will still see the temperature rise. Some people tap the waterpump housing, besides being a pain to take the water pump off to do this, you are basically getting the temperature after the thermostat, so if it sticks your getting the same temp. Its not like air flow is going to cool the coolant thats sitting in the upper radiator hose and your going to get a lower reading. A water pump doesnt cool your engine off, a radiator does, so by getting the temperature reading after the radiator you are getting a true reading. If either the thermostat or the water pump fail you will still see the temp go up, and you also get true temperature readings by sticking the sender in the thermostat housing because you get the temperature of the coolant at all times, not just when the thermostat opens.
Partstrader- I cant see why your sender isnt in the flow of coolant? Its telling you the temperture of the coolant before the thermostat, so if the thermostat sticks closed you will still see the temperature rise. Some people tap the waterpump housing, besides being a pain to take the water pump off to do this, you are basically getting the temperature after the thermostat, so if it sticks your getting the same temp. Its not like air flow is going to cool the coolant thats sitting in the upper radiator hose and your going to get a lower reading. A water pump doesnt cool your engine off, a radiator does, so by getting the temperature reading after the radiator you are getting a true reading. If either the thermostat or the water pump fail you will still see the temp go up, and you also get true temperature readings by sticking the sender in the thermostat housing because you get the temperature of the coolant at all times, not just when the thermostat opens.
I may only have around 100 posts but I am not a newbie.
When the thermostat is open (because it is warm) the water pump curculates water through the thermosat, to the radiator via the upper radiator hose, through the radiator and back to the block via the lower radiator hose where it is then pushed throught the block and back to the water pump.
When the thermostat is closed (because it is cold or stuck) the water pump just circulates water through the block except for the minute amount that makes it past the circulation hole (the hole about 1/8" in dia. on the plate of the thermostat). In this case there is not much hot water flowing past the sensor and even if already warm it will not give an accurate reading of the temperature of the water that is stuck in the block (which is what you really care about).
Even if the coolant flowed in the direction you described it; How will it indicate the temperature of the coolant in the motor if there is no water flowing over it because of a closed thermostat? It would eventually heat soak and the temperature would rise but by the time your gauge reached a temperature to be concerned about the water in the block would be MUCH hotter and it would be too late.
Last edited by CarmonColvin; 12-04-02 at 11:19 PM.
12-16-02, 04:05 AM
#22
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cymfc3s......I jus got a 52mm electronic greddy temp gauge. So if I replace the stock temp sender w/ the greddy one, what do I do w/ the stock one? What about all the instruments that used the stock sender?
12-16-02, 09:35 AM
#24
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I had a Nordskogg (formerly Cyberdyne till they were bought out) water temp gauge and I put the sender in the stock hole. Did not work well. I got temps over 270 according to the gauge, but the overflow tank never filled and there were zero signs of overheating.......I dunno what the hell was goin on...
12-16-02, 10:05 AM
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If the thermostat sticks and the sender is on the back side of it you'll still get a good warning that something is wrong within the system. The block essentally all ends up the same temperature and that housing is directly fitted to a good source of heat. The t-stat housing will conduct enough heat to still run the guage in the event of a t-stat failure and alert the driver long before its too late. The air flow over the top of the engine is probably pretty neglidgible because the hood is sealed at the cowel. Any air flowing through the engine bay is being forced out the bottom of the firewall and creating a high pressure zone up where the t-stat housing is located.