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Edit: Changing direction with this thread. Now I'm going to be comparing "correct" non-sai MEK100160 sensors that are available for the V8. I've even found some BMW sensors. Starts at post #6
Original:
I just bought and tried to install a new coolant sensor on my V8 and 6 out of 9 Rockauto lists are incorrect. The manufacturers websites incorrectly list them as fitting(which is why rockauto lists them). Here's the NGK/NTK one next to the factory plug.
Last edited by Sandman614; Aug 15, 2022 at 02:48 PM.
That seems to be the coolant sensor for the radiator on SAI trucks. My guess is that companies don't differentiate between the engine mounted one and the rad mounted one. I was looking around for the engine mounted one a while back and found it difficult to find. Haven't tried searching again but I wanted to replace it to troubleshoot my coolant temp issues in case it was reading off.
That seems to be the coolant sensor for the radiator on SAI trucks. My guess is that companies don't differentiate between the engine mounted one and the rad mounted one. I was looking around for the engine mounted one a while back and found it difficult to find. Haven't tried searching again but I wanted to replace it to troubleshoot my coolant temp issues in case it was reading off.
I didn't think about the SAI trucks being different. Searching for the non-SAI p/N MEK100160 brings up some results on Rockauto. I'd prefer NGK/NTK 73948 EF0135 but it's $80.. So I ordered Beck/ARNLEY 1580979
Starting to take some notes on the "correct" non-sai MEK100160 sensors I've bought and bought some extras to compare.
I'm comparing resistance readings, at Room Temperature in air, room temperature in water, and "boiling" about 208F, to figure out which sensors will read accurately since I've seen then read as high as 15-20F too high at and above operating temperatures.
It's not SAI related. And both sensors are/can be correct. I posted something about this a few years ago. I had an 04/04 SAI donor truck and it had the EV1 two-pin connector on the wiring harness. Naturally the sensor in the engine was the same. I swapped the engine into an 11/02 (MY 2003) SAI truck and found that the 4 pin connector on the harness would not plug into the CTS due to the exact mismatch you detail above. For me the solution was easy, I grabbed the CTS out of the original engine and installed it back into the new engine and of course it plugged right in. The part that puzzles me the most is that the two sensors have a different amount of pins. If the 04 harness only needs the two pin CTS, why does the 03 need four? I was hoping I could splice the harness connectors to use the 4pin CTS with the two pin DME harness, leaving me with two extra pins on the CTS to use with a separate coolant temp gauge.
@Sandman614, I was not able to successfully probe the pins on the the 4 pin CTS to determine how to make that happen. Maybe the ETM will shed some light on it but I never went any further. Maybe you can do a better job?
Starting to take some notes on the "correct" non-sai MEK100160 sensors I've bought and bought some extras to compare.
I'm comparing resistance readings, at Room Temperature in air, room temperature in water, and "boiling" about 208F, to figure out which sensors will read accurately since I've seen then read as high as 15-20F too high at and above operating temperatures.
First off here is my method. I made some leads that snuggly fit on the pins in the sensor and verified which two pins the harness plugs into, the 2 on the right side of the indention on the sensor side.
Ordered some sensors and measured them as shown below. I already reinstalled the Factory sensor before I started taking measurements..
The red measurements are taken on the incorrect set of pins of the sensor after realizing the AllMakes one was produced incorrectly..
AllMakes sensor being measured on the correct pins
NTK sensor being measured on the correct pins
Last edited by Sandman614; Aug 15, 2022 at 02:46 PM.
It's not SAI related. And both sensors are/can be correct. I posted something about this a few years ago. I had an 04/04 SAI donor truck and it had the EV1 two-pin connector on the wiring harness. Naturally the sensor in the engine was the same. I swapped the engine into an 11/02 (MY 2003) SAI truck and found that the 4 pin connector on the harness would not plug into the CTS due to the exact mismatch you detail above. For me the solution was easy, I grabbed the CTS out of the original engine and installed it back into the new engine and of course it plugged right in. The part that puzzles me the most is that the two sensors have a different amount of pins. If the 04 harness only needs the two pin CTS, why does the 03 need four? I was hoping I could splice the harness connectors to use the 4pin CTS with the two pin DME harness, leaving me with two extra pins on the CTS to use with a separate coolant temp gauge.
@Sandman614, I was not able to successfully probe the pins on the the 4 pin CTS to determine how to make that happen. Maybe the ETM will shed some light on it but I never went any further. Maybe you can do a better job?
Do the 4 pin sensor and the 2 pin sensor screw into the same location on the engine/same thread? I had half a thought to cut off the 4 pin connector and splice in the 2 pin connector to use the more readily available sensor. If I can't find a 4 pin sensor that will read correctly I might still go that router.
Incorrect coolant sensors..
