The Prius engine shuts down when not needed, and powers back up on demand, usually under load. It is critical to have an oil filter with a anti- drainback valve, which keeps the oil system pressurized so when the engine powers up its ready for a load with no lag in lubrication. If your not using a Toyota oil filter make sure the one you buy has a anti- drainback valve incorporated.I shopped at Wally World and found that there were two Fram filters that were listed for the Prius, but only one had a anti-drainback valve, the Fram tough guard has a valve. Like wise if you take your Prius some where to have the oil changed make sure they use a filter with a anti-drainback valve. if any one has found any other oil filter brands with the valve would like to know . thanks and heres to long engine life.
I admit I don't know a single thing about drainback valves, and they may, indeed, be important to have for the Prius. But not for the reason you state. The ICE does not start up under load, oil pressure is actual brought up via MG1 spinning up the ICE rpm to about 1000 rpm before ignition occurs. It's one of the beautiful engineering accomplishments of the Prius.
Now that was funny:rofl: A few things to consider why it doesn't matter about the ADBV: 1. The filter is oriented with the opening facing up so no draining of the oil occurs. 2. What efusco said 3. The elapsed time of the ICE cycling on/off is not enough to reduce lubrication on the metal parts. Oil clings to the metal parts for a surprisingly long time even though most of the oil is in the sump with the ICE off.
The vertical orientation of the Prius oil filter means that it remains filled with oil when the engine is off. This will not be news to Prius operators who to their own maintenance. Filter-mounting designs of other orientations are likely to benefit from anti-drainback valves. They can't keep the oil system pressurized (because it has a bunch of holes at the 'delivery' end), but they can keep a filter full of oil. (edit) I just noticed that was Steve's first post. Welcome to Priuschat and under the circumstances, I should have taken a more friendly tone. :welcome:
In fact the anti-drainback valve is one of the most over-rated selling points for an oil filter. I've changed oil on at least 20 - 30 different makes of cars and I would say that no more then maybe 20 % of them even have a filter that is mounted sideways and of those 20 % at least half of those are mounted more or less at about a 45 degree angle from the ground.
All oil filters I have seen have antidrainback valves. There must be reasons for that. From a layman's view, it seems more than if the filter is upside down or not. Let's say the pressure is 50 psi at engine shutdown. The column of oil is then going to bleed down fast, that's a lot of pressure. If the antidrainback valve was not there, just holes, all the dirty side of the filter oil could go back into the oil passages. If that reverse flow happens, it is like backflushing the filter dirt and oil back to the pan side. I am not sure it could happen this way, as the oil pump may have the most resistance to flow, but some thoughts on the subject.
Not all oil filter have a ADBV. I would say most do but not all. Some just have a by-pass valve, some have neither. You are current that the additional function of a ADBV is to provide a seal between the dirty and clean side but this is only important in horizontal or inverted filter positions. The reason most filters have a ADBV is most filters fit multiple vehicle applications and filter positions. It's just as easy to put one in so they don't need to go back later and make a new filter to fit a new application.
I have always used fram oil filters with no problems. Is there something I should know about fram that is bad for the Prius?
Yes, they are junk. Go to bobistheoilguy. There is a relatively new thread there with photographs of yet another failed Fram. "Friends don't let friends buy Fram oil filters." (Their air filters are OK.)
Open the hood and look for a large black rectangular plastic box. The top is secured with four metal clamps. Open the clamps and remove the top of the box. Lift up the paper filter and look at the bottom (which is the side that catches the dirt with 2G). Hold the filter up to the sun. If you can see light passing through, then you can continue reusing the filter. If the filter is dark, then replace it. I usually replace my air filter at 15K mile intervals.
It was brought up by someone else, but www.bobistheoilguy.com is to oil and filters like prius chat is to prius. Beware though if you really want to know, you will spend hours over there
Since this thread was resumed, I will say again, I have yet to see an automotive full flow oil filter without the ADB. Maybe people are looking for something inside the filter outlet hole, but ADB is covering the inlet holes. It is important for a Prius upside down filter to have the valve. The second the engine stops the oil above the outlet wants to go back to the pan via the filter inlet holes. ADB keeps filtered dirt in the filter and some oil in the line above depending on the design. It is a check valve and necessary.