Proper way to do oil changes

[kosteniuks17]

Stupid but maybe reasonable question,

I saw on some random thread on the internet that when doing your oil change it said something about the air filter having air in it so you have to put oil in the filter or something. It said on initial start the engine will push air out possibly causing premature wear. Idk if this is true but if you drained your oil and then started filling the oil back up wouldnt the oil fill in the oil filter. I just wanted to know how the professionals do it. Not sure how you all do it. just planning to do an oil change in the next few weeks.

 

[kosteniuks17]

Originally Posted by Zippy452:

sorry if it has been answered but i didn't want to read all the way though all the pages. I skimmed like 5 of them. Why do you fill the filter with oil? Is it this model car? I just ask as I have never done that to all my cars i have owned. I have put oil on the seal to lube it up and provide a great seal (something i do with almost any seal) but never filled the filter with oil.

Reply to post:
When the oil pump first fires up after a change, you want it pushing oil, not air. For old guys or the guys taught by old guys, filters used to install sideways conventionally, so it wasn't really done often. But even the boys on "Wheelers Dealers" rehab car show recommend the technique. If you can prime the oil system, do it to reduce wear and increase your longevity (and car value of course).

 

[Cheap5]

I ONLY do this to diesels that will allow it. All your engine parts will be. Lubricated regardless of the filter being filled prior to. Unless it has been sitting for a very long period. But I do suggest changing it hot or shortly after driving. The oil drains better that way.

 

[RyanY]

when doing your oil change it said something about the air filter having air in it so you have to put oil in the filter or something.

I'm assuming you mean the oil filter - your air filter should not have oil in it unless you have an aftermarket oiled cotton performance air filter (like a K&N) installed on your car, and oiling that is a completely different process.

What you were reading was talking about priming your oil filter when changing your oil to reduce the amount of time before the engine builds oil pressure. When you install an empty new oil filter, the engine's oil pressure has to fill it up with oil before it starts flowing to the rest of your engine, i.e. bearings, etc. As much as 90% of the wear on a engine occurs in the few seconds after it is first started and before it builds up oil pressure - pre-filling your oil filter, even partially, will significantly reduce the amount of time it takes for your bearings to see oil pressure after you change your oil.

 

[grcy_gttr]

So for the P5 owners, how is this possible, if our oil filters are inverted?

 

[kosteniuks17]

Yah thats exactly what I was thinking. Thats why I said as we fill up your oil, then wouldnt it fill up the filter as well. I understand priming it if its on the bottom but wouldnt it just pour out when you put our oil filter on.

 

[rit14623]

So for the P5 owners, how is this possible, if our oil filters are inverted?

That's true. If you ever remove the oil filter after the car has not been running for awhile, maybe overnight, the oil filter will be empty. There's no point in filling it up before putting it back on because it is just going to drain out and down while you are screwing it back on, which creates its own mess.
It is true that the oil will be drawn down by gravity and the engine will be running without oil in the cylinders for a short time when you start it up. This is why synthetic oil is good. It will stay on the metal surfaces unlike regular oil.

 

[pcb]

Most (if not all) oil filters have an anti- drainback valve that's supposed to keep the oil in the filter.

A used oil filter should feel heavier than the empty new one.

 

[hornsfan10609]

I have done countless oil changes on Mazdas and I have never primed the oil system or 'bench bled' the oil filter. I don't think it does any damage the motor is still coated in oil on initial startup, not to mention 99% of all oil changes are done without pre-filling the filter and I don't see engines failing left and right because of it

 

[rit14623]

Most (if not all) oil filters have an anti- drainback valve that's supposed to keep the oil in the filter.

A used oil filter should feel heavier than the empty new one.

I use Fram filters. Every time I change the oil in the protege5, it's light and empty. But, when I change the oil filter in my MPV, it's heavy and full of oil. Same thing with my other cars, the oil filter is heavy with oil when I change it out.

 

[RyanY]

I have done countless oil changes on Mazdas and I have never primed the oil system or 'bench bled' the oil filter. I don't think it does any damage the motor is still coated in oil on initial startup, not to mention 99% of all oil changes are done without pre-filling the filter and I don't see engines failing left and right because of it

Using that logic, every person that's primed the oil system on their newly rebuilt engine before starting it was wasting their time since all the engine bearings should have assembly lube on them, right?
The oil film on bearings doesn't stay in place for more than a few revolutions once the engine has been started and the thousands of pounds of force from combustion pressure is being transferred through the rods, into the rod and main bearings, and squeezing out any existing oil film. The quicker an engine starts pumping oil into those bearings, the less wear is going to occur.
I used to work at a quick lube place (before the 10 years I spent working at a dealership) and never primed a filter or an oil system either, that doesn't mean that it's the best way to do an oil change, just the most time-efficient. For the small amount of time and effort it takes to do it on my own vehicle, I'll do what I can to reduce the engine wear - it could well be the difference between an engine that goes 150k miles vs. 200k miles.

I'll pour an inch of oil into the bottom of my filter and rotate it around so the oil is absorbed by the filter media, that way none spills out before I can tighten the filter back down. On my turbo Miata with 210K miles with it's remote mounted filter, I'll fill the filter completely before installing it since the filter is right side up. On my 95 Montero with 241K miles and a horizontal filter, I'll fill the filter half full then rotate it to soak the filter media before installing it. In my opinion it's a pretty easy way to reduce the engine wear on startup, but to each their own.

BTW, Fram filters are generally some of the worst oil filters you can use. Do some reading here for real testing and analysis of which filters are the best to use based on construction quality, filter media, and drainback valves.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=postlist&Board=6&page=1

 

[kamesama980]

So for the P5 owners, how is this possible, if our oil filters are inverted?

can't, really, with a sideways or inverted filter.

Yah thats exactly what I was thinking. Thats why I said as we fill up your oil, then wouldnt it fill up the filter as well. I understand priming it if its on the bottom but wouldnt it just pour out when you put our oil filter on.

you won't fill the filter as you pour oil into the engine because the filter isn't just stuck to the side of the block for oil to drain through. to get to the filter backwards, it'd have to squeeze into the bearings, through the passages, then into the filter. nevermind there's a positive displacement pump on the other side blocking it.

I've worked in oil change places, dealerships, and went to school for auto repair. Never filled them at work (course most aren't vertically mounted). Away from the shop, I fill em up if they're vertically mounted.

Working on big diesels now, SOP is to fill em up. they hold more than a quart of oil on a 15l. 'Course it'd probably prime itself as quickly as a car since the pump is proportionally larger too.

 

[mp5la]

I usually fill the oil filters before I install them with fresh oil. I'm not sure if it makes much difference in terms of protection, but it does help with the oil level on startup. 9 times out of 10, once I recheck the oil after firing the engine up I'm still spot on since the filter was filled from the beginning.

And I agree about Fram filters. I wouldn't use them on anything I remotely cared about. I'm not saying you have to get a $15 filter, but at least get something that's decent.

 

[pcb]

I use Fram filters. Every time I change the oil in the protege5, it's light and empty. But, when I change the oil filter in my MPV, it's heavy and full of oil. Same thing with my other cars, the oil filter is heavy with oil when I change it out.

I use Fram Extra-Guard oil filters for the 626.
They are always heavy with oil.