LX450 AC urgent (1 Viewer)

[Ronald Rooij]

No, we did not measure the engine temp, but it is like as always on the dashboard. Radiator was tested, not spilling in the . Engine bay is hot, but that was always the case.
Nothing really changed. The first 3 very hot days the AC worked. After it was intermittent and stopped when the engine temp was at a certain level.

Been back at the AC shop. They are pretty knowledgeable. High pressure was high, 300psi. Replaced the drier, replaced expansion valve, cleaned condensor(s). Still high pressure. Tested with an extra fan gave some drop in pressure, putting the heatexchanger closer to the radiator gave also some reliëf.
When driving the driving wind will help.

What I noticed is that the radiator fan is maybe 2 inches smaller in diameter than the shroud. Is this normal? Might be that it has been replced with a smaller one, just lacking airflow.

 

[mudgudgeon]

but it is like as always on the dashboard

This means very little. If the gauge isn't in the red, it just means the car hasn't overheated yet.
If the gauge hits the red, too late. The engine is overheated.
For trouble shooting, the gauge on the dash is meaningless. Is coolant 20⁰ below AC thermal cut out? Or 1⁰ below?

In 40⁰ ambient temps, you're asking a lot of the engine cooling system.
Are you 20⁰ away from overheating the engine? Or 1⁰?

The engine fan needs to be 2" smaller than the shroud for clearance as the engine moves in relation to the body.

Poorly functioning fan clutch hub is a common fault with the cooling systems in these 30 year old cars

 

[jpoole]

Poorly functioning fan clutch hub is a common fault with the cooling systems in these 30 year old cars

If you see noticeably better cooling / AC performance when driving then I suspect your fan clutch has gotten wimpy. Tuning the fan clutch is cheap and easy and you can find plenty of info here on the forum about it.

I personally wouldn't drive an 80 in high ambient temps without the ability to check in on actual temps (not the stock, in dash gauge). If it's an odb2 truck get an odb2 bluetooth sender and the torque app and you are set. If it's odb1 you can get a cheap gauge that shows actual coolant temps or worst case an IR gun that will get you close.

 

[doc_random]

There is a cut off for the AC when the coolant temperature goes above 226'F / 108'C. The stock temperature gauge is not that helpful. Any temp between ~150 and ~230 does not move the gauge. The purpose of the AC cutoff is to protect the engine but it is at the expense of the cabin comfort. I am in Arizona USA where the highest temp we experienced was 50'C.
Getting some kind of OBD reader to show intake and coolant temperatures as mentioned is very helpful in understanding what is going on.
2nd this: "If it's an odb2 truck get an odb2 bluetooth sender and the torque app"

Conditions that make this worse, some of which have been mentioned above:
Driving slowly (low airflow)
Driving uphill (more demand on the engine)
Heavy vehicle with people and gear (more demand on the engine)
Driving in high gear (low engine RPM = lower airflow). You can manually downshift to get higher RPMs. A bit scary at first but it improves the airflow. *Do not red line the RPM.
Obstruction in front of the radiator (lights, winch?)
Radiator needs a flush. If Toyota red coolant and "other" green coolant were ever mixed you may have sludge creaking a blockage in the engine. I had this from the previous owner.
Fan clutch as mentioned above.
Add an electric auxiliary fan to the radiator with a thermal switch to kick in when things get hot.

This is a Bluetooth OBD2 reader (>5 years old , they should be faster and smaller by now) and the Torque app viewed on a Galaxy Tab E

 

[doc_random]

Ronald, I don't see your specific Land Cruiser model and aftermarket items shown. If you could share these details you may be able to get more specific suggestions from the forum.
Year, model, petrol/diesel, suspension lift, tire size, turbocharger/supercharger, bumpers, rock sliders, things on the roof, other aftermarket items, etc.

 

[Ronald Rooij]

Its a lx450, petrol 3" lift. 285x75R16 tires.
Winch, ledbar on front bumper.
Roofrack with 4 jerrycan and rooftoptent.
Rear subtank.

When we are in the next big town I will have the system flushed. I did replace all hoses but not those from the heater.

I have an obd2 reader at home not with me. Do not know if I can find one here in the middle of the Amazon.

 

[Ronald Rooij]

We have made it back to Suriname without major problems on the AC.

Problem was that we were leaking, very slowly, coolant from the bypass hoses. It was so little that it did not show as fluid or steam.
This caused the engine to heat intermittently above the tripping temp for AC-shut-off. Does not show on your dash.
Some responders on this thread were very right not to trust the dash-instruments.

We check fluids every other day or so, but when the AC-problems started we focussed mainly on the AC. Also because the fault analysis in the manual does not point you to check the coolant fluid in the first place. None of the garages we visited neither.

I had an OBD2 tool, but had put it in another car I was working on at home and forgot to put it back. Nowhere during the trip we were able to find another tool.
I now have it installed again and engine temperature stays constant.
AC cooling capacity is still marginal, but maybe that's the way it should be. Condensor is new, dryer is new, heat-exchanger is cleaned, compressor is ok and fluid-level is ok.

 

[jpoole]

AC cooling capacity is still marginal, but maybe that's the way it should be

My assumption is that something is still not right with the AC. After a full system refresh (new parts, recharge) the AC in my 80 blows cold at the vents. On hot days vents have to be setup correctly and the AC has to work to cool the entire interior but temps at the dash vents are consistently cold when the AC is running.

 

[alia176]

We have made it back to Suriname without major problems on the AC.

Problem was that we were leaking, very slowly, coolant from the bypass hoses. It was so little that it did not show as fluid or steam.
This caused the engine to heat intermittently above the tripping temp for AC-shut-off. Does not show on your dash.
Some responders on this thread were very right not to trust the dash-instruments.

We check fluids every other day or so, but when the AC-problems started we focussed mainly on the AC. Also because the fault analysis in the manual does not point you to check the coolant fluid in the first place. None of the garages we visited neither.

I had an OBD2 tool, but had put it in another car I was working on at home and forgot to put it back. Nowhere during the trip we were able to find another tool.
I now have it installed again and engine temperature stays constant.
AC cooling capacity is still marginal, but maybe that's the way it should be. Condensor is new, dryer is new, heat-exchanger is cleaned, compressor is ok and fluid-level is ok.

There are two other things that weren't replaced and it might be time to replace those. They are the a/c evaporator and the expansion valve and they live inside the dashboard. I did a FAQ on how to remove them, just look it up and you'll see lots of pics. Once you replace the last two remaining items, your a/c system should perform well in those temperatures.

Well, I forgot to mention the fan clutch. People in the hotter parts of USA tend to run the blue color fan clutch, and change out the fluid inside to a thicker fluid. I run 10,000 CST fluid but some folks run 20,000 CST fluid inside the fan clutches. You might to address the fan clutch so that it can pull more air through your radiator when it's really hot outside. I believe Landtank sells a modified blue fan clutch with the correct CST fluid inside.

Before you start working on the a/c, please record the temp of the air coming out of your vents. After doing the a/c work, record the same numbers again to see if you made a difference. It's always nice to have objective numbers before and after a project is completed.

Good luck amigo.

 

[Ronald Rooij]

There are two other things that weren't replaced and it might be time to replace those. They are the a/c evaporator and the expansion valve and they live inside the dashboard. I did a FAQ on how to remove them, just look it up and you'll see lots of pics. Once you replace the last two remaining items, your a/c system should perform well in those temperatures.

Well, I forgot to mention the fan clutch. People in the hotter parts of USA tend to run the blue color fan clutch, and change out the fluid inside to a thicker fluid. I run 10,000 CST fluid but some folks run 20,000 CST fluid inside the fan clutches. You might to address the fan clutch so that it can pull more air through your radiator when it's really hot outside. I believe Landtank sells a modified blue fan clutch with the correct CST fluid inside.

Before you start working on the a/c, please record the temp of the air coming out of your vents. After doing the a/c work, record the same numbers again to see if you made a difference. It's always nice to have objective numbers before and after a project is completed.

Good luck amigo.

Thanks for your reply. The evaporator was cleaned and in good condition, also the expansion valve was replaced. I will have an expert friend to check it later.
(when I've wheels under the car again).

I will check on the fan clutches, esp where to find them here.

Thanks

 

[alia176]

Thanks for your reply. The evaporator was cleaned and in good condition, also the expansion valve was replaced. I will have an expert friend to check it later.
(when I've wheels under the car again).

I will check on the fan clutches, esp where to find them here.

Thanks

You're absolutely sure the evaporator was cleaned and not the condenser?

 

[flintknapper]

You're absolutely sure the evaporator was cleaned and not the condenser?

Evaporator can be 'sort of' cleaned in place.....but definitely has to come out for the TXV to be replaced. So your question is a good one.

 

[mudgudgeon]

AC cooling capacity is still marginal, but maybe that's the way it should be. Condensor is new, dryer is new, heat-exchanger is cleaned, compressor is ok and fluid-level is ok.

AC in mine gives me frost bite on my ears, even in Australian summers.

 

[Ronald Rooij]

You're absolutely sure the evaporator was cleaned and not the condenser?

The condensor is new but not original Toyota (the heat-exchanger in front of the radiator). The evaporator (behind the glove box) was removed, externally cleaned and expasion valve replaced.
Could it be that the compressor does produce the right pressure, but not enough flow?

 

[LandLocked93]

What were the hi and lo side pressures again?
Anything less than 30 psi higher than ambient temp on high side and 30 psi lower than ambient temp on low side is cause for concern for refrigerant level.
Outside that it's an electrical/electronic issue.

 

[Ronald Rooij]

What were the hi and lo side pressures again?
Anything less than 30 psi higher than ambient temp on high side and 30 psi lower than ambient temp on low side is cause for concern for refrigerant level.
Outside that it's an electrical/electronic issue.

I will check next time when we have the car on wheels again. Probably after summer (car is in another country from where we live).