Land Cruiser 2001 Model GXR, AC Low Suction Line Pressure

[sherqa]

What is r134a Freon Capacity of Land Cruiser 2001 Dual AC + Cool Box.

I replaced the expansion valve and filled 1200 grams of r134a Freon.
The Suction Line Pressure show 18 at 1000 rpm and 10 at 2000 rpm.
The ac is cooling at low rpm but less cooling at high rpm.

Do I need to add more Freon? I have checked on some websites some land cruiser Freon capacity is 1500 grams ?

[Cusser]

Isn't there a sticker under the hood that lists the R134a capacity ????

[JohnHere]

The specifications that I have for your 2001 Toyota Land Cruiser indicate the following: All engines, with rear A/C – 38 ounces net weight (1077 grams) of R-134a, and to check the under-hood decal for the amount of PAG-46 oil that it takes.

According to the specs, if you put in 1200 grams (42 ounces), then you overcharged it, which is part of the problem. You didn't mention whether you replaced the receiver/dryer, which should be done every time you open the system, and whether you evacuated it for at least one hour. Evacuation must be done as well before re-charging with pure R-134a (containing no sealers or other additives) to remove all the air and moisture that probably found its way inside.

[tbirdtbird]

We need both hi and lo side pressures in order to properly advise you. Hopefully you have a manifold gauge set with both lo and hi connections.
Testing should be done at 1500-1800 RPM , max fan, max cool, doors open (ie a full load test)

Why did you need to change out the expansion valve?

By what process did you introduce the freon charge?

Do not operate the AC until this problem is resolved. You low side pressure of 10 psi at 2K RPM will oil starve the compressor

[sherqa]

As the vehicle is 2nd Hand and the Model is also old 2001, I didn't find any sticker under the hood, but I searched on the net a found on some websites that dual ac with cool box the capacity is 1200 grams.
I didn't replaced the receiver / drier, the, I pull the vacuumed the system for 15 minutes and charges with R-134a 1200 grams.

[tbirdtbird]

Please re-read my last post, more info is needed.
Did you use the small cans to charge? Or a 30 lb jug and a scale? Did you purge your hoses on your manifold gauge set?
There were other questions, also

Vacuuming for 15 min is not sufficient, should be at least one hr, with an electric pump, not a pump that runs off compressed air

[JohnHere]

Is this a European-spec vehicle? If so, the refrigerant amount might be different than what I have for a similar U.S.-spec Land Cruiser.

To remove all the air and moisture that might have entered while you had the system open, a minimum evacuation time of one hour and preferably longer is recommended, as already mentioned.

After replacing the TXV and evacuating/re-charging the system, does it now perform well? What center vent temperatures are you seeing?

[sherqa]

Thanks to all for your value able answers,

Its Middle East the Temperature is between 40 to 45 C and the Humidity is 70-80%.

Last year the mechanic replaced the leak evaporator but didn’t change the expansion value and from that day the ac cooling was very poor, I asked several mechanics to replace the expansion valve but everyone said no need.

I started learning AC work from the Internet/YouTube and last month I opened the system and replaced the expansion valve myself, I used 2 small Cans and purged the air when changing the 2nd can, the cooling improved a bit, I thought the system is low on refrigerant.

Yesterday again I check the pressure the Static Pressure was 130, and with the AC ON at 1000 rpm the Low side shows 20 and high side 250, I charged 100 grams of more Freon, the cooling improved, at 1000 rpm the Low Side Pressure is 35 and the High Side is 360, the Ambient Temperate is 45C.
I guess some blockage at condenser as the high side pressure is high? what is the safe highest pressure for the High Side?

[JohnHere]

Yesterday again I check the pressure the Static Pressure was 130, and with the AC ON at 1000 rpm the Low side shows 20 and high side 250, I charged 100 grams of more Freon, the cooling improved, at 1000 rpm the Low Side Pressure is 35 and the High Side is 360, the Ambient Temperate is 45C.
I guess some blockage at condenser as the high side pressure is high?

1,000 RPM is slightly low for checking the pressures and vent temperatures. Bump up the engine speed to 1,500-1,800 RPM, A/C on "recirc," blower on high, doors and windows open, and see what you get. Make sure that the compressor is engaged, not cycled off, and that the fans are roaring.

It's possible that there is a blockage in the condenser. To your knowledge, has the compressor ever been replaced? If so, was the condenser replaced along with it?

If those components are original, the more likely cause of the high pressure on the high side is lack of airflow through the condenser. At an ambient temperature of 45°C (113°F), airflow through the condenser is crucial. Do the fans make a roaring sound when the compressor engages? If not, they're probably weak and in need of replacement, especially if they're the originals.

[sherqa]

All the components are original never changed except the evaporator and expansion valve.

I have checked again with the engine at 1800 rpm with the doors open and fan on high speed, I got the following :

Low Side Pressure : 25
High Side Pressure : 380
Vent Temperature : 23
at Ambient Temperate 40c and Humidity 60%

After Driving for 15 minutes with the Fan on High Speed at 2200 rpm the vent temperature dropped to 17c and when parked at 800rpm the vent temperature dropped to 15c, on low fan speed the vent temperature dropped to 8c.