Subaru Forester Owners Forum banner

Oil filter question

(All Years) 
6K views 34 replies 11 participants last post by  nycredneck 
#1 ·
Just had a thought and was curious.
If synthetic oil changes are every 7 to 10 thousand miles, is it possible then if using conventional oil to just change oil at say 3,000 but leave the filter alone till the next 3,000 miles and then change both oil and filter? Filter would then have 6,000 miles on it and yes some of the oil would still be original that was left in filter from first change.
As I said just curious and wanted to hear your thoughts. At $5.00 a filter it's not worth it to actually do this.
 
#2 ·
Just had a thought and was curious. <sniip> As I said just curious and wanted to hear your thoughts. At $5.00 a filter it's not worth it to actually do this.
Yes, it would probably work. But why?

Subarus, particularly the turbo models, are rather oil sensitive. Change the filter when you change your oil and you can then worry about other things.
 
#3 ·
I've seen some oil analysis evidence to support that you can leave a filter in for multiple changes with no ill effects.

Despite this, I change the filter every time still. At $7.19 for a PureOne PL14460 (yes this filter fits the new models) it doesn't seem worth leaving it in, and risking failure.
 
#8 ·
Despite this, I change the filter every time still. At $7.19 for a PureOne PL14460 (yes this filter fits the new models) it doesn't seem worth leaving it in, and risking failure.

I use a genuine Subaru filter (blue) at a cost of $6.25 from Subaru dealer parts dept. New crush washer is about $1.20. Vehicle is leased and under warranty. I wouldn't take a chance using a non-Subaru filter just for the warranty's sake. They can't say the engine failed because you didn't use Subaru parts.

After the warranty runs out you can use whatever filter you want and put whatever type of oil you want.
 
#5 ·
I get my OEM filters on eBay, at $40.00 for 6 filters and change them out every oil change. With synthetic, which I plan on switching to, the filter stays in much longer so why not the same with conventional oil... Just saying, not doing.
 
#7 ·
I wouldn't, but your car is out of warranty I presume being a 2009, so it really doesn't matter.

If the vehicle calls for synthetic oil you use synthetic oil. There are properties of synthetic oil that conventional oil does not have and the reason the mfg. recommends using synthetic oil.

Your best bet is to change the oil with synthetic oil at the recommended interval and at that time change the oil filter also.

I change my own oil in my Forester at a cost of about $32 using quality synthetic 0W-20 oil and a Subaru oil filter (blue one).
 
#9 ·
I wouldn't, but your car is out of warranty I presume being a 2009, so it really doesn't matter.



If the vehicle calls for synthetic oil you use synthetic oil. There are properties of synthetic oil that conventional oil does not have and the reason the mfg. recommends using synthetic oil.



Your best bet is to change the oil with synthetic oil at the recommended interval and at that time change the oil filter also.



I change my own oil in my Forester at a cost of about $32 using quality synthetic 0W-20 oil and a Subaru oil filter (blue one).

The OP's car doesn't call for synthetic oil.
 
#11 ·
I change the filter in my Honda every other interval, as required by the manufacturer. I'm actually going to run the current Fram Ultra for a THIRD interval, because it's that good, and the engine is probably producing that little...

The oil left in the filter is pretty minor when compared to the oil volume. It doesn't matter, and if you're changing your oil ridiculously shortly, such as at 3k miles, then yes, running your filter for two intervals will probably work.
 
#32 ·
Interesting observations, NK. I will stick with the mfr recommended ADB valve in any case. I would not expect it to hold a column of oil above the filter but it does prevent the oil in the filter from siphoning down into the oil pan, which is a problem I have observed on my Ford van.

I stopped being super anal about oil and filters on my Forester after it got the head gaskets replaced, then the piston rings because the HG replacement caused it to use more than a quart in 1000 miles. Why the heck should I be anal about inconsequential differences between filters when my engine has already been torn down twice? The only reason anyone would need bigger filter area is because the engine is producing shrapnel or taking in dirt from the outside.

I'm using the dealer for oil changes (30 bucks with a free wash) and I would be reluctant to ask them to put on anything other than the blue OEM filter or one of my old Tokyo Roki's (that I bought from that dealer). We have run a couple Hondas up past 130k miles with virtually zero consumption and no engine problems using the Honda dealer's OEM filters (also Honeywell) and plain old Valvoline oil (which my Subaru dealer also uses). Seems like Valvoline has a monopoly on Detroit area car dealers...

Take care, and I do appreciate your verified observations using gauges as opposed to the typical "I don't see anything weird happening" with no verification.
George
 
#33 ·
The oil filter on the EJ is on the same horizontal plane as the oil pan, when the engine is off the oil drains to the filter or the oil pan. There is no possibility for oil to migrate from the filter to the pan unless the car is flipped onto the driver's side. I linked a photo for this to make more sense, it shows the exhaust removed. For oil to move from the filter to the pan without the engine running it has to travel about 3 inches up into the block and to the right. My apologies for not explaining what I was trying to get at better earlier.

http://www.vortechonline.com/engines/grfx/EJ25c.jpg

The reason the PL14660 has no valve is because it was designed for the EJ which has the filter in this location. OEM filters have a valve because on the H6 engine the filter has been mounted on it's side in some years. While the H6 does have a different filter OEM part number available currently, I would wager that they used to use the same filter on both H4 and H6 and that's why the valve was there.

Side question, how many miles were on your car when the head gaskets went? It sounds horrifying to have had to rip into the engine twice to fix those piston rings too...

Thanks for helping to contribute information to this thread, this is part of why I like this site much more than NASIOC :grin2:
 
#34 ·
Head gaskets were seeping at 72k miles but the last month of my 6/80 extended warranty. I told the dealer to look for any possible warranty work since the warranty was going away.

After the fix, the engine started using oil at an alarming rate and neither I nor the dealer (who is well regarded) could explain it--my best theory was that the cylinders got pulled out of shape by the head retorquing but the dealer swore engine was out of the car and torque sequence was anal.

I had been using Mobil 1 before and after the first HG change.

So I got new rings at 76k miles even tho my warranty was up--dealer got Subaru to pay everything except a 250 deductible for me (and I had Subaru Mastercard certificates so it did not cost me out of pocket). Picked up a bit of cold engine piston slap that I did not recall before the ring change. Dealer said the rings were sticking(!?) Looks like my oil consumption is less than a quart in 4k miles now and I'll accept that. It's been almost 10k miles since the new rings.

I had been running my Foz on full syn since 10k miles and have been anal about filters, but after this major engine stuff, have decided to go back to regular oil and not sweat filters because any miniscule differences are dwarfed by Subaru's major engine weirdnesses. I might not have bought my Foz if I knew that all EJ25's were still prone to HG problems--and they are. Stupid open deck design. (If I wanted to build a strong EJ engine I'd start with a turbo block.)

I'm 63 years old and have owned about 40 cars, drag raced, autocrossed, and have driven a million miles or so, and am glad to discuss. I have been on Internet forums for 18+ years and understand how to keep things pleasant even when I disagree with someone. I have no ego tied up in this, appreciate being corrected when necessary, and appreciate your illustration filter vs pan oil level...

Thank you also for your civility. I am also on a Ford truck forum that is amazingly civil and have made a lot of good friends there.

George
 
You have insufficient privileges to reply here.
Top