Trying to track down a couple of air con issues in my LR3.

Not getting Cold air out at all, Put the IID tool on it. Shows 0 PSI.. Got a recharge kit and got some R134a in it and heard the Compressor kick in. Then the Pressure go back down to 0.

On the lines running down the passenger side above about the Rear Passenger door I saw Wet oily substances on the one line (Looks like this section goes to a Soft Heater Hose for a second. Not sure if this is stock or not.. so I trimmed back the Insulation and dont see anything.. dried it and havent been able to see it leaking again (even with trying to charge the system some what again)

With that. The rear (Behind the center console on the cieilng) climate controls do nothing. and no mid or rear vents work.


Couple things.

1 - Is there a connection point behind at the rear of the vehicle where the long lines from the front connect to go over the spare tire area and into the driver side Blower Compartment? If so where are these location / best way to check those For leaks.
2 - Are there any fuses or relays directly related to air conditioning or just the Blower / Fan Relays. Heat and Fans work fine. So not sure if there is a fuse or Relay to be checking for here or not.
3 - any other ideas besides taking it to a shop that can sniff out the leak and repair..

 

You need a gauge set not a GAP tool for proper PSI reading as you need to know the low and high side. In fact adding refrigerant can be incredibly dangerous without gauges because for all you know the pressure switch is defective and giving a false reading. Too much refrigerant will damage the compressor, rupture o-rings, etc. How much did you add? Did what you add contain oil also or just 134a? The rear HVAC module has both AC and a heater core. The heater core lines are a mix of hard aluminum pipe and soft rubber. These will go across the rear above the diff to the passenger side and up to the front with a few sections of rubber spliced in here and there. The AC lines will go straight forward to the front along the driver side and will be all aluminum with at couple of couplings that can leak. At the rear module close to the rear evap will be an expansion valve to control flow, as it gets cold it will close up reducing 134a flow.

In the engine bay just forward of the driver side firewall will be several all aluminum lines. Two "T" sections will split off with one set going to the firewall almost at center, this feeds the evap core at the dash. The ones that drop down go to the back

Your rear controls need to be set up front to allow control. If not then they will not work. Or you have a fuse, see manual.

Without proper gauge readings it is hard to say what the issue is, but more than likely you have a leak and the longer the compressor is ran with no refrigerant the higher the change it will be damaged. Refrigerant helps move oil around the system, without refrigerant the oil will get used or moved out of the compressor over time with no new oil brought into it. The compressor is always running at no less than 5%. When AC is demanded, the internal orifice will open and increase flow as directed by the HVAC controls.

 

Thanks so much for the detailed response. I appreciate it.

so you’re saying the lines that go do the passenger side before crossing over to the driver side rear quarter panel (where the rear system lives) are the heater lines. Not the ac lines?

I bought a standard refill kit from the store. With a gauge. When attached to the low port. No pressure. I could put about 1/4 of it in and get the gauge in the green. And see the pressure on the iid rising to match. once this gets above a certain threshold I can see the voltage to the ac compressor kick in on the iid tool.
after this (as well as before but faster once the compressor kicks in). The pressure on both physical and digital gauge start to decrease until it gets back to 0.

the center row over head contols. Do nothing as far as I can tell. I can active the mid vents in the ceiling from the front console. But not the center console knee level seats.

that’s less of my concern than having ac at all lol. Just wasn’t sure if related.

 

Yes.

The rear knee level vents are controlled by the front. The controls up on the roof for the rear only control the rear roof vents, C pillar vents and the one large vent (when on floor mode) right in front of the rear HVAC module. The controls will light up if the front HVAC setting allow then to be controlled independently. There is a button on the lower right of the from HVAC controls that shows the back of the truck with a couple of lines. It has two tiny LEDs indicators on the switch. "A" means automatic and the rear system will be in sync with the front, roof controls will not light up. The lower LED means the rear will be independent and controlled from the roof panel.

You added very, very little so I am surprised it tried to open the compressor orifice more. 1/4 can will not even come close to being enough to trip the high or low pressure values to cycle the compressor - which like I said, it always on anyway just at a reduced amount.

You need gauge readings with proper values. Your high side should be over 150 to 200psi with the low around 55psi when operating but values are very, very ambient air temperature dependent. You have a reference a chart. When off the two sides will equalize to the same PSI value. The difference between sides is critical to know.

 

thanks again. I’ll try to find someone with a set of gauges.

after that. Where’s the top places to look for a leak. As far as I can see I’m not seeing any oil / leaks to the naked eye nothing under the hood. Without removing the grill nothing at the condenser that I can see.
but in theory if I’m putting something in and seeing the gauge move up. Then depleat it’s going out somewhere

 

It can leak from anywhere. You have to check every connection, the entire condenser, etc. It can even be the compressor itself.

 

i love a goose chase.

Have you come across a diagram of all the lines and connections?

 

There are tons of diagrams online, just search with Google for LR3 Air conditioning lines using an image search. Also this has been covered on the forum many times over too. Lots of info out there..... The key is to look for the green-ish oil seeping out some place. If you find it at none of the joints then your most likely issue is compressor or condenser.

https://landroverforums.com/forum/lr...s-check-90255/

 

Also if you want to narrow down potential leaks and save headaches in the future, you can seal off the rear system for good. I myself may end up doing that, not sure yet since I use my rig for camping and I like having rear AC for the worst of the hot nights out. But it is an option.

 

Most cans of r134 meant to refill systems have a UV dye that shows up under a UV "black light" flaslight. It's the most precise and easiest way to find leaks.