Now I'm not sure how wide spread this problem is but I've had it on a mk I and a mk III and the mk IV. Having tried all of the solutions drilling holes and bunging silicon in etc nothing worked for me.
But this as first described here in the lexus forum was the solution.
Rubber profile sourced from Sealsdirect, they can provide a very close match for just about any type of seal found on cars and profile (ETS59) worked for me.
That profile is not as chunky as the standard and allows more water to escape in the way that it should and not slop in as you go around a corner.
The original part is/was prohibitively expensive from Lexus but this solved my problem for a fraction of the cost.
This can be a real pain.
If you look in the manual It is possible to set a security code on your Mk IV LS400 satnav. That is all well and good as long as a) You can remember it and b ) Pass it on to the purchaser when you sell the car.
Failing that at some point you will encounter a locked screen with no means of using the satnav etc.
I fail to see the point of setting it really but some people have done and a new owner is presented with a problem. A lexus dealer will do it for you but they are quite naturally going to charge you labor for the privilege.
I had this problem and I found this solution on one of the forums (don't which one as i would credit it here) and it worked for me.
Turn the ignition switch to ON (warning lights etc illuminated)
Press the CLIMATE and AUDIO switches at the same time and turn the HEADLIGHT CONTROL SWITCH in the following sequence:
OFF-SIDE LIGHTS-OFF-SIDE LIGHTS-OFF-SIDE LIGHTS
The SYSTEM CHECK then displays on the satnav screen wait till it finishes.
Once all the function checks display OK then press MENU and the DIAGMENU will be displayed
Starting with the AUDIO button, follow this sequence:
AUDIO-DESTINATION-AUDIO-DESTINATION-AUDIO-DESTINATION
The SECURITY menu will then display.
Using the displayed keys enter 440215 and press ENTER and it returns to the DIAGMENU.
Switch the IGNITION SWITCH to the OFF position.
Done !
Well it worked for me at least.
If for some reason you do enter a new security code write it in the book somewhere, otherwise the next owner will have the same problem.
This is common on MK I and Mk II LS400's, I haven't seen it on the Mk III or the MK IV it is caused by faulty capacitors on the PCB's. Capacitors deteriorate with age, some last a lot longer than others.
A solution was described here (post 5) on the UK Lexus owners club LS400 forum.You need to be both brave and skilled with a soldering iron to do it yourself, but I managed so it can't be too hard really.
There are several companies around the net that will do the job for you, often advertised on eBay etc.
I just love this little party trick, it is in the owners manual but I missed it. This works on my UK spec mk IV Lexus LS400 not sure about the other models but it's worth a try let me know if it works as I didn't try it on my other cars.
Press and hold the unlock button on the key remote and all the windows and the sunroof open, press and hold the lock button and they all close.
Kept me amused for hours and useful if you are in the house, have left the car windows down a bit and it starts raining also on a hot day you can open it all up as you walk towards the car to cool it down a bit.
Not really a tip but I'm often asked what the LS400 DHP or Dynamic handling pack is (my car has it) this was offered as an option in the UK only as far as I know and only on the Mk IV it was a dealer applied upgrade to include.
Spring compression rate + 10%
Height -10mm all round
Rear anti roll bar + 1mm to aid turn in
17 inch wheels
Tyros Pirelli P Zero 245/50x17
Making the ride firmer than a standard car. The car looks better in my opinion mainly due to the 17 inch wheels, the originals are rather bland. There is a noticeable compromise in comfort though you know about the bumps and pot holes a bit more but not really too bad.
There are various opinions on the cam belt service period for a Lexus LS400 and please take the advice of your Lexus dealer on when to change it.
However the manual says change at 63,000 miles but doesn't put an age limit on it. Opinions vary between 6 and 10 years i'd be going for 6 years so if your car hasn't had a change for over 6 years it's time to dig deap and do it now.
On the Mk I, Mk II the engine is none interferance, that is if the belt did break there is enough clearance for there not to be any damage, at least in the combustion chambers. I've never actualy heard of one breaking but prevention is better than a cure.
On the mkIII & Mk IV it is a different story, again I have never heard of one breaking but in 1997 the mk IV came out and the engine benefited from the VVTI system but this ment that the engine now will crunch it's valves if the belt did break, so beware.
This generally occurs when the main battery hits low voltage.
It will persist until the error codes are reset by a dealer.
Alternatively you can usually clear it by completely disconnecting the main battery (remove + terminal) for a few minutes, the code will then often clear.
The Ls400 makes a good tow car, plenty of power and it's heavy I have towed a 1500kg caravan with one over long distances with out problems.
As far as I am aware the original equipment towbar from Lexus is no longer available.
So unless you can find a second hand example an after market bar is the only option.
At the time of writing Watling Towbars seem to be the only company making them in the UK.
They make a several bars to fit all models up to 1998 the bars will fit models after 1998 but they are not type approved for cars registered after the R registration.
It is advisable to fit a transmission oil cooler if it is intended to tow heavy loads.