Razor61

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That is indeed rare Malc, every LS400 I have looked at over the years has had water ingress in some form or another. i.e. boot seal, sunroof drain pipes not located correctly, antennae drain missing or draining into the boot, holes in the rear inner wings to name a few. Some worse than others, 'swimming pools' in the boot (wheel well or the pockets at the side) to 'tell tale signs' that water has been present at some point like the spare wheel in a mess with corrosion and white crud on the inside of the wheel. Maybe not puddles of water but condensation and dampness means there is moisture present somewhere or has been.

Car is always at a slight angle on the drive, sloping to the rear so water doesn’t pool. Maybe the capillary action of the water working its way down to the problem area happens or is accelerated when the car is moving, motion and air movement maybe. I vaguely remember reading it somewhere and the more the car is driven in all weather then the higher the chance of the ‘classic’ leak. I’ve soaked the boot and around the seal with lots of water and nothing seems to happen until the car has been driven.

Thanks, I'll be checking more often now. Yeah, I think you are on the right track with the sunroof drain/s at the rear or something and 'rodding' it with one of those flexible things with a brush on the end may do the trick. I think the Car Care Nut described the sunroof and drains as 'a controlled leak'. Dropping the roof lining and panels along with all the boot linings is probably the only way to get a good look at what's going on and get to the rear drains to rod them from the top down, I'd prefer to rod them from the top down rather than pushing any crud into the sunroof area inside and then it gets washed back into the drains. Maybe the rear drains can be accessed from the top using a flexible rodding thing with the sunroof open or partially open and some of the sunroof 'garnish' removed.

I know this subject has had a lot of attention. However, I just wanted to share my experience of this and it may help someone else. As documented in another post about my current car over the last 2 years or so, the boot was leaking into the spare wheel well when I first bought the car. I removed the old seal, cleaned, sorted all the rusty areas (the lip in the boot lock area was quite rusty with a small hole) and then painted the lip areas and fitted a new boot seal (still available at the time) Lip in the boot latch area after painting etc and before the new seal: I left all the boot trim out the car for quite a while to make sure it wasn't leaking. All good and I've been in and out of the wheel well to get the locking wheel nut on lots of occasions over the last 2 years. A few weeks ago I went into the boot under the floor to get the locking wheel nut, to my surprise and horror the area was very wet and the cardboard box for the locking wheel nut was soaking. Removed everything and left it all to dry, it wasn't a swimming pool in the wheel well but it was wet and the spare tyre was all wet . First reaction was, maybe I have been too vigorous with the power washer when rinsing off the snow foam when I washed it. So I left everything out of the boot and washed the car as normal, looked in the boot, it was dry and I couldn't see any water so it wasn't the power washer rinsing and 'forcing' water into the boot. I left the main plastic boot trim off the car so I could get to the boot lid catch area to see where the water was getting in, during the last few weeks I kept checking and sure enough it was leaking in behind the boot lid catch area, running down onto the wiring bracket and dripping into the wheel well. So it's the classic place for the issue. The dilemma was, do I remove the boot seal and 'seal' it all with something? It's a new boot seal, although it's 2 years old, and I didn't fancy that idea at all. I figured that my issue was the lip around the boot latch area that was rusted in the beginning, it wasn't great when I got the car, and isn't sealing correctly even with a new boot seal. Long story short, the lip wasn't flat in this area so - seal completely removed - straightened the lip, cleaned all round the boot lip (it's shocking how much crud accumulates in 2 years), refitted the seal and left it off the affected area round the boot lock - applied some black CT1 sealant to top of the lip in this area - pushed the seal back on and applied a small amount of CT1 on the inside and wiped off any excess. I prefer to use CT1 because it remains pliable and, in my opinion, is the best stuff to use on rubber seals/trims etc. because it sets like rubber. Pic below shows the area. Few weeks have passed with washing, driving and bad rainy/stormy weather. No leak so far and I'm pretty sure I would have seen anything leaking in. I also pulled the seal away further along periodically to see if the water was creeping along but it was all good and dry. While I was at it, I also re positioned the boot seal so one of the notches on the outer side of the seal was in line with the centre of the boot latch, something I saw on the Car Care Nut channel for the 600,000 miles Lexus. I had previously positioned the 'join' in line with the centre of the boot latch with the 2 x notches positioned equidistant along the bottom. Maybe the boot seal wasn't in the correct position, either way it looks ok now but time will tell and I thought is was cured 2 years ago.

£330 incl shipping for both motors from Amayama, plus the duty and taxes. At a guess around £400 - £430 all in. Some used motors on eBay are £100 + each so it’s not bad imo

Found this info from another post on here, makes sense and maybe the LS430 radiators were/are more susceptible to internal corrosion if the coolant isn't changed regularly than the LS400. According to the maintenance schedule, and I stand to be corrected, the coolant should be changed every 2 years or 30,000 miles but how many LS400/430 owners do this or have this done (apart from taking it to Lexus for the correct servicing at correct intervals) I certainly 'didn't' do this. Regular oil and filter change every 6 months, regular brake fluid change every 2 years yes but never thought about the coolant change every 2 years. It was around 2 years ago that the coolant on my LS400 was changed when the timing belt and water pump was done, I should change it as soon as possible I guess. £23 per 5 litres of coolant won't break the bank. Topic quote: The secret to having no problems with the transmission cooling on an LS430 is to make sure the anti-freeze is up to strength and is less than 5 years old at all times. The anti-freeze contains the corrosion inhibitor that stops the cooling pipe in the radiator rusting through and filling the gearbox with water! Topic:

Just one other possibility for this - the front strut rod bushes. Apparently this can cause a vibration around 60/65mph. Quote from a Buyers Guide on Club Lexus: Strut rod bushings, every 100k miles. Symptoms are: clunk when you first tap the brakes (you'll hear it in parking lots), slight vibration when going 60-65 mph or a shimmy under light braking from highway speeds that will be felt in the steering wheel instead of in the pedal like warped rotors normally would. https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/1019550-the-unofficial-ls400-buyer-and-owner-s-guide-2024-a.html

The one you need is a different part number to the 94-2000 LS400 so even if you have one for the MK3 it’s not the right one. Just buy the right one and have it fitted, they don’t cost ‘an arm an a leg’ and it’s probably goosed anyway.

I think you know where you can get one………….Amayama or LPD or your local Lexus dealer.

Rear engine/transmission mount maybe? Part# 12371-50010 and my advice is to just change it.

Regarding the door check assembly, the drivers door never shut correctly and when closing it ‘normally’ it bounced - no matter what I did adjusting the striker plate. It shut better after replacing the door check assembly though, I’m not saying it should be like a Rolls Royce but should be better. So this morning I adjusted the striker plate again, this time I got the door to shut correctly no problem at all. It wasn’t a major issue at all but rather a very annoying issue and chuffed that it’s sorted. Issue was the door check assembly itself, I couldn’t see how the broken bit on the body side could cause this so I removed the rubber boot on the old door check assembly and there was broken bits of plastic, a couple of metal plates detached and the end of the metal arm was bent. Looks like one metal plate in the picture but it’s 2. I guess in the past the wind has caught the door and damaged the assembly at the door side and the body side. Fixing one issue at the door side (the cut down pin and broken plastic) with a new check assembly has fixed the door closing issue, now I know it’s all related. Passenger side has the same door closing issue, body side pin and cover is fine but it may have the same issue at the door end. I’ll order a new one next time I order some parts from Amayama.

Having used the product, I'm of the opinion that the compound will remove non-permanent owner applied coatings like Rain-X or other similar products. I didn't 'scrub' the glass with a lot of pressure at all, in fact far from it. Slight pressure and a few passes, horizontal then vertical, just like buffing the paintwork with a DA polisher or clay barring it and job done. But 'if in doubt, leave it out' would apply.

It does the job very very well and I was surprised. I watched the YouTube video below about 'Hyper Cleaning' the windscreen which was interesting. I didn't fancy using wire wool on the glass or windscreen though but looks like it works if you want to take the risk. https://youtu.be/ihCK_hLSD4I?si=ycxH9SEfhcbw5Cpu

Not specific to Lexus LS models but the Glass cleaning compound and then the treatment stuff below works really well and worth using in my opinion. It's not exactly cheap but it's worth it. I've used all sorts of products and methods on the glass over the years, cleaning normally, clay barring, glass cleaning foam, Rain-X etc. and combinations of, this is the best stuff I've used so far. The stuff: Soft99 - Glaco Glass Compound Roll On glass preparation cleaner, 100 ml - Glaco Glass Compound Roll On, glass preparation cleaner, 100 ml - Soft99 (soft99store.co.uk) Cleans the glass really well, use on the windscreen and the rest of the glass. I've used clay bar in the past which does the same sort of thing, this stuff is easier to use and works great. I had already used this on my LS400 windscreen so used it on the IS250 at the weekend. This car had a new windscreen a couple of years ago. I have cleaned used Rain-X on the IS250 windscreen but when it rained you see the water 'clinging' to the areas where the wiper is active. Difficult to explain but it wasn't right considering it's a relatively new windscreen and the Mrs kept saying new wipers are needed even though they are pretty new. After using the Glass cleaning compound, washing it off and rinsing, the windscreen was 'like new' and it had removed every bit of contamination and any previous coating applied, i.e. the Rain-X. Soft99 - Ultra Glaco liquid wiper, 70 ml - Ultra Glaco, liquid wiper, 70 ml - Soft99 (soft99store.co.uk) Easy to apply and works great, it doesn't repel the water as good as Rain-X I've found but it's supposed to last up to 12 months so will see. I thoroughly cleaned the wiper blades and applied some of it as well, this was recommended by someone for Rain-X and stops any juddering and reduces smearing apparently. So, windscreen done on the IS250, worth all the effort and worth every penny. Non of the 'water 'clinging' to the areas where the wiper is active' after being done. LS400 all exterior glass done, cleaned and coating applied plus the interior door glass cleaned but not coated with Ultra Glaco liquid wiper. Glass literally looks like new. More work for the door interior door glass cos you have to wipe it off thoroughly rather just rinsing it off with a hose. And again, worth all the effort and worth every penny.

Nice one Phil, I may coat the new doughnut with lacquer before I fit it. I'll follow your method on the one I take out and then I'll have a spare or sell it. iirc a new one in the UK is around £100 I think, £30 from Amayama and I ordered it along with other bits like the door check assembly and some clips. I wish I'd noticed the door check bracket cover missing though, I've ordered a new one from Lexus Bolton.

New OE radiator if you want to prevent anything but people will have reported any ‘LS430 type issues’ with the LS400 I would think. It’s a good idea to replace the radiator anyway and flush out the cooling system with an older car. The radiator on my car had been replaced otherwise I would have replaced it.

Nope, they are all the same design as far as I can see. The early cars may have separate couplings on the radiator for the trans fluid pipes.

You shouldn’t be put off, get a ‘good one’ while you can😉 What I would say though, rust/corrosion is the #1 enemy. I know from experience the places to look for signs on the series 2 aka MK3 and series 2a aka MK4. A ‘good one’ doesn’t guarantee it will be trouble free though, it may be trouble free if it’s just ‘run’ but time will catch up. Chances are the suspension and brakes will need attention whatever car you buy and will cost a bit depending on how far you want to go.

Took some pics of the door check assembly. Looks like the door check assembly isn’t ’handed’, the same assembly fits RH and LH. There is a plastic cover over the bracket on the body side, didn’t notice this was missing until I looked at the passenger side. Another bit ‘missing’ which I will purchase of course. Drivers side after new assy and new pin Passenger side

Correct, why the LS400 didn’t suffer the same issue is open for debate. I have never owned a LS430 so can’t comment on why LS430’s suffered from it. Maybe it’s down to the make/type of radiator or where the connections to the radiator are located.

Oil and filter - done Fit new drivers door check assembly - done with new pin. Door card and speaker removed to do the job. Plastic at the body end was broken, pin was cut down so someone has been there before. The inner core is metal so door wouldn’t fly away. Washer level sensor started working again so left that for another time, truth is I forgot to do it when the wheel was off to check the suspension😀 Check all front suspension - done. Can’t find anything loose or worn. The biggy and most important...........................check if the transmission fluid cooler is built into the radiator or is separate and take pictures - done. Trans fluid cooler is built into the radiator. Pic below, sorry about the rusty bits with paint coming off. This will be rectified as soon as possible.

Jobs planned for over the Easter weekend: Fit new washer level sensor - purchased from Amayama - maybe the sensor is sticking or something but it's getting a new one. Fit new drivers door check assembly - purchased from Amayama - the arm is split on the body side where it fastens with the pin. Oil and filter change Check all front suspension and make sure all is tight and nothing slightly loose - car has developed some suspension noise over speed bumps. And then the biggy and most important...........................check if the transmission fluid cooler is built into the radiator or is separate and take pictures🙂

As said earlier, I’ll be checking at the weekend when doing an oil change and will take some pictures as well for evidence either way😄 I thought the exact same thing a few years ago - there is a trans oil cooler listed so it’s separate - then Phil (Ambermarine) clarified that it’s built into the radiator. Can’t remember now but I’m pretty sure I checked on the car anyway.

I was always under the impression the LS400 does have a combined radiator and trans oil cooler like the LS430, not seen a separate trans oil cooler on my current 98 or the 95 I had. Will check at the weekend for sure though when doing the oil change. I think the illustration may be for an option of one or it’s fitted for different markets.