Just picked up immaculate '13 LX570 rear A/C not cold enough...intermittent driver footwell hiss (7 Viewers)
- Thread starter MrX
- Start date
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I’d vote for low coolant. You could pay a mechanic to test pressures and add refrigerant. That’s the first place I would start. I had multiple issues w my lx470. Finally found the leak, but I also got good at adding refrigerant on the side of the road.
1world1love
SILVER Star
FSM = Factory Service Manual and there should be a check down for this sort of thing but I am not sure. I am not sure about pulling codes for specific systems, but a simple code reader should provide any current codes that are being generated. If there is a faulty sensor then it should show up.
These trucks are not difficult to work on, but they are modern vehicles.
Luckily a lot of the Lexus/toyota systems have similar designs so I don't think you should be worried about Mr Cool for this. I'm sure he can sort it out.
Hissing noise from A/C expansion valve
forum.ih8mud.com
Here is a thread that potentially mentions same issue you are experiencing. I also had a similar experience with a hissing noise that was remedied with a proper A/C recharge as the system was just barely filled to the bottom end of spec. If the noise you are hearing goes away when you turn A/C off then I would posit it’s low on refrigerant.
So to follow up on this... I bought some refrigerant, added a tiny bit, and the rear started to get colder. I added some more, got colder, added some more and it got colder. Now dropping 30 degrees from ambient. I’m only at 68 in Nashville today but i I’ll follow up on a warmer day and see if my numbers hold. Just a data point for y’all
- Thread starter
- #26
Hissing noise from A/C expansion valve
Here is a thread that potentially mentions same issue you are experiencing. I also had a similar experience with a hissing noise that was remedied with a proper A/C recharge as the system was just barely filled to the bottom end of spec. If the noise you are hearing goes away when you turn A/C off then I would posit it’s low on refrigerant.
Thanks, I think so too.
Where do you insert the freon and is it easy? Thanks for the information! It's colder than that here in Knox today.
CharlieS
GOLD Star
Sounds like you have a leak. You might want to throw some gauges on it to make sure your pressures are safe. You don’t need to spend a ton on them - I have a cheap set from Harbor Fright or Northern Tool that have worked fine for years.
There’s a low side pressure nipple (probably not the right word) on the right side of the engine bay. It’s under a little plastic valve cap (like a tire) .... to be honest I just picked up a cheap ($40) bottle of Freon from Home Depot. If you YouTube adding Freon i bet there are plenty of videos
Good news. If it gets worse over time, you would have to check for leaks. Good luck.
bloc
SILVER Star
A few people have posted needing to add just a little refrigerant to get things working correctly.. and in most cases it held. Someone else posted that due to corrosion one of he rear AC lines had a super small pinhole leak.
OP I’d spend some time tracing the lines and looking for oily spots.
Either way glad you got it sorted and posted feedback to help others.
OP I’d spend some time tracing the lines and looking for oily spots.
Either way glad you got it sorted and posted feedback to help others.
- Thread starter
- #31
It's not sorted out yet but I have a ton of info on where to start thanks to these forums. I'm 80% sure it needs freon which my buddy can do for free. The hissing sound goes away when I turn all the A/C off.
@SharpeCat had a similar issue in an LX. He added Freon and it helped his situation. Not sure of the longevity of the fix.
When I experienced the rear being warmer it was a vast difference between the front and rear. To properly test for a leak is not easy/cheap, so I opted to top off the Freon and go from there.
The proper way to do it is to first drain your current refrigerant and then refill, but I just filled mine as I had no good way to drain it at home. I actually put quite a bit in, almost the full amount recommended if it started empty. There is a little glass/round window in one of your refrigerant lines (next to radiator fan when looking down at radiator from top), that lets you see your refrigerant flowing. A healthy supply will show a continuous stream of fluid without bubbles visible, a low amount will result in bubbles being visible as air flows besides the coolant. I filled until the stream was solid/no more bubbles.
I have not noticed my AC getting less cold since, so I assume that means if there is a leak, that it is nothing major. Summer is coming up again so I will put her through another round of tests and report back.
Pictures are to show the glass window for checking refrigerant flow. This is looking in from the front of the car and down in front of radiator on headlight driver side. Little dark circle next to the grey-knob (marked H) looking thing; you have to wipe off the dirt to see the fluid.
It’s called a sight glass. Make sure car is on and AC is on max when checking it. In addition to using the sight glass, I made sure the pressure was still in the green zone on the gauge/hose that came with the refrigerant refill kit as I was refilling it. The recommended amount can be found in your users manual, but I’ll see if I can dig it up.
For a 2010 it is 32.5 oz without cool box and about 2 more with cool box.
Example of visible bubbles/low refrigerant.
For a 2010 it is 32.5 oz without cool box and about 2 more with cool box.
Lexus Workshop Service and Repair Manuals > LX 570 V8-5.7L (3UR-FE) (2010) > Maintenance | Fluids | Refrigerant | Component Information | Specifications | Capacity Specifications
LX 570 V8-5.7L (3UR-FE) (2010) > Lexus Workshop Service and Repair Manuals > Maintenance | Fluids | Refrigerant | Component Information | Specifications | Capacity Specifications
workshop-manuals.com
Example of visible bubbles/low refrigerant.
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- Thread starter
- #35
Does anyone have a picture perhaps where this low pressure connection is? I still have all that engine cover crap on, but I’m pretty sure I found metal the line that connects to it. But isn’t said line supposed to be cold?
This is actually a repair that I can do. I know cars very well but I’m useless fixing things myself, unfortunately.
Thanks again. Lexus wanted $285, LOL. I’d still like to do this myself but Mr Cool down the street only charges $70.
This is actually a repair that I can do. I know cars very well but I’m useless fixing things myself, unfortunately.
Thanks again. Lexus wanted $285, LOL. I’d still like to do this myself but Mr Cool down the street only charges $70.
- Thread starter
- #37
Yes I was thinking that myself. I made an appointment. The refrigerant is $40 so what’s another $30 for pros to do it.
- Thread starter
- #38
It was just low on refrigerant. Added some and it's all ice cold. Probably a small, small leak somewhere that I don't care to fuss with. The PO of this truck never had any passengers (claims back seat was never even used) so the shoe sorta fits. Driver's side was always cold enough.
