Some time back I installed this fan. The fan does not blow in. It blows out the front. I use it when I first shut down. It sucks all of the heat out of the heat out of the engine compartment. It also pulls air over the mufflers so my floor does not get hot. It does a very good job. The only problem is that when I hit some truck stop for lunch I dont want to let it run for a hour while I eat. I have also been know to hit a campground and forget to turn it off for a couple of hours. I honestly dont yet know how long I want it to run---that will take some research this summer.