Cool Air

[KY350]

Beeing on the other side of the globe, its the middle of summer in Australia and it gets quite hot.

Whenever I leave the car in direct sunlight in 30+C (86+F) for about an hour, the inside temp is very high when I return to the car. I then manually set the temp to 22C (72F) with the fans speed on high. However, even after 10-15 minutes of driving, the cabin is still very warm inside and no where near 22C (but much cooler than the estimated 50C (122F) when I frist get in the car). I can feel cool air coming out from the dash vents, but funily enough, the temp of the air from the central passanger vent seems cooler to the feel than the air exiting from either the central drivers vent and the left and right side cabin vents.

I cannot understand why the air from 1 of the 4 vents would be cooler than the other 3 vents.

Also, with respect to the slow cool down rate of the interior temps, is that normal on a 91LS? Does tha air con system need a regass, or is regassing only done when there is no cool / hot air coming through the system?

[AzHotLS]

Now that I've fixed my AC (replaced compressor, dryer, evac/recharge with R12), I finally have cold air!! :D However, I'm experiencing the exact same symptoms KY350 mentions. :cries:

I did a search and came up with THESE threads, however, none of them gives a solution (or I missed it).

Mind you it is 110F here now, but the drivers side vent shouldn't be blowing warm air should it? If I close it, the center vents blow colder then when it is open. I'm using recirculate, not the fresh air setting.

Does anyone have a diagram of the AC/Heater duct layout behind the dash? Knowing duct/vent layout might help figure this out. I must have a leak somewhere in the ducts that is allowing warm air to be drawn in.

[SKperformance]

I would also check your filter for it being clogged and slowing the airflow.

Also low freon will cause the temp not to be as cold until the cars engine is run at a higher speed for an extended time to pressurize the system properly.

[AzHotLS]

Thanks SK.

Gen 1's don't have cabin filters, correct? Is there something else back there that I should be looking for?

I just had the AC system serviced yesterday, 2.5 lbs freon added with compressor/dryer. I'm hoping I don't have a leak that would cause it to be low on freon already. May have to explore that though. Maybe the compressor didn't need replacing after all.

No higher speed, just city driving. So if no leak, it should be blowing ice cold, yes?

I did post a thread last September where I complained of hot air coming from the vents on cool evenings. Maybe it's related. The hot water valve opens/closes so I don't think I'm getting heat per se.

How do you explain the temperature variations between vents? Driver's side and passenger's side vents "warm", left center vent cool, right center cold. Closing driver's side vent makes left center get cooler.

What's going on under/behind the dash?

[AzHotLS]

Okay SK, you called it. Low freon or no freon to be exact. High pressure hose from compressor to condenser has a leak at the metal to rubber crimp point. My worst fear has happened, it probably wasn't the compressor to begin with but the hose all along. $600 down the tubes (and into thin air) with $550 more to replace the hose. :cries: I'm taking it back to the shop Thursday (tomorrow) morning to replace the hose, evac/recharge, and 2.5 lbs more freon.

It would be just my luck, that after replacing the compressor and high pressure hose, that I'll find out that the evaporator has a leak too.

So we'll see what the air temps in the vents will be after the high pressure hose gets replaced.

[SKperformance]

Before they fill it they should be doing a nitrogen pressurization to make sure there are no leaks.

Also every Lexus has the space for a cabin filter just most early 90's models were not ordered with it in place.

[AzHotLS]

every Lexus has the space for a cabin filter just most early 90's models were not ordered with it in place

I'll look for it.

Update on the AC: After the compressor to condensor hose replacement the AC is blowing COLD now :D . No leaks after a week.

I bet the original compressor was good all along. Should I keep it just in case or see if someone wants to take it off my hands. If I get rid of it, how much do you think I could get for it?

I also no longer seem to have a charging issue. Just before the AC went out, the alternator didn't seem to charge the battery when it got hot. I replaced the battery. No problems while the AC was out. After the compressor was replaced and the freon leaked out after a day and a half, the battery needed to be charged. I was thinking I had an alternator problem, but now I'm thinking not as I haven't had a starting problem for a week now. What's the relationship to the compressor and alterntor in this situation?

[AzHotLS]

After a month I still have cold air. Yeah. :D

Still have charging problems though. Will get alternator replaced.

SK, I couldn't find the place where the cabin filter would go on my '90. I removed the passenger side lower footwell cover, nothing. I tried removing the glove box liner but can't figure it out. I removed the 5 tabs, but it doesn't seem to want to come out. Is there a trick, I don't want to break anything.

In lieu of a cabin filter, I did notice a metal screen behind each of the center vents. It sort of bubbles inwards toward the cabin. Is there a way to get to those and clean them? They are slightly blocked up. I just remembered this tutorial... Step 5 in this lexls tutorial shows how to remove the center vent grill to see them better. I could brush the screen but the dirt would still be behind it. Any thoughts?

[wwest]

One of the things that can help improve the efficiency of these early models is to disconnect the push/pull cable from the hot water flow control valve and lock-wire the valve completely SHUT during the summer months. And keep in mind that in recirculate mode with max cool set the lowest blower speed will not only be more efficient at cooling the interior down sooner it will also result in a much cooler level of airflow from the vents/outlets.