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TW sensor replacement tips

15 December 2008
I recently ran into an odd error in my stock '91 NSX. The error code related to the TW sensor. It appears that there are three coolant temperature sensors. One for the ECU (near the front bank of cylinders), one for the fans (near the rear bank of cylinders) and one for the gauge (near the themostat). I tested the TW sensor (adjacent to the front bank) and its resistance values weren't correlating well with the graph listed on page 224 of the service manual which likely is why the ECU kicked up an error. Before embarking on a senseless replacement mission, I decided to test out whether the sensor was truly bad and place a potentiometer across the pigtail and the car ran better. Great! Except one problem, I can't for the life of me figure out how to remove the sensor. It doesn't fit any sockets that I have for there are no edges to the sensor that fit a socket.

Does anyone know how to remove this sensor? Is there a special tool?


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That stock sensor is typically a hex. Looking at it, pull the rubber boot back, it looks hex under it;).

Thanks for the tip! I do have two other questions that came to mind, though.

1) Do you use some sort of sealant on the threads? Something like Teflon tape?

2) I realize that some fluid will leak out during the change. The manual doesn't mention it, but do I have to bleed the cooling system afterwards or merely replace the lost fluid?
Sometimes you might have to actually break the old dried out rubber cover on the 19 mm hex part of the sensor then remove it
The new sensor comes with a oring , I put a very small amount of
Hondabond on the threads and install , tighten till snug, don't over tighten !
Reconnect and reset ECM
We replace this sensor and the thermostat on all nsx that come in my shop
Hello, can you communicate the numbers of three temperature sensors, I have to soon replace the timing belt replaced and I at the same time all sensors (5M NSX 1992, 168,000 km), thank you very much:smile: