Aftermarket Fram and Sierra oil filters dont pass muster with Practical Sailor testers.
Weve followed countless debates about the best engine oil and the right time of year to change it, as well as quite a few debates about oil analysis. Just as controversial is the advice on oil filters, which ranges from a blasé recommendation to use whatever fits, to an adamant insistence to use only original equipment manufacturer parts (OEM). Because the oil filter is sealed in a cartridge, unless your filter leaks oil into the bilge we never actually know if it did its job or not. Given the filters important role, this is unsettling.