Michael88

WEEKEND UPDATE - So, the feeding hose was in good shape without significant cracking except one tiny crack on the very end. I removed the hose and gave it a good soaking with penetrating oil and let it sit. Resulting in a more resilient and pliable hose. I turned my attention to the feeder tube O ring. I removed two power steering pump mounting bolts underneath the car and remove the mounting nut in the front through a hole in the pulley. This allowed me to slide the pump forward, so I could remove the feeding tube bracket bolts without removing the timing chain cover, without moving the ABS cube, or without removing the alternator. I inspected the feeder tube and O ring fit by inserting it several times into the old pump. I concluded that either a meatier O ring was needed, or an O ring was missing in the base of the hole in the pump, or both. The remanufactured pump came with two O rings. One matched the old O ring and the other was smaller but fatter and there wasn't a match on the old pump. I found O rings at a great local True Value. I determined the second O ring that came with the pump was the wrong size and a lerger one was to sit in the bottom hole in the pump with the feeder tube on top and the matching O ring on the tube itself. Re-installed the pump on the car, and there were no leaks from the top of the pump! Ordering a new crush ring for the high pressure line and will install it soon.

Recall that I had intermittent starts and intermittent idles with a failed voltage regulator test. Two IMPORTANT fixes to share here. Firstly, LS400 has security measures inside the key itself (the key has a special cut and the transponder must be right against the ignition for the vehicle to run), and my key was not broken. No signs of cracks in the plastic or anything. During this weekends repair, the plastic broke and the key separated from the transponder. This is when it dawned on me that the key may have been the cause of intermittent starts and rough idles. I dug out my valet key (which was rarely used and stored away in new condition). The car has started every time (so far). Secondly, when I pulled the serpentine belt off to do pump work, I checked the idler pulley. It was original and it spun easily in my fingers. However, It did make the faintest "gravelly" sound and I could convince myself that it "catch" just the slightest bit. So I bought a replacement and installed it. Since then the idle has been spot on and the strange electrical blimps have disappeared (knock on wood). My unprofessional suspicion is that the slight catches and gravelly spinning of the idler pulley put variation in the timing curves generated for the computer, and the computer had trouble compensating for this. Let me know how far out in left field I am with this.

SO, if you are having intermittent starts and idles, consider using the spare key (having the key looked at) and critically evaluate the idler pulley. More to come

bradland

Glad you got the issue sorted out.
I absolutely hate the location of the ABS cube on the 98-2000 400's !

Michael88

UPDATE #2 So after a week of driving, I have noticed two ever so small drops of power steering fluid on the driveway. They appear to be from front and back of the pump, or could be pooling on a crossbar and dropping. It is uncertain. I will getting a new banjo compression nut for the high pressure hose and replacing the old one. Power steering is still smooth, idle is spot on, and I will be replacing the radiator soon. That is another problem. Over ten years the operating temp has gradually been increasing. As I mentioned, it's got a new water pump/timing belt. It runs hot at speed and has 202k miles. I found a new Denso radiator for $85, so I jumped on it. stay tuned.

Legender

Sounds like you're making good progress. Pretty soon you'll be looking for something else to work on as this will be complete. If it's only 2 small drops is it possible left over fluid from before the repair coming from the alternator after your repair.... unless you power washed everything down. Could be coming from there if you don't see a trail of fluid on the PS pump itself.

oldskewel

iTrader: (1)

On the issue about the danger of a PS failure, I'll say that once I was caught off guard in my '91 when my engine died while driving and I was coasting from a main road and making a right turn onto a side street. Since the engine was stopped, there was no power in the PS at all. I did not hit anything, and it all worked out, but the sudden change was a little dangerous - not having experience driving this car with no PS, I did not expect it to get so heavy so quickly. The main dangerous aspect (if that) was the surprise factor.

But that said, it's probably much more likely on any car to have the engine die suddenly, cutting PS, vs. having the PS fail suddenly while driving. So no, I would not worry about the PS issues as a major safety issue.

And BTW, on my '91, I used generic by-the-foot PS/AT hose on the PS reservoir, replaced the idle-up air valve with an OE one, rebuilt the pump myself using the OE kit, and installed a new alternator with a bleach bottle shield.

Michael88

UPDATE #3 - The Denso radiator I ordered arrived in a box with a large gash in in the face of it. I immediately was concerned that the radiator had been damaged, but sometimes the inside packing will be great and absorb the hit. I opened the box and found a damaged radiator. I wrapped it back up and called the shipper to refuse the package. I purchased shipping insurance just for this situation. Being a fragile radiator, it was a smart move. Don't be left hanging on a radiator shipment. Spend the $5 on shipping insurance. The vendor was spot on and a return proceeded after about an hour of calls, photos, and repacking. Ordered another OEM new Denso radiator, and awaiting arrival. The car is still parked and in great starting/running condition, just delayed. I started getting the VSC check light that many people complain about about 5-6 years ago, and it is back. I never addressed it. I believe I will try cleaning those two oil pressure sensors above the timing belts covers after installing the new radiator. Stay tuned.

Michael88

Update #4 - Another new radiator received damaged and I returned it. I don't think I mentioned this before, but I doubted that the engine was actually hot. It never pinged and popped like a hot engine would upon stopping and shutting it off. Heck I could even put my hand on the block without getting scalded, so I took it to Lexus. On the way there the heat gauge went straight to H like it usually does, but did something totally new to me. The needle dropped like a brick to Cold. After they looked at it, they "burped the cooling system." This didn't really do much for my car, but I thought I would share their technique. They said they had trouble burping these LS400's back in the day, unless they set only the front wheels on the lift and jacked it up. I know right, but anyway those who are DIY "burping" these cars be sure to have the front end lifted up a foot or so. My problem was the path Temperature sending unit to the communication box to the gauges. The temperature sending unit is on the passenger side intake and the connectors appeared brittle. Not failing though. The unit itself had a small pool of coolant around it and up to the wiring, from either a spill while filling the intake orifice or from a damaged housing on the unit itself. They blew this pool away with an airhose and told me that the unit is sending the proper temps to the computer for fuel/air mixture. The engine was not overheating and confirmed by reading on the diagnostics and a lazer temperature gauge pointed at several locations on the block. They said the Communication box was faulty, but not an easy replacement because they are specific to the year/make/model/ and options on the vehicle. So even if you find one the options from that vehicle have to be the same. The mechanic told me to check the temperature sending unit for more moisture in a month, and replace it if there is moisture (cracked housing on the sensor). He said if it were him he would drive it with a faulty temp gauge reading unless I was planning on making it original in operation. He also suggested a single drop of glue in the corner connector from the wiring to the sensor so it would stay in place, but could still be unplugged with little effort. By all means don't load the entire thing with glue. Stay tuned.

spuds

Following.....

RA40

iTrader: (6)

Appreciate your detailing this work-up. Quite helpful.

billydpowe

iTrader: (1)

update #4
I just drove up on the curb with the RFWheel....

Michael88

Yet another Update! So about 6 weeks have passed and my LS400 started giving me a no start situation after driving for about 30 minutes. As a reminder the dealer mechanic said if I get trouble in about a month to replace the coolant temperature sending unit. So I started having trouble almost exactly in that time frame, interestingly. Trying start the car, I noticed the throttle position sensor and the throttle motor were making a constant buzzing noise that wasn't as usual. I could unplug the throttle position sensor right next to the throttle cable pulley, and the "stuck" open buzzing would shut off. Then, reconnect it and no more buzzing. I put a lithium battery jumper on the battery just for good measure and it started after pumping the gas pedal 3-4 times. It ran pretty well, but I did shift into neutral at stops and revved up just to be careful not have engine die on me. Got home easily and didn't noticed much idle issue by the time it got in the drive. I changed the coolant temperature sensor. The old one appeared to be broken as the plug housing could spin all the way around, and the new one was a solid piece. By the way, be very careful not to over tighten anything doing this job. Things like throttle body bolts and nuts, and the sensor itself. If you torque these too hard that aluminum intake can take damage most likely in the form of a broken bolt, and then you are having to drill and tap or even worse a new intake. I had neither problem. Importantly, disconnect the the battery before disconnecting anything (even the air ducts which have the MAF sensor in them). The computer on my car had a fit when I did this with the battery connected. The computer needs to be reset by disconnecting the battery anytime you unplug anything. So far, good clean starts every time, but only a long series of successful starts will convince me that this car's problems are solved. Now a transmission flush and better reliablity, hopefully.

JamesRobin

Thank you for providing this update on Club Lexus' new restrictions for new members. It's good to see that the website is taking steps to ensure the safety and quality of its discussions and sales.