jaswood

"AWD" Lexus RX in Michigan in the wintertime,...for your wife....??!! Is she HEAVILY insured...?? Buy the Lexus RX shop/repair manuals, or subscribe to techinfo.toyota.com, and read up on, fully comprehend, the theory of operation behind the RX's "AWD" system. From the '01 model thru the 2009 MY the RX was primarily a ONE-WHEEL DRIVE vehicle. Three simple, FULLY "OPEN", diff'ls. The only time the "AWD" system acts to apportion, re-apportion engine torque away from a tire, or tires, with marginal traction is POST, AFTER, traction has ALREADY been LOST. Wheelspin/slip HAS ALREADY BEGUN. Even with this series, those that included a VC, Viscous Clutch, '01 to the RX330 introduction, the VC fluid was reformulated so as to always remain "flaccid". By '01 Lexus had determined that the functionality of the VC along with the rear LSD for the '99 RX300 models where primary causative factors for the substantive level of premature driveline component failures owners of those early model years ('99 and less so for '00) were forced to endure. The Lexus sales and marketing material for those years, RX330/350 until 2010, still tout the use of the VC, a VC that actually DOES NOT EXIST. Again, check the shop/repair manual if you need confirmation of that. Take note that the newer RX and HL models (YOURS??) using this NON-FUNCTIONAL approach to "awd" have now added a TC "off" pushbutton in order to at least partially overcome the lack of even a semblance of "awd" functionality. The switch in 2010 to the new "AWD" system, introduced in the new Venza, will without question be a substantive improvement. But it remains to be seen as to whether Toyota has solved the driveline component failures arising from Ford's use of this same design in the Escape/Mariner/tribute series. Ford applied many, differing/various, fixes to this system over the 10 year period it was in use in order to abate the high driveline failure rate. Nothing seemed to work so Ford, apparently out of frustration, has now dropped the entire product line. A bit puzzling since that was to mean the reasonably successful hybrid series was also dropped. As a rule my wife doesn't drive our '01 "AWD" RX300 in the wintertime, most certainly not if it appears those roadbeds are forecast to become slippery. Not to belittle my wife's driving skills, she grew up in the true "toolies", Missouri Breaks area, of north-central MT and can be trusted even in the most severe wintertime conditions provided the vehicle in question is any RWD or rear biased AWD. Other than our daily drive to/from work even I would not be trustful of the RX for a distance, highway speeds, in wintertime conditions. But purchasing the "awd" '01 RX300 was my mistake. We had purchased an '00 AWD RX300 model that I had paid to have dyno'ed to confirm the touted 70/30 F/R torque split. It turned out that the "split" was there, but only after a brief period, 1-2 seconds or even less, of disparate F/R driveline rotation. Apparently it only took that small amount of time for the VC fluid to heat and and thereby increase the front to rear coupling coefficient. Unlike the FWD RX the '00 "AWD" model did not have TC so the needed disparate wheelspin/slip period was allowed. Shortly after purchasing the '01 model to get the HID and VSC/TC upgrade I discovered what I had lost in the trade, I no longer had an "AWD" vehicle in the same sense I had had in the '00. So my '01 quickly got 1.6" wheel spacers all around, an upgrade to 17X8 wheels and +1 tires. Wider tread, wider stance, and the ability to make use of tire chains on the rear initially should the need arise. It has. The RX does not have enough suspension clearance for the use of rear tire chains absent those spacers. When we purchased the initial RX, the '00, our '92 Jeep Cherokee limited with AWD/4WD/4X4 capability, was retired to a ranch in MT where it still does STELLAR wintertime duty. Sorry..inadvertent, wrong response, "insert" keystroke. Our '78 Targa stuck in McCall until a new Alternator could be shipped in and installed.

Lube the door hinges and the door lock. Look around the doors for a place of contact, somewhere that the paint is rubbed off due to continuous "vibratory" contact/rubbing. I don't see how the "soft" rubber door seals could be responsible for a creaking noise. Keep in mind that the RX400h chasis/body will shake and flex due to even minor roadbed pertubations and with the door tightly closed, FIRMLY closed, mounted tightly to the body front (hinges) and rear (door lock) something rubbing inside the door(s) might be the cause. Someone installed new door speakers...??

My '94 AWD Ford Aerostar will "chime" if the rear door isn't firmly closed and I drive over a bump, railroad tracks, etc. If your battery dies completely, or is removed without first installing a "keep-alive" battery, the engine/transmission ECU will get "mind-wiped" and will therefore fall back on the factory default control parameters. Your car now might "act" somewhat radically different for the next few days. It will take up to 200 miles, 4-6 drive cycles, for the ECU to re-learn the exacting control parameters for all the sensors and servos.

I understood, understand, FULLY, what engine "feathering" means.... But thanks for the clarification anyway.

"..feathering the gas pedal to provoke..." Broken honeycomb structure within a catalytic converter....? I have experienced the catalyst film coated honeycomb structure within the converter failing, crumbling apart in chunks. But that almost always at first resulted in those chunks blocking the exhaust flow intermittently, sometimes causing the engine power level to be reduced for acceleration. Idle exhaust flow pressure wouldn't rattle them about, and POWER level exhaust pressure would force them against the rear section of the converter..but engine feathered... More than maybe.

"..especially hot outside..." Possibly a VERY key statement. If the engine coolant begins to rise to, near, the point wherein a overheat condition would result, the A/C compressor will be disabled PRE-EMPTIVELY so as to prevent an actual overheat condition. Now, without the "burden" of pre-heated airflow from the A/C condensor reaching the radiator the coolant temperature will most likely decline back down the point wherein the A/C will again become operational. IMMHO the above condition most often results in failured or failing radiator eelctric cooling fans. Some do not operate at all unless the A/C active and/or the engine coolant is already approaching ~180F. Some with two fans will run them in series, only 6 volts each, unless/until the A/C is active or the coolant is tending toward overheating in which cases they are switch to parallel operation, a full 12 volts each. This latter case, both fans running, often fools auto mechanics/technicians into thinking all is well with the cooling fan operation when it is NOT. The 12 volt parallel operation is OFTEN required and if the fans do not properly switch into that mode to provide the extra necessary cooling the symptom you describe will result. "..leaving the refrigerant volume low..." Yes, EXACTLY, not enough LIQUID refrigerant available for full time coolling, only ~70% of the needed compressor cycling, the A/C condensing will not provide a HIGH heat load to the downstream radiator.... A bit counter-intuitive, but if you turn your temperature setpoint to MAXIMUM cooling and the use the blower speed to manually control the cabin comfort level this problem will abate. In maximum cooling mode the system's reheat/remix path will be closed to REHEAT thereby dramatically increasing the effectiveness, efficiency, of the A/C and the compressor cycling, the need to COOL the A/C condensor, might be reduced by a 10:1 factor. I have used this technique myself when one of the radiator cooling fans failed in my '01 911/996 C4 and the engine temperature began to climb into the RED. Mid-August, HOT day, dead-slow traffic on I40 around Little Rock Ar...

I have now tried different sound equalizer settings, FULL volume, and even a different speaker set, and I still cannot discern anything that I recognize as a "ticking" sound, only the obvious change in tire noise during differing pavment composition sections. But. I note that at time 0.25 you reach over and switch off the climate control system, inclusive of the A/C compressor clutch. Once you do that the previously stored liquid refrigerant will begin to bleed down since the metering into the evaporator does not close. I would be surprised if you could really discern the change in the noise level of the evaporator from that but I suppose anything is possible. There are also a couple of things that will/might happen automatically as a result of switching the system off. The climate control will evenually, maybe even right away, change, FORCE, the system's inlet airflow vane/door position from recirculate to FRESH. Be aware that in the previous "auto" mode unless you had specficially, manually, selected "FRESH" mode the inlet airflow might have been at any intermediate level, even in FULL recirculate mode. This, even with the "fresh" indicator brightly lighted. The second thing the system might/will do, automatically, is switch the system airflow into strictly, FULL, windshield airflow, OUTFLOW, mode. This latter function serves 2 purposes. With the system off the presumption is that you wish to minimize the level of airflow entering the cabin, more correctly stated the level if FRESH, possibly COLD airflow coming through the system due to forward motion of the vehicle. Forcing that incoming airflow to reverse flow direction will serve to reduce, "baffle", the volume of airflow. The second is quite possibly of substantually greater importance. Having the incoming outside airflow routed to the windshield will most certainly help to alleviate the possibility of interior windshield fogging. Having EITHER servomotor, the outside air inlet vane/door, or the windshield airflow routing, not be able to reach their respective "end-travel" fully open or closed as the case may be, will most definitely result in a series of "clicks", clicking, until the serrvomotor controlling ECU decides to give up. This servomotor end travel "clicking" issue can be asserted by disconnecting the battery and then listening to noise from the dash area as the battery is reconnected. The climate control system will go through a sequence to recalibrate, relearn, the end-travel points, fully off and fully closed, of all system vanes/doors.

The only significance in the sound I hear is the change in tire noise as you drive over differing highway pavement sections. IMMHO the primary "mount" area, early failure, would be the top mount/cushion for the front struts, the rear diff'l mounts/cushions, and/or the outter rear suspension mounts/cushions. The idle change is bothersome in that the engine ECU is programed to raise/keep the idle speed relatively constant with the on/off engagement, added load, of the compressor. It sound to me as if the compressor might be adding more load to the engine than the ECU is programmed to make up. "Slugging" the compressor, liquid refrigerant returning to the compressor inlet due to a to high a refrigerant charge might do that. That may also be the clicking sound, the compressor clutch kicking in and out as a result of the overcharge. The A/C indicator light should flash if the compressor, when the clutch is engaged, does not turn at a speed cognizant with engine RPM. I'm not sure what would happen if that was a temporary, intermittent, event.

Both... Even the slightest amount of dirt, fine dust, inside the distributor cap and then with a tad bit of moisture condensation overnight in addition and the engine will run rough until the moisture evaporates. Sometimes even worse, enough of the fine dust, metallic content dust, will get inside the distributor and you will see an actual arc path between one or 2 of the "connections" and the center power point. Mine had over 200k miles....

Sorry to say..but the fiberglas cloth and resin, 3M/NAPA, I tried would not adhere, long term, to the plastic surface of the reservior

The condition of the rubber door seals and the condition of the speaker in the driver's door are often tattle-tails.

http://us.lexusownersclub.com/forums/index.php?showtopic=72525

If you are considering a F/awd model then a 2010 MY RX would be highly desireable vs any previous MY ONE-WHEEL DRIVE "AWD" system. Plus you will need a complete, THOROUGH, understanding of the horribly FLAWED automatic climate control design.

As of the RX330 Lexus adopted the DBW, e-throttle system, to "protect the drive train". With the advent of the use of a more FE appropriate transaxle design with the original RX MY Lexus found that the transaxle gear change timing did not always match up with the driver's need, desire, for quick acceleration. DBW adoption allowed the engineers to prevent the throttle from responding to accelerator depression unless/until the currently commanded gear change was fully complete. That effect may be what you are encountering orif it is most noticeable during coastdown periods it might even be the full fuel cut technique effects that you "feel".

Forward motion of the vehicle will always slightly pressurize the atmosphere near the bottom of the windshield thereby FORCING airflow through the HVAC system. Since you DO NOT wish to have the system in recirc mode(***) during cool/cold weather operation the best you can do is set the temperature to MAX heating, select the defrost/defog/demist mode, and then switch the system completely off. Reversing the direction of the incoming airflow in this manner will tend to "baffle" the level of incoming airflow volume while also directing it away from your face/body/feet. It will also serve, at the same time, to keep the interior surface of the windshield warmed to well about the dewpoint of the cabin atmosphere. If the resulting airflow "reflected" off the windshield becomes to warm for comfort the temperature can be easily lowered as is obvious. *** some systems will not remain in reciculate mode even with the system off, many will even automatically switch to fresh as you turn off the system, some will even also automatically direct the incoming airflow to the windshield routing with the system switched off. If you check the condition, STATE, of the airflow routing upon startup on a cold morning prior to the coolant being warm enough for the heater blower to start, odds are, 100:1, you will discover it to be parked in the windshield airflow mode.

Heating wise you are encountering an anomally, I would say design FLAW, of the Lexus cliamte control design. More correctly a design flaw of the system designed and produced by NipponDenso for the majority of asian manufactured vehicles, and by Denso US fro a goodly portion of US manufacturers. The base "fly in the ointment" is that in cool or cold climates and in fully automatic mode as the cabin temperature rises to, or closely nearby, your temperature setpoint the system will automatically switch into "cooling" mode, system airflow outlet at the dash level. That airflow, by design, will now be as much as 20F cooler that what was previously the temperature level from the footwell, floor outlets. If the OAT, or cabin inlet (recirculate mode) airflow entering the system is warm enough, above ~45F for OAT (recirc inlet will certainly be), then a substantual level of dehumidification will result. So now you have not only "cool" airflow directed to your face and upper body, that "cool" airflow is also quite DRY. Net effect for the Human Comfort Equation, you "feel" chilled. Yet another adverse effect is that if left to itsself, left in this "cooling" mode, there is NO warming airflow to the interior surface of the windshield in order to keep its surface temperature well above dewpoint. DANGEROUS that...! Why...?? Idiot NipponDenso engineers would be my best guess. But help is on the way. The first thing you should do, at least initially, is to ALWAYS manually switch the system to footwell/floor, or BACK into this mode once it switches to dash outlet mode at a time when HEATING is desireable. As of '01 there was 2 C-BEST options added. 1.) You can have the dealer set these so the A/C can be disabled indefinitely, throughout multiple ignition power on/off cycles. 2.) The dealer can set a 2nd option such that the A/C will be unlinked from operating automatically (with no indication to the driver) in defrost/defog/demist modes. This will prevent the COOLING of the system airflow when the human comfort equation dictates HEAT as a requirement. Later models, ceratinly beyond my '01, have an additional C-BEST option wherein the system can be prevented for automatically switching into "dash"/COOLING, airflow mode. Another aspect, corrective aspect, FIX, later added to these systems is the ability (REQUIREMENT) to automatically switch into fresh inlet airflow mode AND automatically switch in windshield/floor "HEATING" mode once the is already, or OAT declines, below about 34F. Since otherwise, absent your intervention as above or the application of these newer "FIXES", these systems will steadfastly remain in "cooling" mode. ABSOLUTELY NO warming airflow to the interior surface of the windshield and thereby becoming subject to the HAZARDS of sudden unexpected fogging, DENSE fogging of the windshield interior surface. For more info see: http://us.lexusownersclub.com/forums/index.php?showtopic=72410

Possible, but IMMHO far from reasonable, to much work for little gain.

My LS had only 5k miles when I upgraded to 16" rims.... Tire swap may have been done to acquire QUIETNESS. Also, with 1 tire punctured beyond repair and the other 3 well worn dealers would recommend replacing all 4.

Ebay or Craigslist..mine, $15, came from the latter.

Tach bouncing symptom ruled out cat issue for me.

To help isolate the problem area disable the VSC/Trac system. With the engine idling disconnect the MAF/IAT sensor. The engine will die, reconnect the MAF/IAT sensor and then restart the engine. For the next few drive cycles you will now have a CEL for which no harm will come and the VSC/trac system will be disabled until the CEL clears of itsself. The MAF/IAT sensor module is a 2" square black plastic module in the air intake duct just downstream from the engihe sir intake filter.

You don't.

Replace or CLEAN the distributor caps and rotors.

It sounds as if you encountered a situation wherein the TC activated for an extended period, mine will do that is I drive through a long muddy area on an otherwise dirt road. An extended period of TC activation is considered abnormal so you get a diagnostic indication that clears itself within a few miles. "shaking" was probably the TC braking effect, "ABS-like" effect. The engine should not stop but it will be FULLY dethrottled, no response to the gas pedal during TC (or VSC) activation.