High side pressure?

91 OCC previously converted to R134A. With onset of summer decided to add rerigerant and check pressures, Using cheap high side gauge that previously seemed accurate and low side gauge included with can of R134A. Low side reading 45 psi but high side only 200-215 psi. Ambient temperature in upper 80's with high humidity. It's blowing cold as ever. Should I add more refrigerant? Buy a better gauge? Or leave it the hell alone? Advise appreciated.

If it ain't broke, don't fix it.

Tom

Leave it alone - If anything, you're overcharged if it's running 45 psi (~50F) on the low side.

Target 30 psi (~35F) on the low side

The 134a can gauge could be off too - what is the temp of the air coming out of the vents?

A low high side pressure is actually a good thing

Leave it the hell alone.

Those do it yourself cans should be illegal, lol. I suppose some folks have luck with them but our shop has 50k in machines for a reason.

Things have a sticker on them with the Freon amounts for a reason. Stabbing a hole in a can and letting her rip isn't going to result in that amount.

Your low side pressure is pretty much maxed, I prefer to see 30 to 35. High side is sort of high. On over the road trucks the fan will kick on around 250 or so to bring the pressures way back down.

Edit, if I had a dollar for every f'd up system I've worked on that had the "I add a can every time it blows warm" style of repair I'd be retired.

Thanks, gentlemen. I'll leave the system alone. I had [mistakenly] thought the high side pressure should be close to 250 psi on a hot day. This forum is very helpful.

as woody mentioned, i've heard many ac pros say the same thing about those do-it-yourself cans. they suck. the 'gauges' suck and best to spend the money and have things fixed right.

That said, i did use one of those cans on a friend's titan that wasn't blowing cold. Put a small can's worth with the sealant crap and they never had a problem again for the next 5 years they had the truck. Guess you get lucky sometimes, but i wouldn't recommend it anymore.