I've been doing some research on oil filters and came across several posts about Prius owners using oversized oil filters. That came as a huge shock to me. Is this practice safe? Wouldn't there be a loss in oil pressure? How does it fit? Why not use the OE size, but in a K&N or Mobil 1?
I think some people feel that having more surface area is better in the longrun. When individual pleats start to clog as the filter ages there will still be more places for the oil to run through. If your filter is all the way clogged it stops filtering and oil bypasses it. I agree with your second thought, seems to be way more important to just buy a high quality filter and good oil.
I'm not among the group that uses the longer Toyota filter, but it is only about 1/2" longer. Additional engine oil is added so that the dipstick level is correct. The fit is the same as the shorter filter. There should be no impact on engine oil pressure. Besides increasing available filtration, another motivation for using the longer filter is to make the filter easier to access when removing it, since much of the filter is surrounded by the engine block. This is not an issue for me since I use a cap wrench to remove and install the filter. Its not obvious to me that K&N or Mobil 1 filters are better than Toyota-branded oil filters. The Toyota oil filters are available for $3.29 each when buying a case of 10 from Toyota dealers selling discounted parts over the web. See for example: http://preview.tinyurl.com/32yw54 Speaking of K&N, I do not believe that its oiled air filters are suitable for modern fuel-injected vehicles equipped with mass air flow sensors, including Prius. I know a couple of posters who had to have their sensors replaced due to oil contamination. Those filters might be OK if you have an old VW carbureted dune buggy.
I like the slightly longer OEM Toyota filter simply because it's a little easier to reach and for the oil filter wrench to get a solid purchase on it. The extra filtration surface doesn't hurt matters, either, especially since the longer OEM filter is exactly the same price as the short OEM oil filter that's technically correct for the Prius application.
I use the Purolator Pure One PL20195. Compared to the stock filter, it's huge - about twice as long and slightly larger in diameter. Why use it? 1) The Pure One filters are (according to their specs) very good filters and filter down to a very small particle size. 2) A bigger filter has more filter area and can hold more particulates. I want this since I'm using Mobil 1 Extended Performance 5w-30 and using 10k mile oil changes (if Blackstone Labs says it's OK, I will go to and stick with 15k mile oil changes). 3) Oil pressure is not an issue - the thing that keeps oil pressure up is the resistance to oil flow of the crank bearings in the engine - not resistance (or lack of it) in the filter. 4) A subtle point: If you use a bigger filter, then your engine takes 4 quarts - you don't have to worry about 3 and a fraction. 5) A bigger filter doesn't cost more than a smaller filter. 6) This filter has an anti-drainback valve as required. 7) Same threads, same bypass pressure. 8) The gasket is a bit bigger in diameter, but it still fits well and seats snugly on the filter site. You asked, those are my answers.
I had a 1990 Toyota 4Runner V6, purchased new. In '95 I put on a bunch of Downey parts (Front torsion bars, rear coils, headers, etc). I tried their cone style air filter, which really did help performance compared to how the stock filter sucked in air from around the driver side headlight That Toyota had a vane style MAF. Imagine my surprise a couple of years later when the MAF buggered up. The K&N allows just enough oil carryover to clog a vane MAF Never again
Question . . . Anyone know for SURE if the larger Toyota filter body actually houses a larger filter membrane? What piques my curiosity is the fact that many "D" size batteries actually have smaller sized batteries for their internal parts. Claim: Trickery In Energizer D-Cell Rechargeables | Gadget Lab from Wired.com
The larger filter is 2/3" longer than the correct filter (another member recently sent me the larger filter for evaluation.) Looking inside the filter (without cutting it open), it appears to be fully populated. Unlike with consumer products batteries, there's no economic incentive for Toyota to be tricky with the larger filter. The price is the same as the correct filter. Toyota incurs a substantial warranty obligation on the powertrain, and will want its oil filters to do their assigned jobs.
I bought mine at Pep Boys. They're not at all uncommon - I am sure that you can get them at almost higher quality auto parts shop.
I've seen them as well oversized and wondered first if you do a regular oil change/filter, why bother? I change the filter every 5k, add oil and drive on. Synthetic Mobil 1. 15k change oil and filter. It's actually clean at 15k but I realize it breaks down. Does a larger filter mean go further between oil changes?
Your only issue is going with a too small filter, a filter that does not filter at the same required level, or a filter that is physically unable to fit or does not create a proper gasket seal. Other than this you will need to make up the amount of oil to accommodate size difference. Looks like this thread is from 2010 and I am wondering if there is any update on this?