Engine Coolant Temperature Sensor Replacement
 

1996 Maxima. I just diagnosed my MIL light with the codes 0103 and 0908, which leads me to believe the Engine Coolant Temperature Sensor has gone bad. Chilton's book doesn't really give me a clear picture of exactly where it is. I know it is one of the plugs near the tranny stick. I don't want to get the Temp. Sender and the Temp. Sensor mixed up. Can someone tell me exactly where it is and also how to replace it, specifically, do I have to drain some of the coolant to replace it? Thanks..

Follow the upper radiator hose to the engine block. The sensor is right where the hose connects to the thermostat housing. If you car has two sensors there, it's the one closer to the engine block.

Thanks for your help! One last question, do you have to drain the engine coolant to replace the sensor?

Thanks! I have one other question, do you have to drain the engine coolant to replace the sensor?

No, you will lose some coolant but as soon as you unplug the old one, just thread the new one in the hole.

Thanks...I found the sensor, it looks like it'll be hard to remove.

Its not hard to remove. I ereplac3ed mine about 4 months ago. You wlaready found it. I bought the part and played a game of concentration to try and find the one that matched under the hood.:laugh: Remember to reset the computer after you fix it.

The Engine Coolant Sensor, I believe, I found is buried under a few rubber and metal hoses and some wires. It'll be a task to get out, considering its in the 30s outside where I am.

thanks a lot for all the input. the links for these codes provided in the stickies weren't working but lots of useful info was found. i found that all the codes descriptions are listed in wikibooks and also a few repair procedures. perhaps users who have written repair procedures for the 4th gen maximas submit theirs on wikibooks.

If you need a sensor , let me know. I have a used one that works perfectly

Make sure you leave the radiator cap on while replacing the sensor, that will keep coolant loss to a minimum. However it's probably block drain & radiator drain time anyways, it wouldn't suprise me if your coolant is 12 years old, you can check the condition with a voltmeter, take radiator cap off, place one probe in the middle of the coolant, and the other on the intake manifold and post up what you get for a reading :)

I just replaced mine list month, I removed the air intake and the air box, it only takes a minute to remove these things and makes the job a lot easier. Also remove the smaller temp sensor first, I tried this with out removing it, and broke the metal tab on the smaller one.

19mm wrench and some teflon tape. Very easy job.

http://i78.photobucket.com/albums/j9...n/S5001750.jpg

Or use a 19 mm deep wall socket (like I did on a 95 SE). Piece of cake - takes about 10 minutes.

I am very familiar with thermostat replacement but In coolant I don't nondefinitive, the location of the coolant is filled to the top of the radiator and the coolant bottle is filled to the proper level. My suggestion is following the given instructions properly to be able to avoid problems.



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Thermostat

Going to use this thread to ask some questions,

I was monitoring my ECT and ECT doesn't go up half (220 degrees). I hooked it up with scan-tool to see live data for ECT and its going top 198 then back down to 180 then up to 198 and back and forth. It doesn't go pass after 200 degrees. Could it be thermostat stuck open? or is it sensor fault?

Since ECT shows 198-180 degrees, does it cause misfires too because of open loop?

Thanks

Do both fans work? Do You have an aftermarket radiator?

Yes both fans work and its oem radiator. What is normal temperature coolant for our car?

The temperature fluctuation you describe is normal and keeps happening all the time. That's the way Nissan designed it.

The thermostat starts to open at about 180º. As the coolant becomes hotter, the radiator fans start running on low speed at about 200º. If this is able to cool down the coolant, the fans will shut off when the coolant temperature goes down to about 180º. When the fans stop running, the coolant temperature will rise and the process repeats.

If the fans running on low speed can't reduce the coolant temperature and the temperature keeps rising, then the cooling fans will start running at high speed when the coolant temperature reaches 212º. If this cannot cool the engine, then the coolant will eventually boil and the engine will over heat (around 250º - 260º).

The above temperature description applies when the a/c is not on. When the a/c is on, it works a little different.

Since the normal running temperature is by design varying between 180 and 200º, you should not be getting any misfires from this.

My personal experience is that my engine temp as read by my Ultragauge (OBD2, always on) is that the reading would change at almost every polling interval (1 second?) and sometimes change instantly from 180s to 160s. No codes. Then I replaced the original ECT sensor with another OEM sensor and the temps are now very steady and in the 180-200 range. Other than that I didn't notice any other differences - gas mileage seemed to be better initially but seems the same now.

[QUOTE=nhaven;6020730]19mm wrench and some teflon tape. Very easy job.

https://i78.photobucket.com/albums/j...n/S5001750.jpg
Do you have to reset anything after replacement?

Nothing needs to be adjusted or reset in the ecu after the sensor has been replaced.

thanks!

Thanks for your help!



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