Hey all,

So i had been topping off my a/c annually, and this year it didn't take when they added a can at my local oil change shop. The compressor got really growly and they said, sorry take it somewhere else that compressor needs to replaced, you're looking at $2k.

So my neighbourhood shade tree mechanic concured the compressor was gone. I got one at RockAuto and he slapped it in. I took it for a recharge today, told them I had just replaced the compressor. The kid puts the can in and the air got colder, but not really cold. His supervisor comes over and says that they only top off the low pressure system and I need to take it a place that will do a proper recharge on the high pressure system too. $40, no big deal on my end, I knew it was a gamble jsut doing a top off.

So, my question, is it true that I should get it properly recharged? Kal Tire says about $200, and that's not flushing the system, just doing a proper top off. Is that top off different then adding a can to the low pressure side? Is it worth my money?

Thanks,

Justin

Nissan systems are all fairly touchy about the amount of refrigerant you add, the only good way to get it right with cans is to weigh the cans (which means doing a little math ahead of time so you know the weight of the can versus the contents). Adding some unknown quantity every year, you may well have overcharged it and not needed a compressor in the first place, or you may have killed the compressor with excess refrigerant. Overcharge will screw up the system just as badly as an undercharge, and in some ways worse.

That said, after a compressor change, if no one evacuated it before throwing a can at it, you probably have moisture in the system anyway. On an 11 year old car, get it serviced properly.

There are only two jobs that I don't mess with on any car, and I wouldn't take to any hillbilly shop. Transmissions and A/C. You want competent mechanics doing those jobs.

SPAM

Following up on this one, I did have Kal top it off $260. They did the negative pressure test for leaks (or whatever) and there were none. Spent the summer with great air conditioning. Here’s hoping it holds for next year.

The compressor still sounds pretty growly, but only at idle I believe. Can the low factory idle cause this I wonder? As in the growl goes away with increased rpm’s…?

Can the idle rpm’s be increased?

2012SV wrote: ↑

Thu Aug 24, 2023 6:46 pm

Can the idle rpm’s be increased?

The idle Rpm can be bumped up using 3rd party tools like UpRev, higher end scan tools like Autel or a Nissan Consult. But if you’re changing the rpm to make a noise go away sounds you’re just going to mask your real issues.

blink32 wrote: ↑

Tue Sep 19, 2023 4:01 pm

The idle Rpm can be bumped up using 3rd party tools like UpRev, higher end scan tools like Autel or a Nissan Consult. But if you’re changing the rpm to make a noise go away sounds you’re just going to mask your real issues.

+1, but the OP should first make sure the growl is actually from the compressor and not something else in the truck like a bad motor mount, bad tensioner, or a heat shield vibrating heavily with the extra load. Some detective work with a stethoscope is probably called for.