Replacing AC Low Side Service Port Housing

[sandrapaloma2001]

Hi all, Im new to this forum. I apologize if my post is in the wrong place. I have a 2003 Chev Suburban 1500 2wd 5.3 Flex Fuel Vin:Z with 180K miles. Problem: At present my finances, thus my diy attempt. Problem with Vehicle: Over a period of months my air conditioner slowly became less and less cool. I see refrigerant bubbling from Low Pressure Service Port and feel air pressure against my finger when covering the High Side Service Port. At the time my vehicle never stayed parked long enough (teens) to do any further checking. Now they have their own vehicle, time to see about my AC. I connected the manifold hoses and the system has no refrigerant in it, as I suspected once the compressor didnt try to cycle on any longer when turning on the ac. I researched “leakingAC service ports” and to my understanding GM’s ACs systems have faulty ball & flap style parts inside their service port housing that aren’t replaceable. However it is possible to purchase the housing which contain the ball and flap inside. By most accounts its a simple unscrew the old part and screw in replacement, just being careful to realize it unscrews in the center, and does not unscrew from the line itself.  At the auto parts store I told them I need to replace both my High & Low side service ports and they showed a me a kit which contained both housings (the fatter high side port and slimmer Low side port, both have a threaded end for screwing in as a replacement) it also contained red and blue caps and schrader valve cores. This was where I should have questioned the reason for valve cores being in the kit but I thought it must be an either/or kind of kit but everything I read said “Replace the port housing because of the faulty GM ports leak after disconnecting the manifold couplings” So with my system empty already, I unscrew the High side port. Replace with the new one, screwed right in, fit well. Then tried the same with the Low side port. After several failed attempts to unscrew it, its now rounded off, bent and still hasn’t budged. My Question 1:Does the Low Pressure Service Port (near the dryer thats wrapped in foil near firewall) {its the port where refrigerant is recieved into the system}  unscrew in the middle like the High Side port did, so that the upper housing of the port can be replaced?? Of course I have since seen the Low side port has a Schrader valve inside. Problem: Replacing Schrader valve may solve the leak problem BUT thats irrelevant when the system cant be recharged due to the manifold coupling not fitting well enough to seal because of the mangled upper half of the housing. 2: If it should unscrew, any suggestions what will loosen it? 3: If I have to replace the aluminum line where the low port is, what is the name of that line and should I replace anything else while Im at it bc Ive read some ppl say replace accumalator/dryer and orifice tube if the system is going to be opened at that point anyways? Any suggestions are appreciated I really messed up at first not paying attention if specific lines were referenced as I read about leaking AC service ports. Apparently most ppl experience with leaks are on the high side because when I tried to research specifically for the low side replacement, I can’t find anything about replacing the port housing, only the schrader valve, which has me thinking I might be looking at replacing the line due to my messing it up. I apologize about long post but wanted to go ahead and explain the long as the short might get more questions than answers. Also I have vacuum pump, and know how much refrigerant to recharge (134-A) just need to get Low pressure service port replaced if possible??  

[chem_man]

Hi Sandra,

 

Welcome to the forum.  I went to https://www.wholesalegmpartsonline.com/showAssembly.aspx?ukey_assembly=372163&ukey_make=1024&ukey_model=14543&modelYear=2003&ukey_category=19390&ukey_trimLevel=25304

to get a look at your lines and it does not look like you can simply unscrew the low pressure port off the AC line like you were able to do with the high side pressure port.  It appears that you will need to replace the entire AC line that goes from the AC Accumulator to the Condenser.

 

Here is a link to the Autozone website for AC line assemblies for what is likely your Suburban https://www.autozone.com/cooling-heating-and-climate-control/a-c-hose-assembly

If you do not have rear auxiliary AC in your Suburban, you will need to use the ACDelco 15-33436 AC Hose Assembly (or equivalent part from 4 Seasons, GPD, etc.).  If you do have the rear auxiliary AC in your Suburban, then you will need to use the ACDelco 15-33179 AC Hose Assembly (or equivalent part from 4 Seasons, GPD, etc.).

 

Remember to lubricate all the O-rings you come across with some PAG oil.  Also, replacement hose assemblies from ACDelco and 4-Seasons typically come with new, replacement o-rings.

 

Now to address how much R-134a you will need.  4 Seasons has a downloadable pdf that details how much R-134a in weight and how much oil your Suburban's AC system holds.  Here is the link to the page https://www.4s.com/en/catalog/catalog-resources/compressor-capacity-guide .  You can scroll through and see that your Suburban (assuming it does not have rear AC) takes 28 ounces of R-134a and 8 oz of PAG-46 oil.  NOTE:  Since you did not drain any oil out of your AC system, and keeping in mind that some of the PAG oil leaked out due to the leak in your system it might be worth it to add 1 or 2 ounces of new oil to the system by pouring it into one of the ends of the AC line you replace or by unscrewing the high side pressure port and injecting it in using a disposable syringe.

 

Good luck!

 

 

 

 

[sefiroxx]

Ditto chem_man

Also, the FSM manual provides hi/lo pressure readings based on temp and humidity. This will help to fine tune the amount of refrigerant

And, no, you don't have to replace orifice and accumulator for a minor leak. These usually are replaced when a compressor fails as it the failure sends material through the system that gets caught up the two components.

When replacing the pipes per chem_man, you might as well replace the orifice. It's relatively cheap, and if original, prone to failure via brittleness. When pulling the old one, check to see if it is whole (not throwing particles into the system)

[chem_man]

Just as an FYI, the ACDelco AC lines that I specified normally come with the orifice already installed.  I base this on having replaced the accumulator to condenser line on my 99 Silverado and an accumulator to evaporator line on my 99 Buick Century. 

 

Depending on how tight your budget is, I would go ahead and replace the accumulator because you are located in central Florida - lots of humidity and the accumulator is quite easy to replace (assuming your Suburban does not have rear AC).  If you were located in a less humid area then I would agree with sefiroxx.

 

Good luck!