I just got an NGK ECT Sensor and my LS400 was throwing P310 so planning to swap the sensor.sensor.
some questions on who did this,
should I remove throttle body or just the plastics for air inlet would suffice?

Should I drain coolant? If so, just the left side of engine block would suffice? Just did completed coolant flush last week to purge an air bubble. Or any shortcuts? Like putting on rhino ramps and just swapping the sensor?

 

See this thread.
https://www.clublexus.com/forums/ls-...mp-sensor.html

If the engine is cool you can swap the sensor with minimal coolant loss.

 

​​​​​So I assume no throttle body removal then?

 

Don't know for sure. Take a look at your car the sensor is at the front of the engine.

 

I can't think of any reason you'd need to remove the throttle body.

 

I just removed the black plastic intake tube from the throttle body (maybe the resonator piping also) to get access. Then unplug and unscrew

 

It's pretty straightforward. I just did my 99 last night.

Pull the 6(?) air intake screws, the air filter band clamp, the throttle body clamp, and the three hoses off the intake box. Then it all comes out in two pieces. 19mm socket fit my sensor. Hardest part is removing the hoses without breaking the plastic intake. Also be careful if your ECT connector doesn't come out easily. Its better to take your time than break the connector. Mine didn't leak a drop of coolant, although I was ready to throw the new one in ASAP if it did!

 

I did it y'day. As rightly said, the hoses are the pain. My ECT sensor clip is already broken but I put new NGK sensor and its working well. I think it also solved my transmit problem of not shifting on D.
Still I gotta flush my transmission fluid.

But anyone doing this, all it takes is to remove the air intake plastics and nothing much. Mine did spill a few coolant when I unscrewed the ECT (even it was stone cold) but I did quick so less than 1/6 quart was wasted.
I used 3/4" ~ 19mm in my Tekton and it worked to swallow the plug. Would replace the ECT sensor pigtail housing in sometime.

 

 

Also appears to be that the bolts on fan shroud that is broken. Any tips? I thought I would drill a hold on the shroud/housing and zip tie on the existing hold where it's threaded.

 

That will work just don't accidentally drill into the radiator /captain obvious

 

that's what i have done on multiple LS400s.

 

Amazing how common that fan shroud is to break right at those bolts. I also have put zipties on multiple LS400 fan shrouds. Both my old 93 and 94 had zipties in that spot, and my now 93 doesn't have the shroud cuz I didn't ziptie it quick enough and got eaten up by the fan. Something everyone should take a look at, just incase.

 

I think I tend to lean on the shroud when reaching over to the engine. If that's the only weak point we've found I'd say its a great car :-) !