(Poll) Adding oil to oil filter when changing it
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I pre-fill the filters that are able to be installed straight up onto the engine.If the filter sits at an angle,forget it,it's goin on dry,not gonna make a mess if I dont have to
I would think the clean bottled oil poured into the filter outlet is cleaner than the dirty oil that is in the engine and old oil filter. Especially for those of us who run extended OCI's. I prefill my filters.
I prefill and have for decades. Not hard to do and likely saves a little wear and tear. Makes me feel warm and fuzzy at least.
In my wrenching career, I discovered it's a very good idea on some engines that have funky lubrication systems. The Rover V8 is one such. I have seen some that will lose prime if they sit with no oil in them too long. Sometimes it takes a long while to get oil pressure back up, lifters rattling the whole time. KInda nerve wracking. Filling the oil filter helps in that case. 'Course, I think that example is an extreme exception. Most engines come up to pressure pretty fast even with a dry filter. I like to see a study done on this but I'd guess, for most engines, it won't amount to much either way.
In my wrenching career, I discovered it's a very good idea on some engines that have funky lubrication systems. The Rover V8 is one such. I have seen some that will lose prime if they sit with no oil in them too long. Sometimes it takes a long while to get oil pressure back up, lifters rattling the whole time. KInda nerve wracking. Filling the oil filter helps in that case. 'Course, I think that example is an extreme exception. Most engines come up to pressure pretty fast even with a dry filter. I like to see a study done on this but I'd guess, for most engines, it won't amount to much either way.
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Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
Originally Posted By: Smokescreen
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
In one of these threads concerning this issue, someone said they couldn't tell a difference. I'd think a second or two would be about it.
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
In one of these threads concerning this issue, someone said they couldn't tell a difference. I'd think a second or two would be about it.
Originally Posted By: Smokescreen
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
I have paid attention to this in the past, and I estimate that the difference averages about a second. At 3000 rpm, that means that the engine rotates around 50 times more without oil pressure. Sure, there's a film of oil already in your bearings but you're spinning those bearings, cams and rings with only boundary lubrication. It's not hydrodynamic.
I always prefill my filters. Even if they install horizontally, hardly any oil drips out when installing it. On my Honda S2000, I have a prelube pump installed - I just flip a switch and pre-pressurize my entire system before I crank the engine.
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
I have paid attention to this in the past, and I estimate that the difference averages about a second. At 3000 rpm, that means that the engine rotates around 50 times more without oil pressure. Sure, there's a film of oil already in your bearings but you're spinning those bearings, cams and rings with only boundary lubrication. It's not hydrodynamic.
I always prefill my filters. Even if they install horizontally, hardly any oil drips out when installing it. On my Honda S2000, I have a prelube pump installed - I just flip a switch and pre-pressurize my entire system before I crank the engine.
After doing an oil change on my vehicles I always disable either fuel or ignition, and then turn the engine over with the starter for 5-10 seconds. The filter fills right up and the oil light even goes out. This is a great alternative for diagonal or sideways mounted oil filters.
Sounds like more work than needed to disable the fuel pump. There are many cars on the road that go to quick lubes that I doubt prefill and they are running fine.
Originally Posted By: Smokescreen
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
Your OP gauge will read some pressure just about as fast with dry filter. Unfortunately, its showing air pressure as the the oil is chasing the air out. The air and oil in the galleries will be the same pressure at that time, and the gauge can't tell the difference.
I pre-fill.
Has anyone ever timed the difference (between prefill and not) to full pressure to see if its noticable?
Your OP gauge will read some pressure just about as fast with dry filter. Unfortunately, its showing air pressure as the the oil is chasing the air out. The air and oil in the galleries will be the same pressure at that time, and the gauge can't tell the difference.
I pre-fill.
Depends on the car. If filter threads face upward I try to remember to pre-oil the filter. If filter mounts horizontally I would disconnect the spark plug wires and crank the engine over for 4-5 seconds which essentially does the same thing anyway. Either way, there should be full oil pressure when the car is started.
My cold starts in -30C (or worse) weather are more brutal than pre-filling my two ounce Yaris filter.
As always, YMMV.
As always, YMMV.
I can't say either way but considering the amount of air present pre & post filter after an oil change (w/ filter), I question the benefits of a few ounces of oil added to a horizontally mounted oil filter on startup.
Myself, I worry more about reducing the time from sump to pump on dry startup. As a result, I install the oil filter last after the oil sump has been filled (pull drain plug, remove oil filter, replace drain plug, add oil, install oil filter) thereby, in theory, allowing oil to displace air that may have been trapped in the oil pickup tube/strainer assembly by a restrictive oil filled filter.
Also if possible, I spin the engine with a non-chipped ignition key prior to the initial startup.
Myself, I worry more about reducing the time from sump to pump on dry startup. As a result, I install the oil filter last after the oil sump has been filled (pull drain plug, remove oil filter, replace drain plug, add oil, install oil filter) thereby, in theory, allowing oil to displace air that may have been trapped in the oil pickup tube/strainer assembly by a restrictive oil filled filter.
Also if possible, I spin the engine with a non-chipped ignition key prior to the initial startup.
I think spinning the engine without fuel or ignition is not needed and could cause more wear and tear on your starter motor. Since we all use quality oil that maintains a film on parts in the engine, there should be no wear on engine parts for the 1 to 3 seconds it takes (at least in my cars) for the oil pressure light to go out after changing the oil filter.
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