1988 E150 5.0
All new parts in AC system.
This is only the 3rd with the new system working. From another thread, some of you might know I swapped out the clutch plate because it was making too much noise when it kicked in and out.
Any way after I finished the work, I noticed the system doesn't teem to be cycling. The clutch stays engaged unless I turn the AC control to off.
It has a new Motorcraft R12 cycle switch on the dryer.. I meant to pull the plug and make sure the clutch stopped but i forgot.

The outside temperature today is 94, humid, and very sunny. As the van is is in the sun, it too is quite warm inside. It does cool down inside to a comfortable temp after driving a while. I will check the vent temps in a couple of hours. I had forgotten my thermometer earlier.

I did put my very old yellow jacket gauges on (new hoses) that have been hanging in the shop for almost 20 years unused..
At idle, I don't have a tach, guessing 700rpm's, The high side pressure was 240 and the low side was 39.
Reeving the engine up and the low side would drop to around 25 and the high side stayed about the same..

I thought I might have heard it cycle a couple of times the engine had been off for 5 minutes and I started back down the road and was still in second gear.

Whats your thoughts? Too hot to cycle? maybe the pressure cycle switch is bad? What should I do next?

I know the charge was correct. 3.5lbs of R12 according to the book. That was exactly 4 fourteen ounce cans, if my math is correct. I lost a little the first time I removed the high side line...

It is my understanding if it is overcharged, it might not cycle correctly and if it is undercharged, it will cycle more the lower it gets..

Thanks for the help
Anna

 

I'll go with high heat load, and engine at idle. A/C Performance tests are usually done at least 1500 RPM, and may need to set a fan up in front. Trying to simulate road conditions. At idle, no air movement through the condensor other than what the engine fan can move. And the hot radiator is back-heating the condensor, to boot.

High humidity vastly increases the heat load. The Latent Heat of Condensation.

And if we add to that a bit of a breeze from the rear, and add a hood open so the cabin air intake picks up some engine-heated air, and we have the worst operating condition for an A/C unit, performance-wise

For the fun of it, at idle, you can try spraying some water into the condensor through the grill with a hose. A wide fan spray works the best, really trying to get a zillion small water droplets all over the grill area. It also cleans a dusty fan off

With a van, I would imagine one would want to have the inside engine cover in place while doing it, unless the interior needs a good cleaning, too!

 

Thanks again Torky2

Well I found out the clutch is cycling at times, you just cant hardly hear it. I was next to one of the concrete mediums with my window down and could hear it as the engine rived up starting off from a stop..

So I guess now is about the inside temps...
High top conversion van 138 wheel base with no rear AC or heater
As only the front windows open, the van was probably well over 115f when I started off on my trip.
97f outside,,
After 1/2 hr on the freeway at 55 to 70mph, the vent temps were at 50F

my thermometer is about 1.5" in diameter on the face so i stood it up on the carpet behind the passenger seat so air wouldn't be blowing directly on it. The inside air temp there was still almost 90F

So i am certainly not seeing those 34F temps out the vents i see people posting...

I have to make the same trip in a a few hours and the outside temp will be closer to 80F with no sun. I will see what the vent temps are then and report back..

let me run over this one more time on charging the system..

in the spec chart in the service manual it said
Oil- 10oz (new)
I took that to mean 10oz total for a new system.. That is exactly what i added..

Freon R12 3.5 lbs + or - .25.. I added 4 14 oz cans, that equals 3.5lbs

Then i lost some when taking off the high side line the first time. If i had to guess that loss was 2 to 4 ounces. (of course i have no reference from experience to estimate it!) if i was to bet on it, I would say closer to 2 ounces...

So if i understand this correctly, lets say the + or - .25 = 4 ounces
I would still be at the bottom of the specs on charge even if I lost 4 ounces when removing the high side hose. And that is also providing all the 14oz can really had 14 ounces in them. (when i was younger i used to drink a good bit of beer in 12oz cans so i could probably have guessed within 1/4 oz how much was in the cans. But I haven't drank much at all in the past few years and lost that talent!)

At this point i am thinking i could probably be safe in adding 6 ounces to the charge? Maybe?
Would that make any difference?

The problem is that I only have the little 14oz cans.. I could set it up on a set of scales and measure the amount that leaves the can but i don't know if i could save the balance of the r12 as I used a side can tap and it would probably leak out later on down the road..

Alright
Thanks Again
Anna

 

You're welcome!

OK on oil amount, OK on your math.
I doubt too that you lost 4 Oz. disconnecting at the HI side, 4 Oz. would have resulted in frostbite!

I never see center vent temps down in the 30s here in TX in the summer. Too high of heat load.

What was the system setting for that 50 degrees? Normal? or Recirculation?
Engine heat heats up all the air intake and some of the distribution ductwork. And also taking in outside air will limit the cooling delivered.

Jumping over to residential A/C for a moment, as it's easier to explain there, a home A/C unit in good condition will be capable of dropping the air temp 15 to 20 degrees F. across the evaporator. This is measured at the evaporator, but if a return air grill is close to the unit, inlet air temp can be measured there. Outlet air temp can best be measured by inserting a probe thermometer into the airstream in the supply plenum. Or at a register, if really really close to the unit and duct/trunk is well insulated. All this is to show that output air temp will be a function of intake air temp. As the space to be cooled cools down, then intake air is cooler, therefore output air will be cooler. A feedback effect. A house, in effect, is running on "Recirculate" all the time.

Back to vehicles, running outside air also means constant humidity coming in. When water vapor condenses, it releases a large amount of heat, which will limit the cooling. Running in Recirc, if the recirc door closes tightly and the seal on the door is still good, will in time allow the system to reduce moisture, without a lot more humid air coming in to replace it, therefore, vent temps will be lower.

I would monitor it for a few days, and try recirc if you have not run with it.

All mine are R-134a now. I keep an empty can that I wrote the weight on the side of it. I can use it to check the amount in new cans. With a digital scale, I can set the old empty on it, Tare it away, then set full can on it, and read the amount of refr. directly (or use simple math for the difference if your scale can not Tare).
For weighing how much you used out of a full can, now partial can, you need the weight of an empty can, plus the weight of your can tapping setup too, because that is going to be on the can with the valve closed to weigh it without losing it.

EDIT: Forgot to mention about fan speed. A lower fan speed will usually result in lower vent temp, but that is counter-productive, as moving a small amount of air per unit time through the evap to get a low vent outlet temp will result in a hot vehicle away from the vent!
I learned (OK, it took me quite a few years to learn it!) that after getting in a hot vehicle and getting the A/C going, to move the fan speed higher up than usual, as soon as the air temp out of the vents came down just enough as to not cook my eyeballs with the fan revved up. Later can move fan speed down some, but still maybe higher than "usual" depending on the heat load at the time.

 

Recirculate, I haven't tried normal yet


When I went at 1am and drove the same rout I had earlier on the freeway The outside temp was the inside and outside temps were about 80F then. Almost the same results as earlier in the day after i returned from the trip and the van had cooled down a little inside.

I also went out again this morning around 8am when the outside temp was 75F. Of course the van cooled down faster as it too was around 75F inside but the vent temperatures were about the same after a 8 mile trip. Still 50F out the vents maybe 48F



Thanks for taking the time to educate me on this as well as the home ac system! I hadn't thought about empty can and marking the partial can..


Now that it was cooler the clutch was cycling at idle.
Yes i achieved 44F out the center vent with fan on low, recirculate, idling in the driveway. It took some work to get the 44F though and it was just briefly. I have a heavy duty fan clutch and it seems to stay engaged at a little higher RPMs then the stock clutch. After I returned from my 8am trip, i sat in the driveway with it idling and noticed the temp went from 50F to 48F. I am going to guess that is because of the longer cycle time at idle and i had turned the fan speed down to low. I raised the RPMs a little just after the compressor clutch cut out and lowered the RPMs back down the second time the compressor reengaged. This caused a little longer run time for the compressor before it cycled off again. I did this a few times and the vent temps went down to 44F. That is the lowest i could get it..

I am thinking that it might need just a little more R12.
I am also guessing that every time you hook the gauges up to the low side without having a can of freon connected to purge the hoses, that it would suck in just a little air if from that single blue low side hose and the valve closed on the gauges...
I have only connected the gauges once to recheck the pressures and that was yesterday..
I am thinking the proper way to avoid this is to connect the can of freon, get the hose nut started on the suction line, then purge both the yellow and blue hose. Tighten the connection on the suction line just as freon starts to come out...

When i originally charged the system I closed the gauge valves, disconnected the vacuum pump and connected the yellow hose to the freon can. Purged the yellow hose at the gauge set, then opened the valve to start charging the system. I purged the line each time i changed cans..

I have not checked for leaks with the system charged. I did leave the gauges on for about 4 hours after I finished vacuuming the system and the needle did not move at all, even tappping the gauges to see if the needle was stuck..
I also used the nylog (snot) on all the connections.
All of the new parts had green o-rigns on them but because some of the parts may have been 10 to 15 years old, i changed out the o-rings too,, all but 2 of them that were on the evaporator core because I couldn't quite make up my mind if I had the right size replacement ones. I did remove them with the plastic removal pic and as with all of the o-rings, rolled them in the snot between my fingers and installed them!

There is one connection I forgot to check, a compression coupling on the condenser. At the bottom of the condenser where the flow leaves it, there is a compression connector that connects a hard line that runs to the opposite side of the condenser for connecting the hose that goes from the condenser to the evaporator.

Do you think I need to check for leaks with a leak detector? The torch ones are fairly cheap or i might be able to drive to a shop I know and see if they will let me use theirs right there at the shop...

Again thanks for all the help and taking the time to educate me on AC systems...
Anna

 

Hmmm, I didn't expect that!
Is your fresh air/recirc door actually moving to the Recirc position? Usually, when in Recirc, the fan sounds a lot louder, as the recirc air intake is just above the passengers feet, and that makes a short direct path for fan noise to come into the cabin. Switching from Recirc to Normal usually results in a noticeable drop in fan noise, as the inlet path from the cabin is then closed off, and air taken in from outside instead, so the fan-noise direct path disappears.
I don't know how the vans are of that vintage, but F-Series and Bronco tend to have a white plastic vacuum hardline that runs from the climate control head to the Recirc/Fresh Air vac motor under the hood on the fan box, go bad. They go crumbly right where the hose exits from the harness under the hood. I have had to unwrap the harness a bit as the hose turned a sort of dirty color and was crumbly for a few inches under the wrap too.

That could be.

Good! You are now one of the probable few who do not routinely blow a nice slug of air into their A/C system.

I'm thinking that is unlikely when connecting hoses to a pressurized system. Let's say that the LO side system pressure is 60 PSI. The blue hose is 0 PSI. Attach the hose. The refr. gas in the system enters the blue hose and compresses the air in the blue hose until equilibrium is reached. The gauge then reads 60 PSI. Then, say, the compressor engages and let's say the LO side pressure drops to 30 PSI. Refr. gas in the hose closest to the service port will return to the system, and the air slug further up the hose will also expand too. But unless there is significant mixing of the refr. gas and air in the hose, the hose at the service port still has refr. gas in it there.
The question would be "how much mixing of two different gases occurs in a long cylinder of very small cross-section (the 6 foot hose) when the second gas is introduced at one end?" My guess is very little. If instead of a long thin hose, the blue hose was something like a tennis ball instead, then I would expect A LOT of mixing!
I do have to say, that after hooking up gauges to a pressurized system, I DO purge air out of both hoses by bleeding air out one at a time, using the system pressure as the purge. For instance, Crack open LO manifold valve a tiny bit with yellow hose not connected to manifold. Then close valve and do same with HI side valve.
I've never seen a residential A/C service guy do that, but I do. Note that this method is very controlled, no fiddling with hose connector on service valve port when attaching hoses.

Leak Testing - I have an electronic sniffer, it is hard to use. Moisture can set it off. Wind, or fan airflow makes it for the most part useless. It WAS good for sticking up an evap condensate drain once with a system OFF and dry, it screamed then due to an evap leak. Evap leaks are hard to find!
For every fitting that I can possibly get to, brushing or spraying on a liquid dish detergent/water mix, with a higher than normal concentration of detergent, works well. Just like testing gas pipe connections. If it works for the ultra-low pressure of natural gas pipe after the regulator, works great for lot higher pressures of A/C. I use an inspection mirror to see all the way around the fitting and an LED pencil flashlight.

 

Yes it opens and closes, I am not sure if it is all the way. When I had the evaporator box off i cleaned out the opening. I should have checked the seals and all better while I had the chance..

Not so fast... I do remember the first can I attached, I did purge the hose from the can to the gauges but I did not purge the hose from the gauge set to the suction line.. So I did get a little air in the system that one time... I know better now..

That is what I will make sure I do from now on when I hook up the hoses to just check pressure before i start the engine and turn the compressor on..

Well now, that I know how to do and hadn’t thought of it, Thanks! If there any leaks they would have to be very small as I don’t think I have lost any noticeable gas. The compressor was cycling this morning but the outside temp was 75 and the van was cool inside too. The vent temps were still holding at 48 to 50F. I had hoped it would be cooler..
50F is pretty cool when the inside temp is 100 though!!!

So I guess unless you say any different, the plan tomorrow is to,
1- Double check and make sure the fresh air vent is opening and closing.
2- mix some soap and check for leaks.
EDIT forgot to add
3- use scales and add 5ounces of r12 and recheck pressures and vent temps

Thanks again and have a wonderful week!
Anna

 

Well I am watching it for a few days. As noted in my last post, this morning it was around 75F outside and inside the van and the vents were 50F, 48 if i played with the gas a little..

This afternoon it was 94F and the van had sat in the sun. The lowest I could get the vent temps was 52 and that was going down the interstate for about 15 miles of so..

i stopped by the mechanic shop and he let me use his leak detector in their driveway. i may have been using it wrong but it went off on 3 different hose connections and around the cutout switch, also sticking it back around the evaporator housing.
it also went off a couple of times just in the air outside the engine compartment.

When I got home I found a bottle of leak detection liquid for gas lines. I tried using the little dobber brush but wasn't sure it was getting in the connections enough so I put the liquid in a spray bottle, shook it up and sprayed the concoctions, nothing, no bubbles. the liquid did quickly evaporate though as it was so hot..

In the morning i will try spraying with a liquid soap mix. The outside temps will be round 75 again in the morning and I will see if i can get the same vent temps as i did this morning...

I am hoping i didn't screw up on the connections. I put the NYLOG on the O-rings but not inside the female side of the tubing..

What do you think of my adding some UV dye to the system?
If so how much and is there a special dye for R12?
Will any black light work?

 

I'm a bit skeptical that you would have that many leaks. The detergent solution should confirm or deny.

When I used the original Nylog on R-12 system, I don't remember if I tried to work some down and around the female side of springlock couplings. That was many years ago now! Oh that stuff was so stringy!

I don't know on the dye, whether it is universal, or if it is different due to the different refrigerant oils used in R-12 vs. R-134a. Research item!

Any UV light should do... do you have a couple of those 40 watt 4 foot long fluorescent blacklight tubes left over from the 1970s?

If you don't find any leaks with detergent, and you don't think you've lost any, then a leak does not seem to be the cause of the issue at hand.

With the humidity up, are you seeing significant condensate water dripping out from underneath, like just after returning from a trip?

 

I was surprised too that the electronic leak detector went off that much. It didn’t go off all the way around the spring lock fittings, just in one spot on them. I forgot to use th detector in the vents..

I only put it on the O-Rings and made sure my hands were clean when applying it. I had a hard time deciding on a couple of the o-rings. One of the parts was dated 2001, that is 15 year old. Maybe the old o-ring might have shrank a little?

from what I have been reading, here is a warning first: “There is also a risk of using too much dye. Though leak detection dye is compatible with refrigerants and compressor lubricants, adding several successive doses of dye in an attempt to find a leak may increase the risk of plugging an orifice tube or reducing the lubricity of the compressor oil. If someone has already added dye to the system, don't add more. It only takes a small amount to reveal a leak, and adding more won't speed up the process or make it any more effective.”
I am still looking for information on compatibility with dyes but Oreilly’s ac dye says on the package that it works with r12 or r134

NO,, mine got lost over the years!

What is the odds of a new evaporator leaking,, 4seasons brand?

yes there is lots of condensate water when running and just after cutting the engine off. The suction line and dryer is also condensating quite a bit too. there are 2 suction line hoses. one that connects to the dryer and runs under the crowl over to the drivers side and turns out for access to connect the manifold suction hose. IT is also condensating a good bit at the connection on the drivers side.


The shop up the street does not have a machine to reclame R12. I am thinking that If soap does not revile a leak, there is a old ac shop next door to my radiator shop that might have the equipment. If so, i may ask them about injecting some dye as by the time I buy the dye and injector, it might be cheaper to let them do it..
I believe what I read was a 1/4 oz of dye is what is needed. Perhaps it could be poured down in the blue suction hose, connected to the system, then add a little r12 but that would leave a little air in the blue suction hose as I wouldn’t be able to purge the blue hose after adding the dye..

 

Just an update and I will edit this post and update it through out the day...

outside temperature at 7am this morning is 71F and I left the windows down last night so the inside is about the same temp.

With the hood opened and the engine cold, after running about 10 minutes, the vent temps were at 42F on max ac with the fan on high.

When driving the temperature raises to 50F highway or in town..

Once back home with the hood up and the engine hot, vent temperature stayed at 50F

Still dripping condensation but not near as much.

It appears that the vent temperature rises with engine rpms as the compressor cycles more at higher rpms.

Will use soap spry and check for leaks after the engine cools back down and report back..


EDIT
Almost two hours later and the outside temp is 75F with high humidity of 83%
Engine was still warm when started this time and vent temps only went down to 50F
Mixed soap and sprayed all but 2 fittings that I could not reach and no sign of leaks.
learned that shaking the spray bottle so that it sprayed a bubble foam seemed to work best for filling the spring lock connectors.
Started the van and turned the AC on and sprayed the two high side connectors I could reach and still no leaks.

The only two I cant reach have the spring locks facing away from sight. 1- the dryer where it locks onto the evaporator
line and 2- the high side line where it locks onto the evaporator tube.

Perhaps I can remove the air box and use a inspection mirror to connection #2
Don't know how to spray connection #1

The compressor itself I have not checked for leaks

Called the old AC shop and they said to be there at 8am in the morning and they should have time to check it for leaks. They also can pull out the r12 if needed..

Perhaps there is no leak and just need to add more r12...

 

I should know better then to take my van to a shop!

SO I got to the shop by 8am like they told me and they said they were still covered up. He suggested a shop near my house so I went there.

The guy used his electronic leak detector and couldn't find any leaks.. I go to watch that part then they said I couldn't stay in the shop... I told the guy I wanted to add 5 ounces of R12 to the system and he said ok...
He added the whole 14oz can... SO now it may be overcharged.... And I need to remove 8 ounces....
I ask him to shoot a little dye in the system and he forgot to do that...

I did get him to leak test it again once he moved it out of the bay and he did, still no leaks. He used the leak detector at the suction connection to double check that it was working and it sounded an alarm there but no where else..

I ask about the condenser and not having dye in the system. He said if it is leaking I would see oil and dirt spots in it... and not to worry..

Today it was 94 and 43% humidity coldest vent temperature was 52F using my thermometer.
The guy at the shop used a digital laser and said it was 46 down in the center vent..
When i come to a stop for several minutes, the vent temp rises to 58F
And that's the situation now...

 

Just a random thought, it might be worth your time to check the blend door if you haven't already. If it's opened even just slightly to the heat side you are not going to get ice cold air.

(off-topic) most of my first legal driving was in a 88 E150 with an 351/C6 with Mom in the passenger seat and eight siblings in the back..... Miss that old van, it was a surprisingly fun vehicle to drive.

 

Thanks,, Yes I checked the blend door and it opens and closes all the way. I was also thinking about the duct work but it is blowing 0out the registers just great..

Last pressure check was 40 on the suction side and 210 on the high side with outside temps at 94F with vent temps at 52F on high with engine idling and a fan in front of the condenser..

Tonight with outside temps at 78F, inside van temperature at 83F, sitting idling vent temps were 52F Playing with raising the idle slightly and then dropping it after I hear the clutch click out, it went down to 48F. Let it idle by itself and it's right back to 52F
52 seems to be the magic number for some reason.

Seems like if there was a restriction, say condenser or orifice tube, that the high side would be higher? the low side would be lower?

 

I have been thinking about this and have a couple questions.
-what did you recharge the system with? R12 or 134a?
-if r12 was it the real stuff or the questionable stuff you find on the Internet that may or may not work?
-do you have front and rear air or just front? And are you positive you used the correct amount for the system you have?.... They use different amounts.

40psi on the low side at 90° is about right for 134a but I think 40psi is significantly overcharged on R12.... I'm very rusty on R12 but I think it should be more like 30-35psi.... Don't take my word for it, it's been a long time since I've touched stuff.