1991LS400 Posted May 2, 2005 Share Posted May 2, 2005 Hey guys, Got a 1991 LS 400 and just noticed the past week or so that my A/C doesn't really blow cold air anymore. Even though the temperature for my A/C is on 65 degrees it feels like 75. It was just the driver side vents that were like that but now the whole A/C unit is like that. Anyone EXPERIENCED in 1st Gen LS 400's please help! Quote Link to comment Share on other sites More sharing options...
flanker271 Posted May 2, 2005 Share Posted May 2, 2005 The two side vents are supposed to blow a bit warmer than the center vents. I've had problem with my Freon leaking. Had the system charged 2 times in the time span of 1 year, but the Toyota dealer still could not find any leak. Yesterday it's blowing warm again, and the dealer told me my R12 is again completely gone, and as usual they could not find a leak!!! Quote Link to comment Share on other sites More sharing options...
1991LS400 Posted May 2, 2005 Author Share Posted May 2, 2005 The two side vents are supposed to blow a bit warmer than the center vents. I've had problem with my Freon leaking. Had the system charged 2 times in the time span of 1 year, but the Toyota dealer still could not find any leak. Yesterday it's blowing warm again, and the dealer told me my R12 is again completely gone, and as usual they could not find a leak!!! ← Well, it's not my two side vents that were blowing warm, it WAS the very left vent next to the driver door AND the left vent in the center vent console that were blowing warm. Now it's all of them. Where is the freon located? Can you actually see if there is a leak or not? Quote Link to comment Share on other sites More sharing options...
flanker271 Posted May 3, 2005 Share Posted May 3, 2005 The dealer added dye to my system last time they recharged it, but they could not find any dye coming out of my car. This is the weirdest thing ever. I'm paying $145.00 each time they recharge the freon so this issue has to be solved quick! Quote Link to comment Share on other sites More sharing options...
ylekiot1 Posted May 7, 2005 Share Posted May 7, 2005 I remember that there is a green cap connector to the AC freon line at the back (closer to the passenger side) of the engine compartment. That is the low side freon connector. There are procedures for charging the system in the shop manual. Maybe someone here has the directions posted on the website somewhere. I would, but I don't have a scanner and the books are boxed somewhere since the move. I just saw this and will add it to the post. This has a picture of where the connector is. http://www.saber.net/~monarch/acrecharge.jpg Quote Link to comment Share on other sites More sharing options...
POS Posted May 8, 2005 Share Posted May 8, 2005 91 - you may have a slow leak and that's why the air is blowing warmer. As I told another guy, you need a gauge set hooked up to it so you can see if the pressures suck. A common leak on these cars is the compressor shaft seal; mine leaked from there. You can rebuild the compressor (yuck) or redo the system. The problem with the older cars is that you can't just replace the compressor and call it a day - you need a new condensor ($500 @ Lexus), an expansion valve ($200 @ Lexus), a drier ($50 @ Napa), and a compressor ($6-700 at Lexus or Napa). AC jobs are gonna run $1500-1800 and it's real hard to pay that kind of money on a 15 year old car, but I did it anyway. Some guys on this forum (and others) have posted that you can simply change the compressor and call it a day - but I wonder how many of those guys repost when their AC fails again two months later. Quote Link to comment Share on other sites More sharing options...
Kennyr Posted May 8, 2005 Share Posted May 8, 2005 Hey guys,Got a 1991 LS 400 and just noticed the past week or so that my A/C doesn't really blow cold air anymore. Even though the temperature for my A/C is on 65 degrees it feels like 75. It was just the driver side vents that were like that but now the whole A/C unit is like that. Anyone EXPERIENCED in 1st Gen LS 400's please help! ← You have to find the leak. If there truly is dye in the system it should show up somewhere. If not, you may have a leaking evaporator in the car. For this you need some freon or R134 in the system. Then check the air coming out the vents with an electronic leak detector. I would get your system over to R134 first then inject dye, then find the leak with a Black light and an electronic leak detector. Good luck Quote Link to comment Share on other sites More sharing options...
1991LS400 Posted May 9, 2005 Author Share Posted May 9, 2005 Hey guys, Thanks for all the help! I understand about the leak that could be occuring in my A/C system, but I have one more thing to update this whole situation with...my A/C blows cold when the climate is cool outside. It's only when my car has been under the sun or it's really hot outside that it will blow hot air. Like I said, if it's a cool day my A/C will blow cold air. So how could that be a leak? Seems like something's not adding up. Please help, all this feedback is helping me. Quote Link to comment Share on other sites More sharing options...
flanker271 Posted May 9, 2005 Share Posted May 9, 2005 Thanks for all the help! I understand about the leak that could be occuring in my A/C system, but I have one more thing to update this whole situation with...my A/C blows cold when the climate is cool outside. It's only when my car has been under the sun or it's really hot outside that it will blow hot air. Like I said, if it's a cool day my A/C will blow cold air. So how could that be a leak? Seems like something's not adding up. Please help, all this feedback is helping me. This doesn't make sense. A/C shouldn't be temperature dependent. It'll take a while for the vents to blow cold air when outside temperature is hot. I assume that you waited long enough but it still blows warm. Are you sure the vents are indeed blowing cold a/c air instead of cool outside air when the temperature is low? Quote Link to comment Share on other sites More sharing options...
ylekiot1 Posted May 12, 2005 Share Posted May 12, 2005 You need freon. I had the same issue when I recharged mine a few days ago. After my last post on this my wife also stated that it ran only when it was cooler outside. My system Sunday had under 5 pounds of pressure in the system instead of 35-40 (70 degrees outside temp). After recharging the system it dawned on me that there might be a reson for that happening after seeing the chart on the freon bottle with the recharging instructions. It has a scale of pressure limits and ranges to recharge the system. With the warmer outside temperatures during recharge you have to get the ac system to a higher pressure to have it "completely charged" than when you have a lower outside temperature. Outside Low side Pressure Range Temp 65 25-35psi 70 35-40psi 75 35-45psi 80 40-50psi 85 45-55psi In a nutshell.. That means that the ac system pressure is lower during operation when it is cooler outside. The ac system will not turn on if there is not enough freon to protect the compressor. I am thinking that more freon is needed in the system to get it to run under higher pressures and temps. I'll bet you are at that fine line of freon left in your system to make your situation happen. I am 100 percent positive. Take a look at one of the bottles at the parts store that has a chart and you will see what I mean. I have recharged it twice now without any issues. In my opinion, a $12 can is better than a dealer guessing and spending $$$ to try and fix the issue. Nobody at this point can tell me where it is leaking so I am willing to take the risk of doing it myself every couple of months. If you decide to do it, just be sure to add freon and also PAG oil to keep the compressor lubricated. I dug up the manuals Sunday to do mine so if you need particulars, let me know. Quote Link to comment Share on other sites More sharing options...
Unclebob9 Posted September 22, 2006 Share Posted September 22, 2006 91 - you may have a slow leak and that's why the air is blowing warmer. As I told another guy, you need a gauge set hooked up to it so you can see if the pressures suck. A common leak on these cars is the compressor shaft seal; mine leaked from there. You can rebuild the compressor (yuck) or redo the system. The problem with the older cars is that you can't just replace the compressor and call it a day - you need a new condensor ($500 @ Lexus), an expansion valve ($200 @ Lexus), a drier ($50 @ Napa), and a compressor ($6-700 at Lexus or Napa). AC jobs are gonna run $1500-1800 and it's real hard to pay that kind of money on a 15 year old car, but I did it anyway. Some guys on this forum (and others) have posted that you can simply change the compressor and call it a day - but I wonder how many of those guys repost when their AC fails again two months later. My compressor went out on my 1990 LS400. I found a Company on Ebay that sells Bran new Lexus compressors for under $400. The dealer price was $1000 for a rebuilt and so were most local auto parts stores. I replaced only the compressor, that was 4 years ago and no problems. I also refilled the system with "Freeze 12" Rather than R12 freon. Freeze 12 is compatable with both R12 & R 134 without any major change overs. I bought a few cans of it and filled my system using the same hose I bought ye4ars ago at Grand Auto for $5. Is is now colder than it ever was back in the R12 days. You can also get it with Stop leak and oil in cans. If you have recharged your system more that once, you need compressor oil, because you have lost some through the leak as well. Freeze 12 is about $7 per can and it takes about 2 cans to fill the system. Best of luck: bob Quote Link to comment Share on other sites More sharing options...
AustinGT Posted September 23, 2006 Share Posted September 23, 2006 I have had the same problem with the two left vents blowing warmer air than the right two. I knew the compressor had a leak (I posted this problem about a month ago), but now I will get cold air randomly- when I drive to school in the morning, the system will only blow outside temp air. After sitting for two hours, it will blow nice cold air for about fifteen minutes then the left vents will start to warm up a little bit. Since it is starting to cool down in the Valley, it is not a huge deal (that is what the sunroof is for!), but it bugs me to have something not working properly . I have already put (after only 1.5 yrs- and the previous owner maintained it pretty well) almost $5,000 dollars into the car- I am not anxious to go out and spend another $1300 to have the compressor and evaporator replaced! Are these $400 compressors any good- because 400 sure sounds better than the 750 I was quoted (+labor!)? Quote Link to comment Share on other sites More sharing options...
wwest Posted September 23, 2006 Share Posted September 23, 2006 Hey guys, Thanks for all the help! I understand about the leak that could be occuring in my A/C system, but I have one more thing to update this whole situation with...my A/C blows cold when the climate is cool outside. It's only when my car has been under the sun or it's really hot outside that it will blow hot air. Like I said, if it's a cool day my A/C will blow cold air. So how could that be a leak? Seems like something's not adding up. Please help, all this feedback is helping me. The A/C compressor clutch will not engage if the refrigerant, freon, charge is too low, if the engine is at WOT, or: The engine water jacket temperature indicates that the engine is on the verge of overheating. Check and make sure the coolant level is topped off and the radiator cooling fans run at high speed when the engine temperature is up to normal operating temperature and the A/C compressor is operating, the A/C clutch is engaged. Quote Link to comment Share on other sites More sharing options...
GSsoldier Posted September 27, 2006 Share Posted September 27, 2006 Hey guys, Got a 1991 LS 400 and just noticed the past week or so that my A/C doesn't really blow cold air anymore. Even though the temperature for my A/C is on 65 degrees it feels like 75. It was just the driver side vents that were like that but now the whole A/C unit is like that. Anyone EXPERIENCED in 1st Gen LS 400's please help! hey i had the same problem with my car... i thought my blower was dying or something and everything (freeon compressor everything) was fine... try changing the air filters, since its gen 1 im almost sure that your airfilter is clogged, check it when i pulled mine out they were black as night... the original color was green haha... 14+ years will do that -joe Quote Link to comment Share on other sites More sharing options...
ModMan Posted September 27, 2006 Share Posted September 27, 2006 There is no filter on the Gen 1 LS400 HVAC system. Quote Link to comment Share on other sites More sharing options...
GSsoldier Posted September 29, 2006 Share Posted September 29, 2006 yea there is... if there isnt then i got charged for no reason... i saw the orginal. my father's friend is a lexus mechanic he did all of our work Quote Link to comment Share on other sites More sharing options...
ModMan Posted September 30, 2006 Share Posted September 30, 2006 I've replaced the evaporator core in my 92 LS400 and there wasn't any cabin air filter in sight. There isn't any cabin air filter listed in my LS 400 factory manual. Also, Newlexusparts.com doesn't list a filter for my LS400 but does list them for the 95-00 L S400 Quote Link to comment Share on other sites More sharing options...
LScott400 Posted September 30, 2006 Share Posted September 30, 2006 Our '93 and '94 both have them. How To Remove Cabin Air Filter, For 1993&94 LS400 Quote Link to comment Share on other sites More sharing options...
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