Stuff you find out by accident, haha?
2nd interval on fram ultra, 18k easy miles, the wife 100 miles a day on freeway, no go stiff as a rock, no vacuum issue or contamination, must have been in bypass for a lot of miles. Oil was in good shape amber still smelled good, that had 10k miles pup.
Here is the deal, I had rp canister next to fram ultra canister in my wifes trunk, I never thought about dry heat cycles, lol? The rp is the oldest filter, I bought ten years ago, still like new. However, I am on the end of a 6 pack deal I bought fram ultra and not used but also in wifes trunk the filter was stiff as a board, lol? Age and temp in rav 4 trunk stiffened fram ultra. Zero doubt rp has better media, just yet another of a long list of examples of this. Also, store your microglass filters indoors. I have 20 rp 20-820 so glad they are inside. lol. A hot garage or a hot truck can mess them up, not RP apparently, but other filters. with canister filters it allows you to see things you otherwise would not think about/.