jaswood

First, "DEATH", makes it quite obvious that I don't know what I'm talking about. BUT. IMMHO the leaking PS fluid has absolutely NOTHING to do with alternator failures. And then DEATH goes on to recommend (St,d)ealer OEM reman...??? Obviously it will depend more on who does the reman(***) and that will NOT be the Stealer. *** Same source as NAPA, etc.

One of your earlier statements seemed to indicate that it was easier to move the water valve to the HEAT position with the cable connected if the commanded setpoint was max heat, or both vice versa. That would imply that the servomotor was holding position in the opposite mode and/or was too weak to actually move to the new setpoint unless you assisted it. Since it still would not move on its own when disconnected from the water valve my conclusion would be that the blend door, reheat/remix routing vane, inside the plenum, is sticking. Even moving the water valve manually to the HEAT position will be of little help if the blend door remains in the FULL cooling position.

What you are doing, in effect, is providing "boost" for the servomotor that's trying its best to move the blend door and the water flow valve simultaneously. I would vote for the water valve to be sticking. You can pop the drive cable off of the valve and then see if the cable end moves freely up and down with a setppoint change from COLD to HOT.

In the general case the on/off heat cycling of the headlight internal atmosphere will tend to "pump" mositure out of the headlight. I would drive it a couple of weeks to see if that effect works.

Porsche says they are allowed plus or minus 10% on the final engine dyno test just prior to installation. 300 HP rating can mean 270-330 HP. So..no.

Note that the 2010 and 2011 RX 350 were rated at 275 HP. The 2012 RX 350 is rated at 270 HP I much prefer to pay 10¢ less for each liter of gaz (in Montreal) than have an extra 5 HP On the other hand that extra 10 cents/liter may buy you more than 10 cents (15?) worth of additional gas mileage. Lexus didn't raise the bridge they lowerer the river. Simply enriched the mixture in order to run regular in a high compression engine without fear of detonation. If gas prices should go down substantially (fat chance) they'll go back to "Premium recommended".

Not sure about the 430 series but the earlier models were prone to failure of the "cushion" at the top of the front struts. Metal to metal sound going over a bump.

If the oil pressure light only comes on at idle or low RPM then the oil pressure is probably low at those times.

Use of regular will therefore adversely impact peak HP and FE. Hmmmm....seems like the definition of "de-tuned". It may not be PC to state it that way but retarding the timing will influence the areas you mentioned. If the 2012 RX has the same HP rating and FE, along with the same engine designation, then my opinion is that the salesperson is misinformed. But maybe tweaking the ECU could produce what is claimed with out degrading performance. Without a declaration from Lexus corporate it is all conjecture. The way it was explained to me by a factory engineer is that the timing is not changed, with sub-standard fuel the A/F mixture is enriched when the engine is under heavy load, WOT, etc, to prevent/alleviate detonation.

"de-tuned" seems a little harsh. The engine/transaxle control ECU firmware will automatically adjust the fuel mixture according to the need. Due to the compression ratio one could say that the engine is "tuned"/DESIGNED for premium, which it undoubtedly is, but will self-adapt when/if regular is used. Use of regular will therefore adversely impact peak HP and FE. Since the A/F ratio only need be "adjusted", enriched, with high cylinder fills, or if lugging the engine (a rarity with automatics), the decline in FE will be negligible

Assumption: The light only comes on at or near engine idle. At 230,000 miles it is entirely possible that you have so much "leakage" throughout the engine that the low pump volume at idle cannot keep the pressure up to "standard".

Have her try MAX heat after the engine warms up and report back.

You can ignore the VSC/Trac indication since that is simply a default with ANY CEL. But a dealer saying he can't read the code....WATCH OUT...!

There is a specialty wire brush "set" available that can be used to burnish the battery posts and battery connectors. Both positive and negative connectors should be removed, cleaned, and burnished on an annual basis. There is also some felt pads/rings that can be installed over each post, under the connectors, to delay the onset of the corrosion.

For about the last decade or more ALL EFI engines have been "tuned" for regular gas. Fuel a high compression engine that "requires(***)" premium fuel with regular and the ECU will automatic adjust, enrich, the A/F mixture under acceleration to abate even the slightest(***1) level of engine knock/ping. *** "requires" only for rated HP/Torque. ***1 New wideband non-resonant knock/ping sensors.

"..not long after getting a fill up..." CLUE. Top off with preminum. Knock sensor failure is unlikely, more likely engine actually knocking during acceleration.

I cannot imagine that they are made "soft" as Denso alternators that don't get oil on them ( just about every other Japanese car) go hundreds of thousands of kilometers without any service at all. And by the way, alternators use slip rings, not segmented commutators. Generators and starters use segments, but that's integral to their design. As I said earlier, if you had any real-world experience with these things, you'd know that. Just how did you get pass the "not the slip rings" and only see the "or commutator segments", later in the sentence..???

Once the system goes into cooling mode Denso makes use, exclusively, of the dehumidification capabilities of the A/C for windshield defogging. In certain climatic conditions, HUMID & COOL, that simply does not work. Or think of cabin HUMIDITY as the result of loading someone WET onboard, wet, sweaty snowskiier, etc.

"..leak on my LS wet the inside of the alternator with ATF.." "..Alternator, which had not failed..." "..the brushes "softened" somewhat,..." Slip ring brushes, ALL communtating brushes, are intentionally made "soft", compressed carbon/graphite powder, so that they wear out first, not the slip rings or commutator segments. Perfect example of the "urban legend", no way of actually knowing if the ATF fluid was, would be, a causative factor.

ALL Lexiis(***) have an issue of sudden windshield fogging, it's often simply the result of the way the A/C compressor is controlled. The best you can do is when the windshield fogs up, or hopefully as it begins to fog up, turn the temperature setpoint UP, to max if enough time, and then switch to defrost(defog) mode. The second way you can help yourself on this matter is to NEVER make use of the A/C (compressor) unless actual cabin cooling is needed. As of '01 there was a C-BEST option so that you could disable, indefinitely, the A/C compressor by simply switching off manually once. Later RXes, possibly yours, had another C-BEST options that prevented the system from switching automatically into "cooling", dash airflow, mode. In cooling mode there is no "warming" airflow to the windshield to keep the interior surface above dewpoint, the point at which windshield fogging onset begins. Keep your system in "heating" (footwell airflow) mode throughout the cool/cold period, and the A/C OFF and you will be much less likely to encounter a HAZARDOUS windshield fogging event. I try to remember to switch mine to "footwell/windshield" combined when it's raining. At one time there was an aftermarket DIY modification kit for early LS400 climate control ECUs that would automatically turn the heat demand up with defrost(defog) mode activation. I have never seen one for the Rx series. *** Any, industry wide, climate control system designed by Nippondenso, or Denso US.

The alternator failure on my 90 LS400 was a direct cause of the PS pump leaking. The alternator was drenched with PS fluid and both the alternator and the PS pump were replaced at the dealership after the tow truck got it there. This issue has been discussed on Lexus forums over and over since Lexus forums began. Based on your "opinion" you seem like a "newbie". Yes, I agree, the PS leak location is such that it drenches the alternator with fluid. And for quite a long time I accepted everyone's word, posts, that the alterator failures were the result of that drenching. But not after seeing the cause of 2 alternator failures due to DIY repair. "..replaced at the dealership.." So you have no direct evidence of the causative factor for the failure, if there was one. And in point of fact it appears that your alternator didn't fail, it was simply replaced due to having been drenched.

Well correlation in the face of large sample sizes makes a pretty compelling case. Fact; many LS400s with leaking PS pump also have alternator failures. Random mutually exclusive events? Or cause and effect. If it was only one or two complaints then maybe you can be dismissive. At some point thought the volume of the failures and the clear correlation is saying something even if you don't want to hear it. Anyway make your own opinion. I have a 2004 so don't have a dog in this race. As my kids say, whateva.... A) Fact; Many early model LS400's develop PS leaks. B) Fact; Early model LS400 alternators have "soft" slip rings. Direct Correlation...NONE.

".there are about 100.." And just how many of that 100 ever saw what had actually failed, or would even know, or remember, the difference when told. I would guess 98 out of 100 simply installed, or had installed, a new one and never opened the old one to see what had actually failed. Urban legend.

Yes, I know. But my personal experience with 3 LS400's was that the slip rings wore down to the bare metal shaft. ALL had PS leaks at one time or another and while I didn't disbelieve the common wisdom on the issue I am enough of a cheapskate and "if it ain't broke don't fix it" person that I didn't bother with the alternators until they actually failed. I suspect it all start as a dealer promoted "urban legend" like replacing the water pump with the timing belt. Speaking of timing belts, those same 3 LS400's are now over 200,000 miles without the timing belt being changed.

The power steering fluid leak is most definitely not the causative factor for alternator failures. The early, 92, etc, LS400 alternator slip rings used a very soft copper and that wears away within 100,000 miles or less, leaving the slip ring brushe(s) in contact with the bare metal alternator shaft. I replaced, fixed, the PS leak twice, after putting it off for too long, prior to the alternator failing as above.