The right filter for my Onan 5500. A little pricey for an oil filter but it does its job

Why does this filter sweat when it is installed properly. It's not that I don't know how to install a filter or over tighten it. I hand tighten them turn a 1/4 turn . If you make it tighter it will stop leaking but is difficult to remove. This is the only filter whether it's on a car or other generators that I encounter this issue.

This is the filter for my Onan 5500 generator. What can I say....it's a stock oil filter. But the Onan OEM filter is about 1/2 in longer than the NAPA replacement I used last year. And that 1/2 inch makes a big difference when it comes to removal because the generator has an air seal gasket that fits around the filter very near the bottom of the oil filter. The Onan filter is long enough that the filter sticks out below the air seal gasket to allow removal of the filter without putting too much pressure on the air seal gasket. The air seal gasket is getting less flexible with age. I am a fan of NAPA filters, but the NAPA filter forces you to temporarily distort the air seal gasket to get a wrench on the bottom of the oil filter. I'll pay a few $ more for the Onan. And Amazon delivered to my door.... where the local Onan parts place is hit or miss with it's stock.

came already used

Filter works as advertised. A little spendy but so's the Onan Generator you're putting it on. Some aftermarket filters may not have the same features that the factory filter has so I'll keep buying the Onan filter through Amazon.