Kennz - try reading!

Someone said the newer ones did not have the copper tube.
The copper tube type was used clear back in the RENIX days to at least 20005. Not all of them did, just some. That includes YJ's Cherokees, GC's, TJ'S etc. All very similar systems.

When you don't know something all you do is make a fool of yourself!

 

the tube thing every ones referring to is thermostat all cooling systems have them

 

Dont use stop leak, i can and will plug up the orfice tube causing the ac to not work. Also if you ever take it to a shop make sure they know it has stop leak because it is undetectable and will destroy a 4-5 thousand dollar ac machine. Also when you added R134 were you using the small cans? The reason i ask is because they have oil added already. Filling a system with little cans is a great way to overcharge the system with oil and will cause the system to not function properly

 

'00-'01 XJ efan turns when a/c pressure reaches X psi or when coolant temp reaches 218. '99 down XJ efan turns on when a/c compressor engages or when coolant temp reaches 218.

 

I guess I should have been clearer.
ALL SYSTEMS USE A THERMOSTAT to prevent icing up.
The long copper "capillary tube" pokes into the evaporator coils to sense when it's too cold. It controls by changing the expansion valve orifice - under the hood.

The other type of thermostat mounts right on the evaporator - with a shorter tube - it's electrical - signals the PCM to shut off the compressor clutch when it gets too cold.

The normal compresor cycling is not from the t-stat's - it's governed by system pressure.

BOTH types have been used on JEEPS for a longtime.

 

Ordered the switch described in the above thread. Will post results when it comes in.

 

KAHN SORRY FOR HIJACKING YOURE THREAD
rrich perhaps youre statement pertains more to yourself than me
hate to get in a pissing contest but there is no thermostat mounted in the evap. and since i just changed my evap on my 98 i can say with certainty that there is no thermostat mechanical or electrical mounted on the evaporator coil the temp is regulated by the blending of warm air into the a/c stream via the blend door, the only thing that cycles the compressor are the pressure switches.with over 30 years in the hvac trade i feel confident the above statement is correct at least on my vehicle and everyone elses i have seen pictures of
SO NO THERMOSTAT TO PREVENT ICING UP ONLY LO PRESSURE SWITCH AND NO EXPANSION VALVE ITS A FIXED ORIFICE

 

I'll post a picture of it from the FSM. First gotta figure out how to do it - it's on a CD.

The Fixed Orifice - that IS the expansion valve! 30 years?

Yes, interior temp can be regulated by the blend door(s) - but I don't think Jeep ever did it that way. Don't know on the ones newer than 05 - may even be associated with the PCM - They love making things way more complicated than needed.

======
Funny how some things can be so timely.
Yesterday a friend had the “stops blowing cold after a few minutes” problem. E-fan was fine.
I thought icing was the problem - no!
Normally when it ices up and you stop and shut it down, you get a big puddle underneath from the melting ice. This one didn't. The puddle was normal sized.
Parking for 10-15 minutes or so melts all the ice on the evaporator - or should if it's a warm day (yesterday was about 110 degrees here.) So it should blow cold for a while after restarting before it ices again.
This one didn't. Even after 15 minutes it still blew warm - even a little warmer than it normally would for a moment at first.

The heater core takes longer to cool down than the ice melting. What was happening was the blend door was only partially opening. When the engine was cold the heater core takes awhile to get warm, so the AC works for awhile. Then with the blend door partly open, both cold and warm air mixed.
After stopping the core was still warm, so it did not blow cool.

Upon inspection - I found a $20 bill rolled up jamming the blend door. Apparently his little girl dropped it down the defrost vent and it worked it's way down to the door!

Who would have thought?

 

an expansion valve and a fixed orifice are two totally differant animals.
an expansion valve has the ability to open and close(hence the term expansion) to allow more or less refrigerant into the evaporator based on evap temp which in turn reacts with a refrigerant charge located in the sensing bulb thereby creating a more constant evap temp regardless of temp or pressure on the hi side. There are 2 types adjustable and non adjustable.
simply put an orifice is just that, a hole that dosent change. yup 30 years
and yes that is exactly how the temp is regulated by either the addition or removal of warm air via the blend door, ill go out on a limb here and say thats how every non sophisticated automotive hvac system works. pressures cycle the compressor, air temp is changed by BLENDING warmer air into it. why would they call it a blend door if not for that reason

 

This is from a '95 FSM - Cherokee - it shows both types, but in actual practice, only one was used.

He He -- Not as easy to copy as I thought - printed it from the CD, then scanned it. Must be an easier way.

 

""""""an expansion valve and a fixed orifice are two totally differant animals.
an expansion valve has the ability to open and close(hence the term expansion) to allow more or less refrigerant into the evaporator based on evap temp """""""""

30 years and still never learned.
Expansion Valve is NOT because it's variable in size.
EXPANSION refers to where the hot liquid gas EXPANDS to the gaseous state, pulling heat from the system.
Whether it it's a variable sized orifice or not is irrelevant.

Obviously you never learned that in 30 years.
Look at any parts supplier - look up "expansion valve" they'll show both types.

 

lol i have no idea what vehicle that is from but it sure as hell aint a cherokee. maybe one of those big old wagoneer type cherokees but not an xj

 

ok you win on the reason its called an ex valve ill call myself a ******* on that but i stick to my guns on the rest, true a txv is an orifice but its not called an orifice. txvs are flow compensating and fixed are not,period

 

Go look in your own FACTORY SERVICE MANUAL for Yours! It will have the same diagram. Don't have one? Maybe that's why you don't know?
This diagram is for a 95 Cherokee - Didn't they stop making the big Wagoneer years before?

Notice the blend door(s) are set by the position of the dash control slider via a cable up till 02. At that time the position became controlled by a 2 way push-pull electric motor (more complicated to do the same job,) - but still controlled by the dash slider. No actual Thermostat involved.

The variable orifice capillary tube or the small switch on the evap (also with a capillary tube too) are simply there to prevent icing.

Refer to ANY book or manual on AC.

 

sir, it clearly says YJ on the diagram we are not talking about YJs here i dont need the friggin manual i just had my dash apart and that aint what it looks like in there not even close what exactly do YOU do for a living


heres my manual pic