Hi Vidlev, we have the same model 98 LS 400 and can you send me a picture of your temperature gauge needle while you're driving. Mine also sits one hash marks above 50%. I just want to make sure that it is normal. I already change my engine coolant temp sensor and the result was increase gas mileage but the needle still on that mark. Please send it to blim2137@gmail.com. This is my retirement car.

 

I posted an image earlier in this thread showing the correct posistion of the needle.

 

Hi 400 fanboy, I saw the temp gauge needle picture that you posted, Mine stays on the next hash mark. So reading the thread, somebody mentioned about changing the temperature fuel gauge sensor. Where is it located at in a 98 LS 400? Also thank you for your reply.

 

One hash mark above 50% is indicating running quite hot. Sorry I mis-read your original post.

If it still does bother you - I would hook the car up to a scanner and just measure temperatures directly. If they're outside of acceptable ranges, then yes you can start working down the checklist. Sadly I don't know specifics about where these sensors are or how to fix them. A mechanic should be able to figure it out - or if you do your own work - investing in a shop manual for the car is a worthy purchase. Or maybe someone more knowledgeable than me can comment.

It could be many things. If the car is indeed running hot - it could be the cooling fan clutch as well.

But remember, I'm an idiot on the internet who is wrong many times, so take my advice with a grain of salt. Best of luck sir. That's my 2c on the matter.

 

I grabbed this pic which was posted by timmy0tool from another thread.
Just so the newbies know; All these parts do not need to come off to change the sensor. I'm just showing a clear view of the sensor.
Hey benlex400, you mentioned you already changed your ECT sensor. The sensor for the gauge is on the front water crossover pipe and sits right next to the ECT. It is the one with grey connector and 1 wire.

 

Hi deanshark! Would you mind if you circle the temperature gauge sensor in this picture. I know the Engine Coolant Temp sensor is the green one which I already replaced.

 

I can't with this cheap ancient phone I'm using right now, maybe someone else can do it for ya, sorry. But like I said, "It's the grey sensor sitting right next to the ECT". About 1/2 inch to the left of the ECT in this pic.

 

Here it is.

 

Interesting...the anti-lock brake solenoid block is mounted by the firewall..
There also appears vacuum actuator and lines (to right in image)
Every 1998 - 2000 LS400 engine compartment surveyed, the anti-lock brake solenoid block is located forward of engine, on chassis, near power steering pump.

What am I looking at here?
LS430?

 

The car must be an SC400 with the VVTi 1UZ-FE, I bet.

 

I'm sorry but I don't know exactly what year engine this is in the pic. Like I said, I took the pic from another thread. (about the 98 ECT sensor) This one; https://www.clublexus.com/forums/ls-...mp-sensor.html I looked at alot of pics the last few hours to try and find the correct spot that sensor is but couldn't find one.
All the 98-00 I've seen are the same as this video labeled as "replace starter on 2000-2006 LS430"; At 6:40 you can see the gauge sensor isn't on the crossover. (as in the pic above) There's a place for it but just has a bolt in it. So the pic is not from an LS430 either.

I'll quote 400fanboy from his last post; "But remember, I'm an idiot on the internet who is wrong many times, so take my advice with a grain of salt. Best of luck sir."

Sorry if I confused anyone with the pic I posted, I try to be correct with my posts. Just gotta think, "Eh, it happens to the best of us."