Both sides Low

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, JohnHere

Post Reply
chromegsx
Posts: 1
Read the full article
Joined: Mon Oct 03, 2016 9:50 am

Both sides Low

Post by chromegsx »

I've been having some AC issues that seem to be getting progressively worse. I know I have a leak. But do I have a compressor issue now too? How would you proceed without throwing parts at the problem?

Vehicle: 2009 Dodge Ram 1500 Larimie Crew Cab 5.7L Hemi

It started over the course of the summer. AC seemed to get less and less cold and then finally was just no cold. I can remember when there were a few times were I'd pull out at a stop sign to go up a hill and the whole system would just turn off or slow down till I got to the top of the hill and the engine load would be back to normal. My dad has the capability and training to work on AC systems (but this problem seems a bit past his experience as he is suggesting throwing parts at it...expansion valve first). So I got it charged back at the beginning of August. It worked great, but only lasted for about 3 weeks. got it charged again and now it only lasted about a week or so. As suggested by my dad as possible easy/cheap fix...I bought some red devil system sealer with UV dye in and we were going to try that to see if it fixed it and showed us a leak if it didn't hold. Unfortunately when we hooked the gauges up this time to do so, we got very low high side pressure like 50 or less (forget the exact number but it was supposed to be well over 200) We added a bit of a charge anyway (I think about 12oz...system takes 26oz). AC clutch engaged, but this didn't bring the pressure up much on the high side (we added to low side). He then added just a small amount of refrigerant slowly to the high side (yes he knows your not supposed to do this) and the pressure came up a little but no where near where it needed to be. This was a surprise for my dad as he had never seen this behavior before (extremely low high side readings). We decided not to add any more refrigerate and not add the red devil either. We were thinking expansion valve was the problem, so we pulled it off but didn't find anything unusual...but we couldn't find a way to test them, so I figured I might as well replace it since they were relatively cheap. We put it all back together with the old expansion valve till I got a new one and ran a vacuum on it and It took maybe 10-15 min to go from vacuum of 30 to 10, confirming what we already knew...we had a leak. Well after some time to ponder the situation and why the high side was so low...I'm wondering if I don't have a leak and a bad compressor or restriction somewhere on the high side. So I'm wondering if there is any way to test the compressor for its compressing ability since that is not a cheap part to be just replacing and hoping for the best?? or is there a way to find a restriction as well?

Also I was getting an oily smell inside my truck when I'd run the AC or heating after the 2nd charge. I confirmed it was AC oil smell when I took the Expansion valve out to look at it and smelled the ac oil in it. Probably indicative of the leak but not sure.

Or are there any other suggestions...maybe just charge the system and run some dye in and find the leak. Would this still work if the compressor is not doing it's job of compressing? If so I could at least eliminate the leak and then continue diagnosis.
mk378
Posts: 77
Joined: Tue May 24, 2016 5:53 am

Re: Both sides Low

Post by mk378 »

You need a full charge to evaluate compressor performance, so yes like you said eliminate the leak then go from there. You will probably find the system is OK once not leaking and fully charged.

So, find the leak. When it leaks out that fast you can usually find it by just putting a little refrigerant in without even starting the engine or running the compressor, and go over the system with an electronic detector.

Do not use sealer, EVER. Your dad's advice is not in your truck's best interest.
User avatar
Cusser
Preferred Member
Posts: 846
Joined: Sun Apr 24, 2016 6:29 am

Re: Both sides Low

Post by Cusser »

mk378 wrote:You need a full charge to evaluate compressor performance, so yes like you said eliminate the leak then go from there. You will probably find the system is OK once not leaking and fully charged.

So, find the leak. When it leaks out that fast you can usually find it by just putting a little refrigerant in without even starting the engine or running the compressor, and go over the system with an electronic detector.

Do not use sealer, EVER. Your dad's advice is not in your truck's best interest.
This, above.
Post Reply