jayk

I forgot to change my oil filter last time I changed my oil, what would happen if I just unscrewed the oil filter and put a new one on? Would oil go everywhere or just the little bit in the ends of the hoses?

impactwrench

Just a little bit

nopistons94

being that it sits upright, if you leave your car sit for a few hours it shouldn't lose hardly any oil at all if any. When I change my oil thats the first thing I do before taking out the drain plug and nothing comes out on a cold block

jayk

Cool, thanks.

DaveW

I don't totally understand your question, but...

If your oil filter is in the stock location, it doesn't matter if the pan is full or not. Just punch a hole in the top of the filter with an awl or a screwdriver to let most of the oil drain back to the pan, and put a rag around the filter base to catch the little bit that will still dribble out.

nopistons94

I never had to punch a hole in mine with the pan full and the drain plug in though? I had a little dribble but i didnt just rip it right out I let it drain a little

DaveW

Good filters have an anti-drainback feature to prevent the filter from emptying out between runs, so more will come out when you remove them if it isn't drained first.

quicksilver_rx7

^

Not sure what he refers to as a "good" filter. I use the Mazda filter. That's as good of quality as any on the market.

All you have to do is remove the filter. Oil drains down to the pan as soon as the engine is shut off.

DaveW

The OEM filter has the anti-drainback, some cheaper ones don't.

quicksilver_rx7

I'm not trying to start an argument, but I've never experienced that. I always get my car good and warm, shut it off, remove the filter first, then proceed to do the rest. Never had oil spill out of the filter. I use the OEM filters.

adam c

iTrader: (2)

An oem filter won't drain out right away. Let the car sit overnight, then put on the new filter in the morning. Obviously, don't start the car before doing this in the morning . The old filter will be empty. No mess, and no wasted oil.

DaveW

I always thought that it was best to drain the oil with the engine warm, just after running for at least a few miles, so that any crud is still in suspension, and comes out with the oil, instead of lying in the bottom of the pan, waiting to contaminate the new oil.

Obviously, you can't drain the oil coolers, etc., but every little bit helps.

quicksilver_rx7

You get a more complete drain when the oil is hot vs. cold.

jayk

Now if only I can remember not to pull the car out of the garage before changing the filter

My original plan was to run some cheapo oil through my newly installed but used r1 oil coolers just in case any dust or anything got in the lines while they weren't installed. Then change the oil and oil filter again to make sure everything was clean before I put in the expensive synthetic stuff. The amazing part was that after running the car for ~10 minutes with brand new oil, it came out black. I guess there was plenty of crap left in the system even though the oil coolers were empty. After all that I screwed up and forgot to change the filter.

Anyway, thanks for all the input guys.

adam c

iTrader: (2)

I like to drain the oil with the engine cold. That way, all the old oil has drained completely into the pan. None still in the engine lubing things. In additon, you don't have to deal with any hot engine parts or oil, and you don't have any oil in your filter.

I don't think so

BLKTOPTRVL

Always seems to be the case. Whenever I check my oil on the dipstick it can look golden, but if I drain it at the same time, it will look blackish.

quicksilver_rx7

How so? Ever tried to pour cold bacon grease out of a frying pan?

adam c

iTrader: (2)

Cold oil pours (and drains) just fine. If that were not the case, it would be difficult to pour oil from a new container. Most contemporary oils are made to pour and drain freely at anything but temperatures that are well below freezing.

KevinK2

1) at the oil filter base, oil flows in the outer small holes/slots, and exits the middle threaded hole. the rubber part that blocks the small holes is the anti drainback valve.

2) oem, fram, puro, etc, all have the same basic anti-drain back valve. This is to prevent draining of the oil supply path to the pump every time engine is stopped, which could then run dry a bit every start.

3) you can remove the filter hot or cold after a hot shutdown, and it will be empty. being "seal side down" near the top of the engine, oil trapped in the filter will have drained through normal paths, to turbos, e-shaft, etc, and will have been replaced by air from the crankcase. Oil on the outside of the filter element will flow to the center through the pleats.

4) I suggest routine double changes, esp with dual coolers where a single change only replaces about 75% of the old oil. I do 1st change warm/hot with new filter, run engine (carefully on jacks in my case) until oil filter/line is too hot to keep finger on, then just change sump oil ( ~3.8 Q's ). This assures over 90% change, and you will notice the diff when it is clear on the dipstick long after the change, and all fuel smell is gone.

jayk

What do you mean by "and all fuel smell is gone"? I noticed after my last oil change that I was getting a strong fuel odor when I first drove the car which has since gone away. I never thought to connect it with the oil change though.

Julian

iTrader: (14)

The two Oil Coolers hold back a lot of oil. KevenK2 double change should in theory get above 90%, but may be over the top. Oil change intervals includes delution accounting.

I do punch the top of the filter to get a full drain out .. but WARNING, punch to the outer edge on the top a direct stab in the middle inch dia can by chance punch the pressure relief cap out and fall down into the oil tube. Years ago, a Mazda factory race mechanic warned me that this has happened.

KevinK2

only time a hole would help, would be if you briefly started (and moved) a dead cold engine, esp with 15W50 in the winter.

when done as I noted, I never leak a drop. now my mazda 6 is another story ....

saburo

iTrader: (1)

oh my god its just an oil change!!

jic

iTrader: (1)

^^^ true that
but im gonna give it a shot and change the filter first next time
and see what happens