The Lexus LS 400 has garnered acclaim for being one of the most durable, maintenance-free, high-mileage-conquering luxobarges out there. These merits are largely well earned. However, what nobody seems to mention are two maintenance nightmares that can bring the car to its knees. I’m going to explain these issues and show you how to repair them without breaking the bank.
Before I dive in, let’s start off with a case study.
You’ve been driving your 24-year-old Lexus through the summer and it’s been working perfectly. Summer slowly transitions into Fall and everything is going great. The outside temperature starts to go down as the sentiment for the leafy season starts to heat up.
Going about your normal morning routine, you slide the key into the trusty Lexus’s ignition, rotate it clockwise and the engine turns. Only this time, something horrible happens. A split second after the familiar noise of the engine turning over occurs, a harsh WHIIIIIIR-CRUNCH invades your unsuspecting ear drums, ratcheting you out from underneath your pre-drive slumber. The engine fails to start.
“What the heck was that?”
That, my friend, was just the beginning.
You shake it off. Turning the key over again, the well-mannered V8 hums to life as if nothing happened. Huh, maybe just a fluke? Maybe. You pull out of your driveway; the cold crisp morning air stings your nose as you head down the street. As you proceed, a strange phht-phht-phht-phht noise is audible from the front of the car. Is that an exhaust leak? Where did that come from?
Over the next month the starting issue transforms from a once-in-a-while nuisance to an every-single-time occurrence. The exhaust leak has grown from a card-in-the-spokes tick to a freight train chug. The car you once put so much faith in seems to be giving up. Why is this happening all at once?
The answer is simple. The cold weather has done what it does best: it has found the weak links in your aging Lexus.
You are experiencing the starter motor and EGR (Exhaust Gas Recirculation) pipe abruptly deteriorating on your LS 400. These are items that sound so trivial that it’s no wonder why they don’t show up as a fly in the ointment for the big Lexus’s perceived invincibility.
You could probably live with the exhaust leak (although it goes against everything most of us desire in a Lexus—peace and comfort), but the starter motor will eventually die completely and leave you stranded at the least opportune time.
Both of these repairs will be quite expensive to resolve if you take your Lexus to a shop. In fact, the repair bill may easily exceed the value of the vehicle. It’s silly that a worn out starter motor and a cracked little metal exhaust pipe can basically total your otherwise well-running Lexus. However, with a few tools and some clear instructions, you can save your big couch on wheels from the scrap yard.
Typically, a starter motor will be mounted to the underside of the car, easily within view. On the Lexus? Well, it’s located here:
Nestled in the center of the engine’s “V”, underneath all intake and fuel injection components, resides the elusive starter motor. You can’t see it, it can’t see you.
(Note: It is well known that this V8 engine, known as the “UZ” among fans, along with its frustrating starter placement, is shared across many other products in the Toyota family. I’ll just be focusing on LS 400-specific idiosyncrasies.)
The EGR pipe, on the other hand, can partially be seen without serious disassembly, but there isn’t a chance that you can access the fasteners that secure it without removing a lot of components. This is because it is bolted to back side of the engine, right up next to the firewall. They do not make hands small enough for this kind of work.
The good news is that both of these items can be replaced during the same repair procedure. The disassembly required to replace the starter also grants you the access you need to replace the EGR pipe. Two birds with one stone, if you will.
When the starter motor is giving you hints that it is about to go, there is no better time than the present to replace it, even if it is a pain to do so. This job can be a bit overwhelming at first, but once you get going, the nerves of undertaking the big procedure begin to subside. Order the parts you need and rope off the better portion of a weekend to take it on.
You know you’re in for a good time when the second step in the starter motor replacement procedure is to drain the engine coolant.
While waiting for the coolant system to drain, it is a great time to familiarize yourself with how the engine bay looks in a completely assembled state. Grab some pictures because they’ll come in handy when it comes to reassembly. The goal is to make it look pretty much the same way when you are finished.
Once the coolant is drained, it is time to remove the air filter assembly, associated ducting, and all of the various plastic cladding in the engine bay. The throttle body is the next item to extract and is the first real entry into the complex stages of the job.
After that is out of the way, the intake plenum (the large bulbous chunk of metal atop the engine that displays the shiny Lexus emblem) must be unbolted and set aside.
Removing the plenum is about one hour into the repair. Only now are you able to catch your first glimpse of the evasive starter motor.
Chances are high that the starter motor has never been replaced in your LS 400. Even if it has been, it has probably been many years since the operation. This long period of time has allowed a great amount of dirt and other foreign debris to collect in the crevices of the engine. This dirt and sand is just waiting to jump into the intake chambers the second you decide to remove the intake manifold. You can try to vacuum out as much as you can before disassembling any further, but that will only get you so far. You simply can’t reach every little cavity.
To remedy this, I’ve found that spraying the dirt with a cleaning product greatly reduces the probability of it dislodging when you remove parts that open avenues directly into the critical inner components of the engine. In this instance, I sprayed down the joining edge of the intake manifold and the engine block.
Before the intake can be removed, you must disconnect two fuel delivery hard lines. Now commences fuel vapors filling the entire garage no matter how well you try to cap the exposed fuel lines. Good work space ventilation is critical here!
With the fuel system isolated, the intake manifold can be successfully removed. At this point you can now view the troubled starter motor in all of its glory. By “glory” I mean a severely petrified and neglected-looking state. It is truly a feat of engineering that the motor can be nestled down in the “V” of the engine, constantly subjected to immense heat, and still manage to work flawlessly for over 20 years.
Next to the starter motor is a long metal pipe known as the coolant bypass pipe. I wasn’t aware, but upon removing it, a volume of coolant pours out into the “V” of the engine creating what resembles to be a lake of blood. Poor car…I swear you will be mended!
Before the starter can be removed, you must unbolt the coolant “bridge” that runs right over the top of the starter. However, to get to the bridge, you must first relocate the thick plastic wiring harness casing that runs adjacent to the bridge. This can take two hours to do. The wiring harness is not designed to be moved out of the way, so you must spend time cutting electrical tape and carefully breaking open the plastic conduit. This requires great finesse and attention to detail in order to prevent accidentally cutting the wiring harness. That would be a hellaciously bad mistake. Once those items are out of the way, you can easily unbolt the starter motor.
With the starter removed and the work area cleaned to the best of your ability, it is now time to start in on the difficult task of replacing the EGR pipe.
There is no clear procedure that I have found on how to remove a damaged EGR pipe on the Lexus LS 400, short of pulling the transmission out of the car. So, I had to MacGyver-up my own method.
With the starter motor out of the way, you can see that you are more than halfway there on pulling the pipe out of engine bay. This is why it makes all the sense in the world to change both items at once.
However, this seemed like it was going to be a so-close-yet-so-far-away type of conundrum. From underneath the car I could see the remaining nuts securing the EGR pipe to the passenger side exhaust manifold. While I could manage to fit a small wrench on the nuts, there was not enough room to apply the needed force to the wrench to bust the nuts loose (he he). The nuts were thoroughly heat-seized to the exhaust system.
I left the small wrench on the EGR nuts, which I had accessed from underneath the car, and then returned top-side to see if I could visualize a new plan of attack through the engine bay. There had to be a way to break these nuts loose! I was so close; I couldn’t abandon the job now.
This is going to be a difficult one to describe, so hopefully the pictures can do most of the talking. In the most basic sense, I hooked the end of the barely-exposed wrench with the end of a ratchet strap. After determining that I could not yank the strap with enough force to move the wrench, I employed the use of a slide-pull hammer by hooking it to the other end of the ratchet strap.
I’ll be honest, I didn’t think this Rube Goldberg approach to loosening some rusty nuts would actually work, but I wasn’t going to go down without a fight. The guy upstairs must have been on my side this time around because I managed to break both nuts loose. These little victories are absolute triumphs for a lowly shade tree mechanic like me.
Once the old EGR pipe is removed, you can observe the minuscule-sized crack in the accordion section of the pipe, which is the source of the exhaust leak. Once you are finished cursing this strange looking exhaust piece, it is high time to throw in the new replacement pipe.
Unfortunately, you can’t simply bolt it in and tighten it down because the pipe has a range of adjustment. The bolt which allows for this adjustment cannot be accessed once the engine is reassembled. What does this mean?
It means you get to pretend-reassemble everything before reassembling it all for real! Awesome!
However, this beats having to take everything apart unknowingly because the pipe doesn’t line up with the intake plenum by half an inch. I imagine experiencing this disappointment firsthand would suck, so let’s all agree to avoid that situation if possible. Take the extra time, line stuff up, and be happier. With the new pipe aligned correctly and all the EGR–related fasteners snugged down, it’s finally time to get this engine back together.
The time has come to finally fit the new starter motor. I always like to do a side-by-side comparison of the troubled old part and the shiny new part to see if I can spot the reason the old one has worn out.
While severe mechanical wear isn’t visible from the starter’s outer casing, something was obviously going south on the inside of the motor. My best guess is that the solenoid that pushes the starter’s pinion gear out into the teeth of the flywheel was bad. No matter, in the new one goes.
With the starter motor electrical connectors hooked up and the mounting bolts snugged down, the main objective of this whole tear-down has been accomplished. Now let’s just hope I can get the rest of the assembly correct. The next logical step is to install the coolant bypass pipe and coolant bridge. These both require new O-rings and gaskets.
With new intake manifold gaskets laid down, I can now set the cleaned up intake manifold back into its rightful place.
After the intake manifold is secured, the next order of business is to reconnect the two hard fuel line connections and install new gaskets for the intake plenum.
At this point the finish line is in sight and the engine bay is beginning to look a bit more familiar. However, as is typical for this sort of in-depth repair, I happened to stumble across a “while you’re in there” maintenance item. The coolant temperature sensor, the one that sends readings to the ECU to determine how much fuel is fed to the engine, looked to be a bit worse for wear. If you haven’t changed this little guy out before, you might best do this. You may be surprised by the fuel economy gains you can achieve from this simple repair!
With this small side repair taken care of, it really was time to get this thing finished up. I was starting to cross into Sunday evening and I was banking on having the car finished to drive to work the next day. The next step in the reassembly sprint was to fit the cleaned up throttle body, with new gasket, to the intake plenum.
With the throttle body torqued down and all of the intake piping and plastic cladding reinstalled, the engine bay looks like it should once again.
The final step in this lengthy job is refilling the coolant system with the cherry-red Toyota engine coolant. This car takes quite a bit of the stuff but it is a surprisingly easy system to bleed. Just slowly fill from the top plug, leave the cap off of the coolant reservoir, and job done!
That’s it! So simple, right? I wish they had just put the starter underneath the car like everybody else. Oh well, I suppose there are worse things to be doing at 10 p.m. on a Sunday night.
Seeing as how I had to disassemble the upper most portion of the engine, I think it goes without saying that this sort of job would not be a cheap trip to the mechanic. Let’s see how the figures stack up when doing this repair yourself:
There may be a less expensive way to go about doing this repair on your LS 400, but it comes at the risk of doing the same repair twice. With as much work as replacing the starter motor requires, I’m not sure why anyone would go with anything less than Toyota-branded parts. For example, the cost difference was $60 between OEM and no-name starter motors. To me, the extra cost is worth the peace of mind.
The Lexus LS 400 is a car that deserves its status as one of the most reliable vehicles on the road, but as with all things, it has its drawbacks. These are not the cheapest vehicles to repair, nor are they the easiest. Repairs that may seem trivial on some vehicles can, at times, be a righteous pain on these cars.
The reason these repairs are never brought up in discussions of the LS 400 is because they are not regular maintenance issues. You don’t replace these items based on a schedule. You don’t plan on them going out or aging. Rarely are they considered “while I’m in there” replacement parts. But, you know what is also rare? A 24-year-old car that is capable of hitting 200,000 miles with minimal care and then being branded as “just getting started.”
While the big Lexus isn’t immune to growing old, it does happen to do it more gracefully than nearly anything else.