Ac Fyi (1 Viewer)

[94landcruiser]

I decided to use the Sea Foam I have had since I got back in February and at 1/4 tank put a can in and did the PCV Suck.

After the initial 1/2 can inhale and subsequent engine stall I let it sit for 30 minutes, than sucked the rest of the can.

I had positioned my truck at the back of the garage, tail pipe out the patio door (can you tell I waited until my Wife was gone?)

I turned it on and revved a huge cloud out the tail pipe and let it idle and went inside for breakfast after about ten minutes I came back and the smoke was gone but I realised I had left the AC on also and it was now blowing hot. DAMN!

I checked the entire system, agonized, searched the forum for ideas, looked at the FSM, kicked myself for breaking it and generally allowed my day to be ruined.

I just went to the store, after it sat for several hours and it works!

Does the system have some kind of a safety that shuts down if it senses possible harm being done to it?

Man am I glad. I have a 1400 mile Laredo trip coming up and have done it once sans AC in my BMW and can say without fear of contradiction it sucks driving in the heat long distances without AC!

 

[cruiserdan]

The compressor cuts out when the engine coolant temp reaches 226 degrees F. It could be you got it hot.

 

[94landcruiser]

Good to know, needle was where it lives, at the 1/4 mark or about 175 (per this guide)

Full sweep peg to peg is 94°

Pegged hot 244°
Top of red is 227°
Bottom of red 217°
Center is approximately 189°
Cold line is 160°
Pegged cold 150°

Thanks again to RavenTai for his mod.

 

[94landcruiser]

Well this just recurred. I was waiting for under five minutes for my Wife to come out of a store with the engine idling and the ac on. The temp gauge did not move and the air got warmer like the compressor had stopped cycling.

I have not checked to see if it is working but figure it must be whatever protection circuit the compressor has. Where do I look for this circuit? Can I replace or repair it or will I need a new compressor?

Thanks.

*EDIT*

20 minutes later ac is cold.

 

[CJF]

the air got warmer like the compressor had stopped cycling.

Well, come on now...

Next time this occurs, pop the hood and see whether or not the compressor is in fact engaged.

Curtis

 

[fzj80kidpen]

Have you just tried adding a little can of R134?

 

[KliersLC]

Welcome to the "my ac works sometimes club" Without a set of manifold guages, you won't be able to determine the exact problem. May as well take it to an AC shop.....

Sorry,
Dan

 

[94landcruiser]

The odd thing is it never stops working when diving, only if I run it while idiling.

Guess I'll take it to a shop and get the R134 & pressure levels checked.

Can someone tell me which data from the FSM I need to print out so the shop has the correct values? (I have all the PDFs)

 

[Beowulf]

The odd thing is it never stops working when diving, only if I run it while idiling.

Guess I'll take it to a shop and get the R134 & pressure levels checked.

How is your A/C drive belt? OEM? Relatively new? Proper tension?

-B-

 

[94landcruiser]

Yeppers, oem, less than 3k on them and both are the proper tension.

 

[CJF]

Guess I'll take it to a shop and get the R134 & pressure levels checked.

Why give up so fast?

Knowing whether or not the compressor is cutting out will tell you a lot. Also, don't r134a systems have a sight glass like r12 systems? If so you can easily check that as another starting point.

Good luck,

Curtis
91FJ80

 

[94landcruiser]

The sight glass shows the proper amount of R134 and behaves as it should yet I am having problems. If someone has something else I need to look at I'll do it.

Thanks

 

[94landcruiser]

Printed the on vehicle inspection and followed all items I could (without gauges)

Everything is as it says it should be above.

No bubbles when ac is on, foamy for 5-10 seconds then solid when turned off, etc.

I waited again yesterday for my wife and this time kept the rpms above 1k (goes down to about 750 when the compressor cycles off) and did not loose my cool air for ten minutes.

 

[Tools R Us]

Is the compressor clutch disengaging when the vent temp rises? If it is, two issues will cause this, high coolant temp and/or high freon pressure. Both of these issues are airflow related, low airflow through the radiator will cause coolant temp to rise at idle or low airflow through the condenser will cause the high side freon pressure to rise at idle. If one or both rises past their switched value the compressor will be disengaged.

If the compressor clutch is disengaging, the first thing to look at is the fan clutch. If it's weak replace and/or upgrade the fluid, or add an electric fan switched to come on with the compressor, to improve the airflow at idle.

 

[94landcruiser]

When this happened the air became warm but the compressor did not disengage. The radiator was replaced/rebuilt in February by the po. He said the entire cooling system was replaced.

The weird thing is everything works perfectly until it idles as I said it did not do it when I kept the rpms up when the compressor cycled off. (causing the rpms to go back down to 750 from 1100 )

As a precaution after the first episode, I took the truck and had the radiator/condensor/trans cooler power washed, there are no bugs nor debris in the fins.

 

[Epic Ed]

How are you determining that the compressor is staying on when the cabin temp rises? Do the RPMs of the engine remain high like it should when the compressor is running? Or do the RPMs drop like it does when the compessor shuts off? FWIW, my intermittent issuess with the AC cutting in/out seem to have been due to over heating. I initially thought coolant leak, too, but a pressure gauge on the low-side port showed a full charge and good pressure. I then thought fan clutch, but ToolsRus helped eliminate that as a cause. Turned out I needed a new radiator cap -- cap allow air in, thus less effifient at cooling. Plus a couple of other minor cooling inefficiencies (foam around radiator not in place, low engine shield missing). Add in the ambinet temps around here are above 100. All of those minor challenges to the cooling system caused the engine to run a little hot while in traffic or when stopped.

I replaced the radiator cap and and topped off the coolant that seems to have solved most of my issues. I still plan to seal up the fan shroud and add an electric fan in front of the radiator to help the system stay cool here in the broiling desert temps.

Ed

 

[94landcruiser]

Thanks for all the ideas. My cooling system is 6 months old, I did the raventai gauge mod so I know I am running under 180 (it is like it is painted there when warm) the temperature here has been very nice, under 85 almost all summer.

I am not sure about the rpms when it stops blowing cold but I have checked and the compressor clutch is engaged.

As I said earlier I have been artificially keeping the revs up at idle (1000 rpm) when the compressor cycles off and since I have done that I have had no issues.

Seems the rpms may be going too low when it cycles off, is that possible?

 

[94landcruiser]

So this happened again while I was mostly keeping the revs up, and it stayed hot for a while. I need it fixed. The mechanics here will not be familiar with 80s so I really would appreciate any ideas as to where to point them.

As a recap the ac blows freezing cold until the car idles for 5 minutes or more with the ac on.

This was preceded by changing the hose that connects to the junction to the heater valve (small one from the firewall to the valve)

Thanks

 

[94landcruiser]

I think I found the solution (based on a limited trial) I installed an aux fan from my BMW's ac (I bought a complete front end for a body repair which included the condenser and it's aux fan) and still had the fan.

During a short trip wth the fan on I did not lose my AC. So to those that said warm condenser that seems to be it. Now the question is why?

 

[elhombre]

It sure makes me think that you have a problem with the fan clutch. I understand that your temp gauge does not move or show HOT, but your aux. fan test seems to point to lack of air movement. Locate the cut off switch for the A/C and put your test meter on it when the A/C cuts out. Or simply pull the wires off the cut off switch and short them to together to see if the compressor comes back on.

Hell, it's already September so you could just drink beer and mess with it next year .