My 22re engine has overheated for years whenever the AC was used on a hot day. This overheating problem was very elusive to isolate. I changed many cooling system parts, which helped somewhat, but never solved my overheating problem on very hot days!!! Now that my truck IDLES UP properly with the AC on, no more overheating problems at all!!!! This AC Idle-Up Diaphragm increases your idle by about 100 rpm when the AC is turned on. Otherwise your AC is turned on and it loads the engine down terribly, which causes overheating. This is an amazing Upgrade to any older 22re engine!!!