Sherwood Cookie Jr. is the lead technician at Royalty Automotive in Georgia. Living in the South, Air Conditioning isn’t optional. But he still went on TikTok to urge drivers against buying an off-the-shelf A/C system recharge from an auto parts store. He has two reasons why this could cause you a major headache down the road.

First and foremost, what’s an A/C recharge? It’s a pressurized can you buy in an auto parts store that connects to your A/C system. It claims to top off the level of freon gas in your A/C system so your HVAC blows colder air. If you drive an old car, that may sound too good to be true. Sherwood warns it is.

1- “Biggest red flag” – A/C recharges contain “stop leak”

Sherwood searched the parts store’s shelf and only found one can of A/C recharge that didn’t contain “stop leak.” Stop leak is an additive designed to temporarily plug up a hole. A/C recharge sellers assume that an HVAC system low on freon must have a leak, so stop leak is always a good thing. The only problem is that it may leave the customer happy for one summer, but stop leak can eventually “plug” the entire system.

“You do not want to put stop leak in your vehicle. It’s going to potentially damage the vehicle.” But that’s not all.

Stop leak can wreak havoc on the machines that A/C shops use to work on your system. These machines can cost the shops fifteen thousand or more, so they aren’t taking any chances. Some shops “even have tests for it,” and if your car fails, you’re out. Other shops will “have you fill out something,” such as a waiver. If your system contains stop leak and damages their machinery, you may be on the hook to repair their gear.

2- Overcharging your A/C system

An A/C system needs a very specific amount of freon to operate correctly. Sherwood explains that to get the amount correct, he fully flushes a system, then recharges it with the exact right amount of gas. And the process isn’t easy.

“Refrigerant machines have a scale in them. There’s an interior tank and it weighs that. Some AC technicians will use a scale and they’ll have a cylinder on the scale. And as they’re putting it back in there, they’re watching the scale. And that’s how they know how much is going in there. It’s the only way you’re ever going to know that that system is full.”

What about A/C recharge canisters? The most expensive ones have a gauge that shows “low” “medium” and “full.” But Sherwood points out that it’s just a pressure gauge. The pressure of the air outside can throw them off wildly. “What’s the pressure supposed to be as compared to 20 minutes ago when it was hot outside? That pressure is going to be quite a bit different.”

Sherwood concluded, “People overcharge with these, and then the AC doesn’t work at all. You can overcharge, which could potentially cause damage. We see that a lot.” If a $50 A/C recharge canister was a reliable way to fix your HVAC system, why would your technician bother buying a calibrated, $15k machine to do the same job? You can see Sherwood Cookie Jr’s explanation on the Royalty Autos TikTok in the video embedded below:

@royaltyautoservice Waste of money! #diy #mechanic #automotive #viral #fyp #foryou #cartok #tips #stitch ♬ original sound – Royaltyautoservice