OMT 3.5 CFM Single Stage Vacuum Pump for R134a R410a R22 Auto AC HVAC Kit

What Vacuum Pump. It arrived leak free, seemed very sturdy upon inspection. I used it on my truck today (1990 Chevy Silverado 1500 5.7L V8) and the A/C had been converted to R134a back in 1998. It was real easy to use with my OMT AC Manifold Gauge Set that I bought separately as I wanted better gauges than the ones offered by OMT kits. This pump is a wonder. It pulled a -30 inHg in about 20 seconds flat. Then when I kept it on for over 30 minutes to pull out all the air and water it got Semi-Hot but you could still touch it for a couple seconds to check the temp. Never got real hot at all. Actually it states it will pull a 5Pa but it looks like it will do a low 4Pa as my gauge went past the -30 into the black. Oil supplied was sufficient for a good between High-Low fill and it never moved from that position the whole time. Smoked very little upon start-up. IMHO this is a excellent unit and priced right for a DIY person. Need it - Get it..

I read reviews for a hand full of these pumps before purchasing and was worried about a hand full of things. I have done plenty of automotive A/C jobs and got tired of dealing with rentals or an air compressor venturi attachment. I decided to treat myself and bought this to make life easier. It works great and bottoms out the manifold gauges within a minute or two to boil off any moisture. I kept it on for 45 minutes and was all worried about oil clouds and misting etc, but this did not make any mess at all, nor use any oil at all. Maybe it was the environment, I’m not sure. For reference this was in Southern California and 82 degrees outside. It’s true the provided bottle of oil that comes with this is only enough to fill the tank half way to its capacity, but since it didn’t consume any oil for the job I am still good for the next one. This pump is whisper quiet as well, so I was able to talk normal around it running with no issues and the neighbors can’t complain. The casing was hot to touch as expected, but not enough to burn at all. Build quality is exceptional, including the plastic port caps. I was worried those would be brittle and thin, but they are heavy duty. No leaks at all either, and will update if I have any issues. Overall, just a great purchase!

Works pretty good and is a good price.

Quient and efficient. Motor got hot after 1hr of use but nothing wrong.

The vacuum pump is working good. After 15 minutes, it will smoke a little. Base on the other review, it is normal. That is accurate. Over all value is reasonable and get the job done.

This works good. I used it on a mini split and a few cars already. Not bad. Does the job for sure.

Quiet operation and serves the purpose. Seems to be of reasonably good quality for fairly my infrequent use. No complaints, especially for the price point.

I purchased the **Orion Motor Tech 3.5 CFM 1/4 HP Single Stage Vacuum Pump** expecting a reliable tool for my HVAC and auto AC needs, but this thing is an absolute **disaster**. From the moment I unboxed it, I could tell the build quality was subpar. ### **Major Issues: ** 1. **Cheap Materials & Poor Build** – The housing feels like flimsy aluminum, and the components seem poorly assembled. Within minutes of running, the unit started vibrating excessively and making a loud rattling noise. The handle even felt loose. 2. **Oil Leaks Everywhere** – After filling the pump with the included oil, I noticed **a major leak** around the sight glass and base. The seals seem non-existent, causing oil to drip constantly. I had to wipe the mess repeatedly, and after only a few uses, the oil was already contaminated. 3. **Extremely Weak Suction** – This pump claims to be 3.5 CFM, but in reality, **it barely pulls a vacuum**. I tested it on an AC system, and after 30 minutes, it failed to reach the proper vacuum level. Compared to other pumps I’ve used, this one **underperforms drastically**. 4. **Overheats Quickly** – After just 10 minutes of operation, the unit became **too hot to touch**. The cooling system is clearly inadequate, and I’m worried about long-term durability. 5. **Unreliable & Short Lifespan** – After a **few uses, it completely stopped working**. The motor struggled to turn on, and eventually, it wouldn't start at all. Contacting support was a nightmare—**they ignored my emails** and offered no real solution. ### **Final Verdict: ** This is a **waste of money** and a **frustrating experience**. If you need a vacuum pump for serious work, **DO NOT buy this one**. Spend a little more on a trusted brand —you’ll save yourself time, frustration, and money in the long run. ⭐ **Rating: 1/5 – Absolute Garbage. **

Muy buena bomba

Used this to pull a vacuum on my AC system before recharging. System held a solid vacuum. Vacuum hose connected to the pump with no effort and has a nice tight fit. It is affordable for someone like myself who’s somewhat of a DIYer and a home mechanic. It is a reliable entry level pump.

I'm a heat pump installation technician. This machine is of high quality and very easy to use.

Super genial

Va tres bien