94 Explorer EB A/C issue

What does red mean- too much pressure? That would indicate some sort of blockage, I should think. How that could happen on the low side of the system beats me. Maybe it was overfilled in the past?

-Paul

Now... how can I avoid telling you how inferior these cans are yet tell you how to reliably and effectively repair your system?

Your can "tells" you that there is a serious problem with your system.... Taking the can back for a refund and having the system repaired correctly is a viable option.

In the shop, we use some simple tests to determine our course of action... none of which include "topping off" the system. If the system is low there is a leak. Without proper testing, there is no way to judge the severity. There are other possible causes as well. Without the proper knowledge you run the risk of adding more damage to the system as well as releasing compounds into the atmosphere that could affect future generations.

For troubleshooting, I can only suggest that you gain a working knowledge of the system before you attempt further repairs.

Look why did you reply to my post. How helpfull have you been? Are you that person at work that finds something wrong with everything that anyone does?

Proper testing as you say is something that is understood in the back of my mind. I have spent thousands of dollars to pay someone such as yourself. I merely figured that I could get some feedback from people about what kinds of problems they have seen in the past with the symptoms being High Pressure on the low side. That is it. Not a lecture on how back yard mechanic my method is and what the correct way to troubleshoot the problem is.

I am so glad you made me aware of my options and the possible problems that I may encounter if I continue. I had no idea.......NOT.

Thank you but no thanks.

Sam in Raleigh.

To the others who posted a reply...THANK YOU.

Is it red showing high or red showing too low a pressure. When you lose freon it can make the low side go lower and I suppose they could show that as a low side red zone. If you feel the metal parts of the hose assembly as each pipe comes out of the compressor the high side should be hot and the low side should be relatively cool to cold. You can also feel the pipes where they go into the evap case by the firewall. The high pressure should be hot just before it gets to the junction where the orifice tube is and on the other side of the orifice tube it should be cold. If it's not pretty hot right on the inlet side but seems relatively cool it could indicate a restriction upstream in the high side. Don't recall if you can feel both sides on the 94's, I know I can on my S-10. You can also feel the outlet pipe from the evap and it should be roughly the same temp as the cold side on the input side. My memory says that if it seems significantly warmer in the outlet it's probably low on freon.

The other thing to look at is the amount of cycling the system is doing. If all is well and you run the engine at 2000 rpm and it's a moderate temperature day the clutch should cycle several times a minute. If it's really hot it might not cycle at all unless you are spraying water on the condenser. They cycle when the low side pressure drops below around 24 psi and come back on when it goes up to about 40 psi. The pressure is pretty close to the temp the evap core is at. So you see if you average 24 and 40 you get right at 32 degrees. Just at the freezing point of water. If it gets low on freon the pressures go low and on moderate temp days it can make the core too cold and that's why cars with low freon charges may freeze up on moderate temp fairly humid days.

My reply was, by no means, a lecture... when I lecture someone, they generally know they have been LECTURED.

My advice stands... gain a working knowledge of the system... if you want to fix it, you HAVE to know how it works.

If you look back, you did not mention anything about "high pressure on the low side"... this makes me bad??? If there is high pressure on the low side, it is going to be nothing higher than static pressure. At this time it would be real handy to know what the high side pressure is - but, since you appear to be an expert. there is no need of this piffling information... I'm bad... You don't mention if the clutch is engaging or not.... this also makes me bad....

Your original post is almost totally bereft of the information that will lead to a timely repair of your concern.... You are now in the realm of "it COULD be this" or "it COULD be that". Enjoy...

Freon. Isn't this the key word here? Doesn't a '94 have R12 in it? Isn't it really, really bad to put R232 or whatever it's called in a Freon system without completely evacuating it first?

Are we sure we have the right stuff?

it can make the low side go lower and I suppose they could

The 1993 model year was the last Explorer year to have R-12.

Well turns out the system was actually low on R-114. The reading on the cheap gauge was not accurate because of an issue with the low side tap on the evaporator. I found my hoses that goes to my gauges and hooked them up. Seems that there is an issue with the needle valve on the evaporators tap. Weird though as I cannot replace that valve. Isnt that valve replaceable on 94 Evaporator??? I tried backing it out but the needle valve tool that one uses to back the needle back out caught onto nothing and it did not turn.

Needless to say once I charged the system the A/C was cold again.

Now I am worried about the low side tap leaking.

I guess I need to buy another evaporator since I cannot get the needle valve out to replace it????

Making progress...at least the air is COLD since this week the temps will be 100 with heat indexes of 110. Just worried about the system leaking over time.

Sam in Raleigh.

Thanks everyone for your feedback!!!

Apparently this is the receive/dryer and not the Evaporator. I had some conflicting information for parts identification.

The receiver/dryer has a defective needle valve and I am unable to replace it. Some times the needle valve seats properly thus when I put liquid on the tap to check for moisture leaks nothing bubbles up but sometime after removing gauge hose the needle valve does not seat properly and I have to insert a small pin tip to push it down and allow it to spring back up to eventually the correct position.

This apparently is a suspected leak. Also not sure of the history of this device as it is rather shiny kind of looking like it was replaced by the original owner with hopefully the correct item.

Anyway just wanted to throw more info at you about what I am dealing with. Like I said the A/C is very very cold now but for how long time will tell.

I can take pictures and post here for your discussion.

Sam in Raleigh.

According to the Ford Service Manual the part is a accumulator/drier and sits next to the Evaporator at the firewall. This is the device that has the defective needle valve which is the low side tap.

If you are talking about the shrader valve that's in the low side fitting you can't take it out without all the freon leaking out in the process. There is supposed to be a cap that screws on over it. Inside the cap there should be a rubber o-ring. I don't know if they are supposed to be a perfect seal or not but you should be able to tighten it good and tight. If the o-ring is hard you might want to stop by a refrigeration supply house and get a new o-ring or a new cap and o-ring.