AC issues and Expansion Valve (1 Viewer)

[jayfrem]

Hi

I have 1999 LC 100 with 156 k miles on it.
1-2 years ago replaced evaporator due to constant leaks.
Than replaced Compressor . Bought it off Amazon ( Denso).

When in traffic AC is not very cold but works well when driving.

Looking to replace expansion valves ( never replaced) and clean lines.

Can anyone support where the exoansion valves are located ?

 

[nissanh]

Expansion valve is on the evaporator. You are probably low on freon, bad fan clutch, AC condenser and or radiator fins are clogged? You said the compressor is new (not reman), so it is out, otherwise it could be an issue as well in your case
There is a glass window located on the pressure sensor valve located below the trans cooler. When AC compressor is running you should not see any bubbles under the glass.

 

[bertnd]

agree with this- check your fan clutch before the expansion valve.

 

[jayfrem]

agree with this- check your fan clutch before the expansion valve.

Replaced the fluid in the fan clutch a year back.

Are expansion valves usually replaced ?

I also saw on the forum that when rear AC is less cool than front it may be expansion valve.

 

[bertnd]

they are a replaceable part yes, but my AC guy said they are less likely to fail than most other parts of the system. If the rear is less cool, then you should focus on the components in the rear (behind panel on opposite side of jack/subwoofer). O-rings can go bad easily too causing a leak- worth doing a dye test.
Also, even if fan clutch fluid was replaced, it may not be engaging as it should. If the symptoms are focused around when you don't have consistent high air flow over the condenser, then the fan is probably the problem. Have you watched to make sure it engages when it should an runs more than a few seconds?

 

[nissanh]

I am not a fan of filling the fan clutch. I went with an Aisin fan clutch, stay with oem or aisin clutch if you plan to replace it. Do you get good AC when rpms are high while stationary?

 

[jayfrem]

I am not a fan of filling the fan clutch. I went with an Aisin fan clutch, stay with oem or aisin clutch if you plan to replace it. Do you get good AC when rpms are high while stationary?

Yes i get good AC when RPM are high and it is that cold when in traffic.

Folks on MUD recommended to change the fluid in the fan clutch and use the thicker 10,000 viscocity . I was able only to find the 6,000 mm2

Btw is this equivalent to OEM Fan Clutch:


Aisin FCT-021 Engine Cooling Fan Clutch Amazon product ASIN B00829HCD4

 

[jayfrem]

Anyone knows the Aisin fan clutch for the LC 100 with OEM specs ?

 

[flintknapper]

Replaced the fluid in the fan clutch a year back.

Are expansion valves usually replaced ?

I also saw on the forum that when rear AC is less cool than front it may be expansion valve.

Very common for the rear air (vent temps) to be 6-8 degrees warmer than the front. Completely different environment back there (heat load).

 

[jayfrem]

Very common for the rear air (vent temps) to be 6-8 degrees warmer than the front. Completely different environment back there (heat load).

Yes the front is much cooler. You feel more of a fan in the rear.

Any input on location of rear expansion valve ? Already bought it and want to replace it.

 

[thought]

I just went through this issue on my 06 LX470. You might have it a bit better than me as the pre 03 trucks have an electric fan that helps cool the system when stopped.

My AC was shutting down when stopped in traffic when it was around 85 degrees ambient which seemed wrong to me. I replaced the fan clutch which did help a bit but what really helped the fix the issue was replacing the thermostat. I'm guessing my tstat wasn't opening up wide enough and that was allowing the engine temps to hit the 220 mark which is when the truck will shut down the ac.

After the tstat was changed out I spent around 1 hr in slow moving traffic on a 95 degree day with cold AC. My AC can still shut down when I idle it for too long a time but that's an edge case now vs happening anytime I parked the car in the sun and then got stuck in traffic.

 

[flintknapper]

Yes the front is much cooler. You feel more of a fan in the rear.

Any input on location of rear expansion valve ? Already bought it and want to replace it.

TXV (expansion valve) will be located on the Evaporator (both front and rear). Replacing it...involves evacuating the refrigerant from the system, pumping the system down and recharging. TXV's can (and do) fail but your issue sounds like it would be better addressed by increasing air flow through your condenser.

 

[jayfrem]

TXV (expansion valve) will be located on the Evaporator (both front and rear). Replacing it...involves evacuating the refrigerant from the system, pumping the system down and recharging. TXV's can (and do) fail but your issue sounds like it would be better addressed by increasing air flow through your condenser.

So i hd cooler AC when i replaced my fan clutch but rear AC is not cool.

In traffic coolness of AC is dropping. On Free higjways AC is great.

I am thinking:

- Power wash with low pressure radiator fins after taking radiator grill

- Should i replace the brand new Aisin clutch fluid with the fluid viwcocity 10,000 ?

- My 1999 has an electrical fan than upfront wondering if i can add another one ? If i hose the radiator with water and turn on AC it coola down pretty well.

Car tempwrature is normal and we have lots of uphills.

Any help appreciated.

 

[Pskhaat]

Anyone know where the signal is that turns on the front electric fan? I have never heard my 99's turn on even in the worst of heat traps.

 

[flintknapper]

Anyone know where the signal is that turns on the front electric fan? I have never heard my 99's turn on even in the worst of heat traps.

The condenser fan is activated by the Trinary switch (located just below your sight-glass in the high side line). IF operating correctly, it will complete the circuit to the fan (cause it to come on) at a specified pressure and drop out again...at a specified pressure.

If your fan never comes on...I would troubleshoot it by first applying 12volts directly to the fan itself to see if it is good and then work my way backwards through the wiring, connectors and relay.

 

[flintknapper]

Replaced the fluid in the fan clutch a year back.

Are expansion valves usually replaced ?

I also saw on the forum that when rear AC is less cool than front it may be expansion valve.

As concerns fan clutch fluid replacement, it depends largely upon where you live as to the CST rating you choose, but if Summertime temps (highs) are above 90°F I wouldn't go less than 15K-20K. Where I live (Deep East Texas) daytime temps (highs) from June through late September....will be low 90's to 105°F with very high humidity. I run 20K in my 80 and 100 series fan clutches, have Aux fans on both... and that is sufficient for my conditions.

Expansion valves can (and do) fail. They can do so in a number of ways (stick open, stick closed, stick partially open). Anytime an Evaporator is replaced...the TXV (relatively inexpensive) should be replaced also. But poor cooling is more often the result of other issues.

In response to the notion that the rear A/C should be as cool as the front A/C, this is patently false. The rear A/C is subject to more heat load than the front (solar gain, air exhange, etc). Expect vent temps back there to be 5-8°F warmer (on average) than the front.

 

[jayfrem]

As concerns fan clutch fluid replacement, it depends largely upon where you live as to the CST rating you choose, but if Summertime temps (highs) are above 90°F I wouldn't go less than 15K-20K. Where I live (Deep East Texas) daytime temps (highs) from June through late September....will be low 90's to 105°F with very high humidity. I run 20K in my 80 and 100 series fan clutches, have Aux fans on both... and that is sufficient for my conditions.

Expansion valves can (and do) fail. They can do so in a number of ways (stick open, stick closed, stick partially open). Anytime an Evaporator is replaced...the TXV (relatively inexpensive) should be replaced also. But poor cooling is more often the result of other issues.

In response to the notion that the rear A/C should be as cool as the front A/C, this is patently false. The rear A/C is subject to more heat load than the front (solar gain, air exhange, etc). Expect vent temps back there to be 5-8°F warmer (on average) than the front.

Yes where i live in Beirut summer are above 90 F.
Not sure i can find a 15 K or 20 K fluid. I have sourced a 10 K off Toyotapartsdiacount online store.

As far as an additional , is there enough space to fit one ? Which model to use )

On the LC 200 AC seems much cooler at these conditions. It probably has a better and more efficient cooling system.

Jay

 

[flintknapper]

Jayfrem wrote:

So i hd cooler AC when i replaced my fan clutch but rear AC is not cool.

Better airflow through the A/C condenser and radiator is always good. Many folks modify their fan clutch by replacing the silicone fluid with a heavier (CST) version for increased fan performance.

In traffic coolness of AC is dropping. On Free higjways AC is great.

Normal. You have less airflow (ram air) at lower speeds and obviously lower engine rpm (which drives the compressor). The A/C should always work better at highway speeds.

I am thinking:

- Power wash with low pressure radiator fins after taking radiator grill

It won't hurt to carefully clean both the radiator and condenser. Consider using a cleaner before pressure washing and be careful not bend the fins over. Don't spray at an angle.

- Should i replace the brand new Aisin clutch fluid with the fluid viwcocity 10,000 ?

I wouldn't open up a fan clutch for less than 15K. I run 20K in mine.

- My 1999 has an electrical fan than upfront wondering if i can add another one ?

A single fan should be enough if working properly in conjunction with your fan clutch.

If i hose the radiator with water and turn on AC it coola down pretty well.

To be expected. Heat can only flow from a hotter media/place to a cooler one. The cooler the release media is the faster this process can occur. Other considerations as well. But suffice to say...this is normal.

 

[flintknapper]

Yes where i live in Beirut summer are above 90 F.
Not sure i can find a 15 K or 20 K fluid. I have sourced a 10 K off Toyotapartsdiacount online store.

As far as an additional , is there enough space to fit one ? Which model to use )

On the LC 200 AC seems much cooler at these conditions. It probably has a better and more efficient cooling system.

Jay

Amazon product ASIN B004J1MTZA
Yes, LC 200 no doubt has an improved system.

 

[Pskhaat]

The condenser fan is activated by the Trinary switch (located just below your sight-glass in the high side line).

Excellent. Thank you!