rtd111

This is similar to my problem with the SC400 (I just posted a no-reply post). It was suggested previously that the heater control valve may be the problem. In my case, there is no heat inside, coolant starts escaping (when hot / when under pressure, looks like from around the radiator or reservoir cap) and then the heater gauge climbs to red. Thermostat tested good. I can't imagine that the heater control valve would be the cause: because even without any heat, the system should work. So I've been looking for something else. Could it be as simple as the reservoir cap?

Its been quiet... any thoughts? Thanks in advance.

Any thoughts or suggestions, folks? Given there is a problem with coolant leak only when running (escaping when hot and under pressure), and its not the thermostat, perhaps there are a several more directed questions here for various suspects: - How do I test there is no leak in the radiator? - How to test the heater core and the sensor there to make sure coolant path is not "clogged" - how to check for air in the system - how to check the water pump Looks like something is causing very high pressure in the system and the coolant is being forced from the weakest points (???) Thanks.

I am in the middle of a similar problem: temp gauge goes red, no heat, loss of coolant (escaping from around the radiator I believe). However, its on my 94 SC400. If you care to read it (THANKS), ref: http://us.lexusownersclub.com/forums/index...mp;#entry337775 Problem remains unsolved. Note that I had not had TB/WP changed -- this problem started one fine day. I have search both LS400 and SC400 forums -- this thread seems to be most promising. QU: How do you remove the air in the coolant system? Request: if you read my posting on SC400 forum, any ideas / suggestions?

Coming back online after a few months: the SC400 with the problem I stated has been sitting idle for the last 4 months. I had my brother's car but that is going away so I need to fix this problem in the next 3-4 weeks. Answering a prev qu: the timing belt and water pump were replace about 6-7 years ago, at 75K miles. I bought the car used at the time and it had the 90K service done by the Lexus dealer. I have all the records. Also, I tested the thermostat yday: the valve opens around the 80-90 degree-C temp. Per the quote above, what tube is this? Can you point to it in the manual or send a pic? In reading similar threads on the LS400 forum, one diagnostic is an air pocket in the system. I had drained and refilled coolant about 2 years ago now (Dec 06) and this problem started about 14 months into that (Mar-Apr 08). So could the air pocket theory apply? Note that its been about 6-7 months since this problem first surfaced. So, any new learnings in this group that might help? Thanks in advance.

Sorry, I have been out the past few weeks & too much work. No there is no white smoke from the tail pipe. Here's the status. After I filled the coolant around end of May, I've not had to fill it further. There may be a slow leak - on occasion, when I open the hood, I see a small puddle on the undercarriage. Actually, now that you mention it, the a/c has become weak though it does blow a bit of cold air. The hot air still comes on at about 76 deg (I would expect it at 71 - Seattle weather was rainy / cold couple of weeks back). Basically, the problem remains unresolved, and it seems to be on a "slow burn". I will post pics in the next posting -- car's not here right now. Thanx for all your responses. Expect to be more regular with replies.

Thanx for the response. How can I confirm this? Its either the heater solenoid or what you are suggesting. I could make the smaller investment (in the solenoid) and see if it fixes it, or move on to the TB & WP... or Where do look for the leak -- I don't see any obvious drip with the engine running, hot or cold. I noticed after my 15 miles drive home today that there was just a very small puddle in the undercarriage cover -- right under the reservoir actually. Note that the heat works now since I topped off the coolant. But it blows hot only when I dial up to max or close to that -- at 71-72 degree setting, I got cooler, not cold air (note that I am in Seattle and did need to use the heat this morning). Appreciate additional insights.

I had better luck searching the LS400 forum on coolant leaks. I have an SC400. My issue is posted here: http://us.lexusownersclub.com/forums/index...showtopic=48224 I also own a 91 LS400 and these two cars have a lot in common -- the heating / cooling system is largely the same. In some of the articles I found here, there's suggestions this problem may be due to water pump failing. The WP was replaced with the timing belt at 75K miles. Car currently has 124K. Could that go out this fast? Any help appreciated.

94 SC400 124K miles I had noticed an odd smell in the car, in retrospect, it was leaking coolant, I believe. A few days later, I noticed the temp needle went to 3/4 + level -- usually its barely at half. The same morning I noticed the car was not blowing cold air even when I dialed up the temperature (it was cold outside). My wife said she saw a trail of something out of the car (was coolant). I pop the hood. There was remnants of dried coolant all over -- some even splashed towards the engine cover and thermostat area (the area was dry there but had white spots, of evaporating coolant). The coolant reservoir was empty. I've refilled it to see obvious leaks. There aren't any. Poking around, I discovered the coolant pipe near the firewall is the culprit: it's got dried / caked coolant on it. There's some sort of a temp/ac sensor there I believe with intake-outtake pipes. I unclamped the one running along the firewall - it is dry. the one running below is caked and this goes into the interior vents, I deduce (blowing hot or cold air depending on A/c off or on). Qu: 1) any suggestions on how to diagnose the problem 2) the lower vent pipe has an oddball clamp on it. With the caking around it, its hard to figure out how to remove it. Looks like a pin that I could just pull down to unclamp. Is this right? I will clean up the caking there and try again -- though its hard to reach there. I've removed the two screws that hold the "sensor". 3) Should there have been coolant in the horizontal pipe: the one that goes to the sensor? Also what's the circulation path for the coolant here? I recall in a coolant flush tutorial that this pipe is another way to empty the coolant. Does the car need to be running to have coolant in this pipe? Thanks for your responses.

It is your struts bro I hace the same problem. If the noise dosent bother you just live with it. Sometimes SEARS has free instilation but if not it shouldnt cost more than 450 total for all 4 good luck Is there any DIY links to do this job? I understand the need for special tools, etc. Just want to know, outside of that, how hard this job is. I get the noise only from the front: does that mean I need to do just the front 2? Thx in advance.

SC400, 1994, 120K miles This has been happening for a few months now: - on a cold start, like when starting first thing in the morning (irresp of summer or winter), I need to crank it twice, sometime three times before the car start. Very consistent. (Haven't got the battery checked but should this weekend or next for cranking amps) - However, the more bizarre thing is that, over the past month or two, the clock changes time during starts (irrespective of one crank or two or more). This is very intermittent -- maybe happens once every 2-3 days. The clock always resets to 1:00. I am not sure, but I think it happened once when I was driving the car too (but perhaps this has got to my head -- since I don't bother to set the time anymore, I might be wrong there). Anyways, that's the data. Any thoughts? Thanx in advance.

I got the part, it was as expected, and Mr P_S included a little extra something to compensate for the early confusion / lack of communication. Alls well that ends well. Thanx.

OK Appreciate the reply. I wish you could have just sent a quick note. I will wait for the antenna. Thanx for your diligence.

OK, Mr Phamily Ensang: You need to deliver on the part I bought from you. I am putting this out there because since Jun 14, you have gone silent on me: you have failed to reply to my messages and failed to provide status of whether you've shipped the part or issued a refund. Let it be known to everyone that this gentleman has not delivered since I paid him 14 days ago.

Hey, any of the parts I've requested available? Also, radio antenna: entire unit, including the blue box -- see pics #8 or #9 on lexls. Thanx.

Lenore, when you say you did yourself, did you do the work or a mechanic / dealer? I just got my 91 LS400 converted by a mechanic. However, the compressor would not run and/or the clutch would not engage. He said the problem is with the cable from relay to clutch but evenso, the compressor and clutch likely needs replacing. The system was emptied of R134 given the a/c would not work. Anyone have any thoughts on this? Searching this forum, I found Tech Choice Parts on Ebay and many others there too. Anyone have any - experience with any Ebay compressors+clutch units and - have you installed one yourself (I would go back to the mechanic to refill / test). Any suggestions or ideas? Thanx in advance.

Looking for (in order of priority) 1) Intake Air Chamber (or Air Intake Duct) that connects between the filter and the Throttle body. 2) Temp Settings LCD 3) Hood struts 4) Solenoid on the steering rack Please PM if available.

91 LS400, 155K miles. Any ideas how to test or adjust the TRAC sensor referred to in the above post? I cleaned out my throttle body today. The plan actually was to replace the TPS (one closer to the engine), because of TRAC light and code 41. But while I was at it, I decided to clean the TB. Used a whole can of the cleaner stuff. Quite a mess. Anyways, the TB is nice and shiny now. Began to put the new TPS (part #89452-22090 per LexLs Tutorial). If I adjust the TPS per the tutorial, the engine revs at over 3K. Tried several times and RPMs would jump around between 1.8K to over 3K. I wasn't sure if this was due to mis-setting of the TPS or the TRAC sensor. So I put my old TPS (part #89452-12050) back in. And I put both sensors in WITHOUT engaging the "metal prongs" that control the valve, and that got the RPM down to a more reasonable 750. I drove the car around a bit and it drives as it always did (maybe a little easier because of the clean TB :P ). Any ideas on how to adjust these two sensors? I can retry the TPS using the lexls tutorial but need assistance on the TRAC. BTW, the TRAC light remains on now right from when I start the the engine. Previously, it would come on after driving a few miles. Haven't rechecked the code lately. Thanks in advance.

I called the local Lexus dealer. Here's the scoop. To have the convenience of the remote key, I'd have to order "a chip" and one (or more) remote key(s) programmed for that chip. The cost is $425. He looked up the record on the car and said he is not sure of the "computer" is bad as well. He can find out only after getting the chip and the matching key. I did not ask him the implication if the computer was bad. Question: has anyone done this before? Or any other sources for the "chip and key" combo? I also could get a regular key, ala sparekeys.com, and that would be $75 for one. Many thanx.

Well, here it is. In any case, these procedures did not work for me. (The battery in the key reads 2.94V) In the link above, step 8 fails: when I remove the key, the locks do not cycle. Maybe I am imagining it, but its gotten difficult to insert this key in the ignition since I tried this (about 10 times). My earlier fear that the problem with the key not working on the driver-side door creeping to the ignition :(! During reprogramming, I had to abort a couple of times because the key would not sink all the way in. Even when it did, I had to wiggle, remove, rotate 180deg & reinsert, wiggle, and maybe it would sink. Its getting a little edgy. I am going to stash this key away. Because the other key, which does not have the keyless entry remote, works quite smoothly on the driver's side door as well as the ignition. I dont have to wiggle it or anything to make it work. Its the one I will begin using here on out. Its subtle but I think the "teeth" on the two keys don't quite match. Any other ideas or suggestions. Perhaps I should call Lexus and get the one time lifetime replacement of the ECU and get new keys reprogrammed? Grazie.

Thanx for the instructions. I have not tried this yet -- can't wait to go out and do this, hopefully in the next 20 mins. There is a question however: 9. Press and release LOCK and UNLOCK buttons together. Which LOCK and UNLOCK buttons. On the door, its a toggle. On my key, its the old style with a single button on the side of the key. Its not a dongle with lock, unlock, alarm,... buttons. And 7. Switch the ignition ON and OFF once to program a key remote transmitter code, while retaining the original codes. Who's retaining the orig codes: key or the car ("System"? Appreciate it.

91 LS400, 155K miles Q: How can I diagnose problem with my keyless remote? It fails to lock-unlock the doors or arm/disarm the alarm. Details... I got this car used from a dealer almost 10 years ago. From day one the remote on the key could not arm/disarm the security or lock/unlock the doors. As "discussed" during the purchase, I did take the car in to have this issue looked at. In fact, had to take it several times, and in the end the svc dept said they will not be able to make it work and I would have to just have to live with it. I know I got taken on this one. Why am I bringing this up now? Well, I happened to read a post on this forum about reprogramming keys and ECU (though it seems the codes are in a transponder chip not related to the ECU, if that's true of 1st gen LS400s as well). I now would like to consider all options to make this work. Its likely that something component (transponder, ECU, ???) was switched out in this car that's caused the keyless lock/unlock to fail. Not having the remote work has always been a pain. Furthermore, over the past several months, the key will not insert into the driver side door lock and is barely working on the passenger side door. (Yes, I have tried WD40 and some others, though not a graphite lubricant yet). At some pt, I will need to fix the pins and springs or whatever it is that's messed it with the mechanism up but I fear I wont be able to unlock the car one day. The spare key (without the keyless remote) works a little better/smoother on the passenger side door, and occasionally (1 in 5 times) will even unlock the driver side door. BTW, no problem with the ignition and starting, etc with either key. Thoughts? Thanx in advance for your responses.

Isn't there some side effects to using Seaform/Berryman's or a follow up action? Like the gunk / carbon that it loosens, where does it go? Does it get trapped in a filter / exhaust-system that needs cleaning. I recall reading a lengthy article on this forum about pro-cons once (but could not locate it when I just searched for it -- I get an error, likely operator error.)

91 LS400. I am interested in getting the filter that is in the solenoid on the steering rack. I can get one only with a remanf rack, which is overkill. If you have a bad solenoid or just the filter -- even if the gauze is ripped or torn, I can take it off your hands... for a reasonable price and shipping costs. Or any other suggestions how to acquire this part?

1991 LS400. Had a small parking accident that broke the plastic cover of the passenger side headlamp -- the one in the corner. Bulb is still good and the light works just fine. It had popped out a bit but I was able to rescrew it in place. I tried looking for a non-working unit at a salvage place so I could just use the plastic cover but no luck. Plus its unclear that I'll be able to seal this correctly (if I cannot put my bulb and use the salvaged unit as is). Any pointers? Checking around, I see some complete units ... aftermarket stuff. I am afraid this might cause mismatch or I could get two aftermarket units. Anyone have any leads or experience with this product from any parts vendor or from Ebay? Haven't checked with dealer yet but thought I would try this channel for pointers first. Mucho gracias.