yotoy82

Did you ever pinpoint the problem? I just bought a 1996 LS400 and when the car is off, specially on warmer summer days, every 2-5 minutes it makes sort of a farting/goose kinda sound, like Guzzz, then stops. I don't notice it as much in the winter. Sometimes in the summer even like a day later I can still hear the intermittent groaning sound. I have all the paperwork for the car, and apparently it made this same sound when it was brand new, and the first owner made complaints to lexus dealers 3 times and they couldn't pinpoint it or find the problem either. My dad has a 95 LS400 and it doesn't have this sound either. I mean there are no problems with the car, it drove 200,000 miles till now so obviously that goose sound isn't hurting anything, but its still awkward!

Good idea, I'll remember that next time! It's still taking forever to warm up though, but the heating comes out a bit faster. Will keep you posted on the mileage results.

Yah, I'll keep you posted, haven't had time to drive much or go to the gas station and fill up and see how it works. Thanks for the reminder on the battery disconnecting, I removed one terminal, not sure if it was the negative or the positive, does it matter which one? I removed one, the car was dead for 10 minutes, when I reconnected it and turned it on the clock was reset and trip meter etc. A weird thing I noticed is the FRONT DEFROST button light turned red and flashed intermittently for like 60 seconds, and the climate control thing was dead, super weird, never saw a read light on it before, but after a minute it self reset and then started working.

I dont have a check engine light on, will they still do a check?

Ya, except that I'm getting about 8 miles per gallon or about 120 miles per tank right now. Its been slowly getting worse each fill up, I have no idea why. Changed the sensor so can only hope that was the problem.

I had the tensioner, rings, pulleys, coolant, timing belt, water pump etc done at 95,000 miles on my dads 1995 LS400. Total price using all lexus/toyota parts with labor, (done at my favorite toyota dealership) came out to $750 tax and everything! There is literally no point in going to a Lexus dealer if you can find a good toyota dealer. Looking at around 350 in parts, possibly cheaper if you can find them yourselves somewhere, and the dealer charged me around 350 in labor. Just for your information, the car is 15 years old versus the 6 years change interval, never changed before, even though mileage it was time. And the belt was completely torn and shot, I'm pretty sure another year and it would have been a big headache!

ya, the fan connected to the drive belt of the engine, the cooling fan, its on all the time always

Well I doubt its the fans, they are all working properly. Changed the coolant sensor today, the old one was cracked/broken and corroded pretty bad!! Heres a picture, I hope this was the problem, will find out when I fill up and check the mileage again

Ok, well I noticed there are two fans. One on the outside of the radiator, it doesn't turn on when I start the cold car, but the one on the inside of the radiator starts up right away. That one is supposed to be running all the time or only when engine is warm?? Ok, I checked my dads working fine LS400 to compare. There are 2 fans , one on the outside, black, one on the inside, white. On my dads car even the white fan turns on right away so I guess thats normal

You know something, that actually crossed my mind, I just never checked it, doubt it is it but never know. You mean the fan in front of the radiator? It should not be on when I first turn on the car right?

Ya, the ECU Coolant temp sensor, hoping to get to it today, not the gauge sensor.

Ya I bought the OEM coolant sensor, just haven't gotten around to putting it in yet, seems like a lot of plastic covers to take off to get to it. Heres a picture of how high the needle gets after about 20 minutes. The rpm's seem kinda low when stopped and gear in drive, but when I put it in park it goes back up to 600, but the car is still perfectly smooth even at 400.

My dad has a 95 LS400, and it heats up in 10 minutes MAX and the needle goes to the halway point, they are essentially the same car which is why I'm guessing mine should too. Hot air comes out after bout 10 minutes, but doesn't really get that hot until the engine is as heated up as it will get. I used a New OEM Toyota/Lexus Thermostat and Gasket. I used OEM Toyota Red Coolant mixed 50/50 with distilled water. I don't remember off hand where the jiggle valve was, but read about it later on too, don't want to open it up again, but I do remember putting it exactly the way the original one was on. It takes about 15-20 minutes to warm up. When I say warm up, I mean to get to the optimal operating temperature. I know the temperature gauge inside the car isn't spot on but its pretty accurate, because when the car is cold you can hear the engine reving up more than normal and the rpms are high and when it FINALLY gets to the middle almost is when the rpm's slow down to 5-600 and the engine gets super quiet and smooth. Also, the heater is on auto and like the lexus does, it slowly raises the fan speed according to the engine temperature so only when the engine gets warm does the heater blow with full speed. Also, on my dads 95 LS400, heater blows full speed quite quick, also indicated a fast warming engine. If it gets fully warm, turn it off for 30-60 min, and start it up again, in 5 minutes tops its back to full operating temperature. My 96 LS400 well, after 30-60 minutes its pretty much back to cold again and waiting a lot longer to warm up. But ya, its only giving me 8 miles per gallon in the city now which is driving me crazy, all I can contemplate is that it has something to do with the engine not warming up. One thing is for sure, when the car gets warm, the heater blows out plenty of powerful heat. Will try checking the radiator hose like SRK says as well next time I go out. Appreciate the replies.

I have a 1996 LS400 I just bought with 204,000 Miles on it, all the paper work, properly maintained, beautiful condition actually. The only problem I noticed when I bought it in the summer was that the engine temperature needle never went to the exact middle like my fathers 1995 LS400. Mileage was alright, 23 highway average, not horrible, not great. And I drive VERY light footed. Then when winter came, I noticed the car took FOREVER to get warm. I changed the thermostat myself, the old one was the original, the center copper part was all scratched up, I assume from jamming up. It heats up only a BIT faster now but doesn't go all the way to the middle unless I get on the interstate and drive it hard, otherwise It still takes forever to warm up! I also changed the air filter. I drive mostly in the city, and the last two tanks, exclusively in the city, I get about 75 miles until the needle comes to the halfway point. To put it bluntly, highway and city driving mix, I'm getting 13 mpg, and just city driving I'm getting a whopping 8 mpg!!! Its been using 5w30 oil most of its life, but had 10w30 put in by accident when I got an oil change because forgot to mention it to the dealer, but I don't think this would make that much of a difference, although I intend to use 5w30 exclusively year round in it on the next oil change. It passed the emission testing just fine according to his paper work September 2008 at 182000 miles. No paperwork on oxygen sensors ever being changed though. No check engine lights on. It drives just fine, no funny sounds at all, smooth as butter. It is a bit rough while its cold and slow accelleration, but when it finallllly gets warm, it drives like a ROCKET. Paperwork shows lexus dealership in Naperville, Illinois changed the rotors, caps, wires and plugs at 144,000 miles Feb 2006, so I'm assuming they are platinum and have plenty of good life left in them! I ordered an OEM Coolant Sensor based on other threads, should be coming in soon and am hoping thats the problem. I also changed the FUEL FILTER and a PCV Valve . Can anyone else tell me if I'm missing something else that I should check, any help would be greatly appreciated (my wallet would appreciate it too!) The main concerns are why after a thermostat change does it still take forever to get warm, and why is the mileage HORRIBLE! And maybe the two are related to each other. I also tried "blurping the air" out of the coolant system, no effect. Please someone help!