air conditioning orifice tube location

[isham42]

i have a 98 Eldorado, 4.6L Northstar

i am looking for the orifice tube filter, i know its in the high side tube above the evap box but is it behind the fitting next to the high side port? i have to discharge the system anyway to put in a

low side temp sensor and i thought i would replace the orifice filter too. i just want to make sure were

it is before i start.

also the dryer, how long should it last, YEARS ? my car has almost 280k on it, should i replace it as well? a/c not working and trying to repair before summer, last year had leak but got that fixed.

thanks,

isham42

[Cadillac Jim]

If the system always held pressure and the problem is the compressor or clutch, the dryer should be OK. If you have had to add freon occasionally over the years or if it has leaked down to zero pressure and stayed that way for a long time, replacing the dryer-accumulator is a good precaution. Also, if the filter has anything at all in it, the dryer-accumulator will have something in it too, or be the source of the material, so that should be your cue to put in a new dryer-accumulator.

[BodybyFisher]

There is a pipe that runs along the firewall, at the center of the firewall is a fitting, its in that fitting. Here is a diagram of the 1996 system yours should be similar, you are looking for #2 - orifice tube, Mike

[isham42]

If the system always held pressure and the problem is the compressor or clutch, the dryer should be OK. If you have had to add freon occasionally over the years or if it has leaked down to zero pressure and stayed that way for a long time, replacing the dryer-accumulator is a good precaution. Also, if the filter has anything at all in it, the dryer-accumulator will have something in it too, or be the source of the material, so that should be your cue to put in a new dryer-accumulator.

my concern is that the orifice is full of ? and not allowing circulation, the dryer i was

thinking might be full of water or some liquid ? during the pre spring month of march

tried to add freon, warm days cold nights and the freon was more liquid than gas

i know i need a low side temp sensor and i need to open the line anyway, hince the

orifice tube, i have seen some dryers with a line or valve on the bottom of them, could

that be a drain ? or is the dryer on non reuseable part ? new on a/c

[KHE]

Is there a code stored for the low side temp sensor? Just wondering why it needs to be replaced as the failure rate of those sensors is quite low.

My guess is that the system is low on refrigerant and has disabled the compressor. If that is the case, you need to clear the code or the system won't pull in the refrigerant.

There is not a drain on the accumulator. I typically do not replace the accumulator unless the system has been sitting opened for an extended period of time.

A small amount of debris in the orifice tube screen may be present which is not a concern. If it is totally clogged, that's a different story. Remember to orient the long end of the o-tube toward the condenser or the low side temp. sensor will be destroyed.

[BodybyFisher]

Here is what my orifice tube looked like, needless to say I replaced the condenser, compressor, dryer and flushed the evaporator and line, here is the thread from my AC compressor replacementhttp://caddyinfo.ipbhost.com/index.php?sho...c=5846&st=0

[Cadillac Jim]

The accumulator/dryer is simply a tank that takes the output of the condenser -- the mass of pipes and fins in front of the car's radiator -- at the top, and at the bottom where there aren't any bubbles, liquid Freon goes to the expansion valve. It has a mass of silica gel in it to absorb moisture, as well as provide a baffle the keeps bubbles from circulating throughout the tank including to the bottom where they could get to the outlet and thus to the expansion valve. The silica gel absorbs any trace of moisture that finds its way into the system to prevent ice crystals from getting into the system and eventually clogging the expansion valve.

There are some traces of moisture in the system components when they are stored and shipped, and tiny amounts remain in a pumped-down system. Moisture can get into the system from traces of air that are in the hoses when a filler or checker system is hooked up to the system. Normally this isn't a problem because the dryer can absorb all the moisture that can get into a system during normal operation and maintenance over its lifetime. However, some conditions can overwhelm the silica gel in the dryer, such as a leak in the low side (typically a compressor seal or hose O-ring) while it is pulling a vacuum, or an open or leaky system sitting without being repaired for very long periods of time, or any other situation that circulates any air at all into the system.

Even when the silica gel is saturated, it won't block. What can happen to a system that causes debris include

• The silica gel in the dryer-accumulator, if left saturated or supersaturated, can break up and produce particles.
• Dirt or debris in the filler or checker hoses, or not cleaned away from the schrader valves when the system is hooked up, or lack of cleanliness in assembling or repairing a system can leave dirt particles in the system.
• The compressor can wear out or break down and produce metal or other particles. A common example is the reed valves that make the compressor cylinders pump gaseous Freon; eventually they break and these metal particles can result in other smaller metal particles being produced; this is one reason why the PCM shuts down the A/C and throws a code when it detects problems in the A/C.

If the system is very old, or the system has been left with a leak without being pumped down over a long period of time, the dryer should be replaced as a precaution, or because the silica gel is likely to be saturated. If the compressor has thrown any significant amount of debris that is seen in a filter, replacing the dryer will likely remove the rest of it, if you also flush out the condenser.

I don't like the idea of adding dyes or anything else to a system, particularly a newer one like those on Cadillacs that use a very small amount of Freon, because they dilute the Freon at best and provide a contaminant that won't evaporate, and that can't help the efficiency of the system. Perhaps a tiny additive to the compressor oil is all they are, but that ends up back in the compressor in normal use and won't be particularly good at showing leaks. In any case, a dye is worthless unless it can be seen, and most A/C leaks are trace leaks that are very difficult to see. Use a Freon sniffer.

[KHE]

if you also flush out the condenser.

I don't like the idea of adding dyes or anything else to a system, particularly a newer one like those on Cadillacs that use a very small amount of Freon, because they dilute the Freon at best and provide a contaminant that won't evaporate, and that can't help the efficiency of the system. Perhaps a tiny additive to the compressor oil is all they are, but that ends up back in the compressor in normal use and won't be particularly good at showing leaks. In any case, a dye is worthless unless it can be seen, and most A/C leaks are trace leaks that are very difficult to see. Use a Freon sniffer.

A little bit of misinformation here.

You cannot flush a parallel flow condenser - you'll never get all the flush solvent out of the condenser. The old serpentine condensers used with the R-12 systems were easily flushed but those types of condensers havent been used for about 15 years.

I don't understand your comments about refrigerant dyes... they are used in all HVAC systems and are not a "contaminate". 1/4 oz is all that is used in a system and refrigerant dye is approved by the major automakers - it is compatible with the refrigerant oil. The compressors do not have a sump like the old A-6 compressors of years ago. A small amount may collect in the compressor when the system is turned off but it is quickly circulated the instant the system is turned on. Most oil will collect in the accumulator when the system is turned off.

As far as dye not being good at showing leaks - simply not true. An electronic leak detector will show where the system is currently leaking but UV dye will sho where it has ever leaked. There are some leaks that are difficult to find or that will only show up when the system is in operation. That is where the UV dye really helps.

I use both an electronic leak detector and dye - If I can't find the leak with the electronic leak detector, the system gets dye. The dye always reveals the leak.