Per the replies below, if you have an oval collar or no collar you don't have the required adapter for the filter. Swedish Engineering (swedishengineering.com) sells both the adapter and filter or you can get both from the dealer. This is not an expensive kit and drops right in. I did it recently on my 94 and found a whole lot of crud waiting to push its way into the blower fan. It also keeps pollen from building up on the evaporator (i.e. pollen filter). It is a good time to vacuum out all the dirt, leaves, etc. that get trapped in that area. There is also a charcoal filter that will fit (again with the same adapter) that is supposed to keep odors out of the cabin, but I haven't tried that yet. It will be next.