2006 Baja Low Oil Pressure

[cas5259]

Hey, I've got an EJ253 SOHC with low oil pressure that I need some help with. The pressure light was coming on below 1.5k rpm when warm. I changed the oil with some 0W-40 I had laying around and replaced the filter. Now the light only comes on below 1k when warm. Couldn't find anything wrong with the sender wire. There is no noise coming from the heads or any other unusual sounds indicating oil starvation. Oil and coolant are not mixed, and the levels have not moved. No smoke coming out of the exhaust...the thing drives just fine.

 

I hooked up a manual gauge to the sender port and got 10psi cold startup, which then dropped to almost 0 after a few minutes of warming up. Revving between 3-4000k rpm raises the pressure to about 22-25psi. Removed the oil pan - pickup tube looked fine.

 

Next up was the oil pump. The screws were all tight and I had to use an impact driver to remove them. There is some wear on the contact surfaces, but everything else looks fine for 150k miles. Is this enough to cause significant pressure loss?

 

 

There have been no smoking guns like I was hoping for. What else is there to check? Am I looking at a bearing issue and short block rebuild? Thanks.

 

 

[1 Lucky Texan]

double check the oil pick-up - look here; http://photos.killerbmotorsport.com/GalleryThumbnails.aspx?gallery=244340

 

any chance PCV and breather hoses have been misrouted? I read one thread once where that messed with oil pressure readings.

Edited July 6, 2016 by 1 Lucky Texan

[montana tom]

Hate to say, but low pressure usually ends up being bearings. Having said that, for apx 154.00 bucks you can get a brand new subaru high volume oil pump on ebay   from subarupartsonline  ( 131638875556 )  Yours should not be weak after only 150,000 miles but it could be. If it is bearings and you choose to rebuild then having that new oil pump will be money well spent. 

[cas5259]

Thanks for the input. I will clean up the pickup better and check again with a better light. Looking at those photos, I could have easily missed it because I was looking for something way bigger. I'm pretty sure I checked all the breather hoses, and there was no nasty sludge in them either.

 

Would a high volume pump be a short term solution? I do understand that the bearings will not fix themselves, but that could buy some time to gather rebuild parts. Assuming the crank is ok, could I just order a stock sized bearing kit, swap those in, then call it a day? 

 

With the oil pump off, there is a very small amount of radial play in the end of the crank. There is no axial play. Not sure how much is acceptable.

Edited July 6, 2016 by cas5259

[montana tom]

IF it is the bearings then the oil pump will do next to nothing. Sadly subaru bearings are not all sized the same ... you must disassemble to find out what size they put in yours ....crazy...  If the rods haven't spun then good chance the crank should be ok.  Really LONG day to split a subi case and do a rebuild and reassemble,  they definitely are not a chevy S.B.

[Fairtax4me]

Pull the pan off, look for chunky sparklies.

Remove the pickup tube, check the screen for debris that could block flow, check for cracks, and check the o-ring where it sticks up into the block.

[cas5259]

There was no metal flakes in the oil or the bottom of the pan. From what you guys have provided so far, the game plan is to a install high flow pump + pickup tube and o-ring. If that doesn't solve it, then a rebuild is in my future.

 

What else is involved in the rebuild that may not be obvious to a first timer? I have done a manual trans rebuild and EJ25 head gaskets, so I'm sure I can handle it with enough time. I'm thinking that a weeks worth of 3ish hours in the evening, then maybe a weekend will be enough time. Are there any special tools needed? When does a machine shop need to get involved?

[1 Lucky Texan]

is there spring in the relief valve that could be broken? I read of an RS owner that found his OPRV stuck open.

 

anyway - good luck with it

Edited July 7, 2016 by 1 Lucky Texan

[montana tom]

Look for and watch several youtube videos on splitting & reassembling the case. Biggest problem I ran into was the case bolts are really on there, Had to use an assistant to hold the case and a very powerful 1/2 " impact to get them free. Metric allen wrench (large) can't remember what size, you'll need it to access the piston pins. Small internal slide hammer is nice for getting the pins out but can be done without. Regular piston ring expander, and ring compressor. Plastic gauge to check bearing clearances.   I'm sure others will offer additional tips.

[cas5259]

The relief valve looked closed to me, but again, I don't have any experience with these oil pumps. I've got a 1/2'' electric impact with something like 700ft-lbs that has yet to be defeated. Thanks for the tips, we'll see what happens next week when i have time to put it back together with the new pump and pickup tube.

[cas5259]

Received the 11mm pump kit yesterday, thanks for the link. Got a new pickup tube and o-ring from the dealer and cleaned up the pan/block/pump surfaces last night so I'm ready to go for tomorrow. Hopefully this is the fix!

[cas5259]

Things started out good, then went south. 70psi cold start up, then fell down to 10psi as the engine warmed up - double what it was before. When fully warm, it dropped to 7psi. Still ok, so I installed the regular sender and went for a drive. After 20 minutes, the dash light started flickering when stopped. It goes off at 1000 rpm. F&%K!

[Fairtax4me]

Sorry for the bad luck. She's just been running low on pressure for too long.

 

Easiest/cheapest probably to pop a used engine in it.

Rebuilding isn't entirely difficult but will be time consuming.

[cas5259]

My only holdup about a used engine is the unknown history and how long its been sitting. I'd rather have the piece of mind and either rebuild it myself or find a re-manufactured short block and swap the heads onto it with new gaskets all around. Does the short block have to have EJ253 stamped on it? From what I've seen, all 2.5's look the same.

[matt167]

You can use any EJ25 shortblock including the EJ25D short block ( not reccomended ).. The pistons might have different volumes so your compression might change a little but for the most part 2000+ blocks can be interchangable

 

If you would like brand new you can get an EJ257 straight from the dealer for about $1,800. You would need to locate high compression pistons ( EJ257 uses shorter rods so N/A pistons won't work or can't be verified for every case ). But that gives you a brand new shortblock.. N/A blocks for the most part are listed as remanufactured thru the dealers so not 'new'.

 

Beyond that, get a price quote from CCR

[Fairtax4me]

Before you go getting a short block you should pull the cams out and check the cam bearing journals. The cams ride directly in the cylinder head, no replaceable bearing, so if the cams get starved for oil the journals get scored and the heads are useless after that.

[cas5259]

Before you go getting a short block you should pull the cams out and check the cam bearing journals. The cams ride directly in the cylinder head, no replaceable bearing, so if the cams get starved for oil the journals get scored and the heads are useless after that.

 

The first step will be to remove/disassemble the engine and confirm route cause. Thanks, I will check the cams and journals. The heads didn't have abnormal noises coming from them so I'm hoping they're fine and its just the main bearings.

[montana tom]

It should be the rods not the mains.But change out both. Be sure to order half block o rings and case bolt sealing washers before reassembly . Here is the link for them on ebay 142038603617 and 131655496434  same company, subaru parts online.  You will also want a tube of ultra gray for sealing the case halfs.

[cas5259]

Talked with a local machine shop about rebuilding the short block....$1200 +/- a few hundred with a 2-3 week turnaround time. The interesting thing is that they only charge $300 for the assembly, the rest being parts and some machine work. Does that sound right? That doesn't include a full gasket kit or head bolts either, which would put it at $1500. 

[montana tom]

Sounded like you are familiar with wrenches... if so you can do this yourself.  watch a few videos to gain some insight. Tear down the motor yourself,  fair chance the crank will  be ok , rods may need resizing on the big end. Apx $100 or so. have them check your crank for sizing. buy correct size bearings for it. You said motor was fine other than pressure ... if you don't want to change them, chances are your rings are fine ,allowing you to leave the pistons in the bore. Some good new head gaskets, reuse intake & exhaust gaskets , same for valve covers. I wouldn't bother replacing the head bolts , just the sealing washers on the 6 large case bolts (they seal the water system from the oil) and as stated very important to replace the case O rings.  Not all shops are truly familiar with subaru motors, if it were me I would do it myself. 

[cas5259]

Assuming the pistons (I will compression test before disassembly) and crank are fine, and all I need are bearings + maybe rod re-sizing, what should I be looking at for total cost? I wouldn't mind getting the block hot tanked just to be sure that all oil passages are clear and to save some time cleaning gasket material off the thing. Adding in a full gasket kit, is <$500 a reasonable target? 

 

One more question about foreign object debris. I will be rebuilding this over the course of a few weeks in a plain old garage and no FOD controls. Will a plastic sheet over everything suffice? Should I be worried about putting oil on parts to keep them from accumulating moisture and avoid pitting?

Edited July 26, 2016 by cas5259

[Fairtax4me]

I would oil anything that's steel because it doesn't take any time for rust to form on bare steel. One night in a somewhat moist garage and you'll have surface rust. 

If the garage is temperature controlled, may not be an issue. 

 

I would try to get the garage as clean as you can beforehand. Sweep well and vacuum to remove dust. Wipe down the walls near your workbench with tack cloth. Doesn't have to be perfect, but the cleaner you can keep your build area, the better results you'll get, especially when installing new bearings and wen putting the pistons in. 

 

No point re-using the old piston rings. If the block is going to be tanked have the cylinders deglazed or get a stone hone and do them yourself. 

 

Pistons may be fine, but you may need to replace them if the anti-wear coatings on the skirts are worn off. 

[montana tom]

Yes <$500.00 is a reasonable target, should be less. Piston rings, bearings , cam seals , subaru head gaskets . I wouldn't buy a full gasket kit just what you need ( especially the ones mentioned in my earlier post) , many can be reused. Not a lot of gasket material to clean up, hot tanking will be a luxury. Tube of ultra grey for the case.   timing belt/ components ?  have they been changed ? That would add cost. As far as keeping it clean, just follow common sense motor rebuilding 101. When you hone your cylinders, clean bores with paper towels and marvel mystery oil till the towel stays clean. Unless your humidity is so high that water drips off the ceiling, i would not worry too much. I cover everything with clean shop towels . If there is a lot of debri in the air (dust ) then cover over all with plastic. 

[cas5259]

Ok, I got the engine out this evening. All went well, except the torque converter came out with the engine, along with a bunch of ATF.  All the flex plate bolts were out too, it was just stuck or whatever. I've done a little reading about the issue, but haven't been able to make much sense of turning it and such. Won't really have to worry about it for another few weeks anyways.

 

First up was to make a rebuild bench and get some good light on it.

 

Alright, here we go

 

I found that removing the whole intake made it much easier to get at the flex plate bolts, plus it all comes off as mostly 1 piece with all the wires anyways.

 

Flex plate access

 

4 hours later and its out! My electric ratchet was clutch in getting the lower engine bolts out.

 

The whole torque converter came off, is this ok? At least it looks like the whole thing came off, compared to a few other pics I've seen. The input shaft is just 3 bare splines. ATF was dripping out of center of the TC and went everywhere except where there was cardboard already laid down.

 

Should be able to get it fully disassembled next week.

Edited August 18, 2016 by cas5259

[montana tom]

Torque converter should have stayed in the tranny, now you will need to make sure that it is seated completely before trying to reinstall your motor. Has to properly mate with the pump inside tranny. The face of torque converter (the bolt holes ) should sit just 1/4" or so in from the bellhousing. Must have room for the engine to completely bolt up tight to the bellhousing and be able to turn torque converter by hand to line up converter bolts. If it is not seated completely and you tighten the motor up ,you will ruin the front pump in tranny. I would take the time to reinsert this long before i was thinking of reinstalling the engine. Could take you a few tries. You might also consider replacing the lip seal on the tranny since you have the converter off. Standard practice is never let the converter slide off if your not removing the trans. 

Edited August 18, 2016 by montana tom