Review on 🌡️ Enhanced Performance: OTC 7991 Cooling System Pressure Tester Kit for Optimum Cooling Efficiency by Edward Perez

There is no doubt that OTC products are not the best tools in the world, but they make very good tools at very reasonable prices. The 7991 is no different - it offers professional features at a do-it-yourself price. I'm glad I added this coolant pressure tester to my shelf full of OTC gear 'save my bacon'. ;) The best feature of this tool is the air chamber that isolates the pump from the coolant filler neck. While it's a little tedious to set the bladder at just the right height, it's far less of a chore than keeping track and sorting through a stack of fill adapters. Plus, you can have peace of mind knowing that this tool will likely work on almost every car that hits the road rather than worrying about having to buy more adapters if someone changes threads or diameters. (In my particular case, I already have a wonderful machine with a unique filler neck, so an OTC tool was the obvious choice!) Operation is fairly simple - adjust the depth of the bottle, adjust the height of the clamp, the slide pump the Valve to the "bladder" and pump air to the mark indicated on the pressure gauge - just a couple of clicks. Push the valve back and pump the cooling system up to the correct pressure (typically 15-20 pounds). Check for leaks or listen for hisses — and of course, remember that if you have a few problems, fixing one problem can lead to another. So repeat the test until the pressure drops. My only gripe with this tool is the slide valve. To be honest it sucks. If you don't have a quick hand, switching between Bladder and System can lose bladder pressure, which can cause coolant to spurt. Plus, the slider moves so easily it can be enough to land a fly—the slightest push results in the same coolant squirt. To use the pump effectively, I had to put a hand on the body of the machine - a slight tug on the hose moves the slider and then you start over (and make a mess). Likewise, there is an art to depressurizing a system - you have to carefully move the slider right to the center to release the pressure. Too little or too much can result in nothing happening or, you guessed it, a mess. The slider is a minor thing - I'm more than willing to live with that quirk given the tool's functionality, flexibility and price. This is a thoughtful design that just needs a little tweaking. Regardless, I found my leaks in minutes and saved myself hundreds of dollars at the store. It wasn't necessary for my application, but if you're having trouble finding leaks I'd probably recommend using cooling system paint and UV light in addition to this tool. It's cheap and can save real time.