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Oil Consumption or a leak? Help Please!

55K views 105 replies 21 participants last post by  effsweet  
#1 ·
I am trying to figure out two things:

1.) What (if anything) seems to be leaking or building up here:

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On this one, notice the tiny drop of oil? on the plastic underguard..
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As you can see, the connector/plug in the center of the photo seems to be collecting a lot of grime of some sort. Does anyone know what the components in this area are and what they do? To give you a point of reference, you are looking at the driver side front of the engine block, between the oil dip stick and filler tube. I am worried there might be an oil leak here, which leads me to my second question...

2.) I seem to be burning or losing more oil recently. I did my last oil change at 67,300 miles and used Mobil 1 0w40 European Car Formula because it was on sale and if its required by Mercedes and BMW, it must be good enough for a Subaru! I know Subaru recommends 5w30, but I have used the 0w40 before (in the winter) without issue. At about 72,000 miles I had to add a quart and a half of oil because it was well below the lower mark on the dip stick! Shame on me for letting it get this low before noticing, I am usually VERY good about checking the level regularly!

So I am wondering, am I leaking oil from the aforementioned area of the engine, or am I just burning it because of the different weight/viscosity? Once I get a dry day here, I am going to change it out for 5w30 and see what happens...

Thanks!
 
#4 ·
I do the oil changes and did not spill a drop. Just cleaned the engine not too long ago, but I will wipe off that area and keep an eye on it.

Can anyone describe the parts in that area?
 
#5 ·
Are you possibly missing the rubber O-ring seal on the oil filler cap?

I believe the sensor with the black connector is the oil "pressure" sensor, so its possible that could be seeping a bit. Or it could be something around the cams, possibly the cam seals on that side are leaking?

It does look like a bit of an oil mist is spraying out from somewhere near there.
 
#7 ·
Good thought about the filler cap o-ring, it ALWAYS comes off the cap and sticks to the filler tube when I remove it. I have to re-seat in into the cap every time, so I know its there.

I am curious about this oil pressure sensor theory... I am going to play with it tomorrow and see if it's removable and if there is any sort of o-ring that may have failed. Anyone else have any input on these sensors? I wonder what the blue one is...

Just got some Mobil 1 5w30 today. Will change out the oil later this week.
 
#6 ·
What a lovely clean engine, I'd eat my dinner off that:biggrin: One tiny drop of oil could very well be a drip that ran down the outside of the filler tube but as Flst.. said, clean it off and watch. From looking around this site it seems Foresters do burn oil, mine has 130K miles and does about 1400 miles on a litre, which is odd for a healthy engine because any car I had in the past that burned oil was in trouble. I've not heard the Impreza boys over here commenting on it though. A drip that size from a leak would not account for the amount of oil you had to replace either.
 
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#10 ·
I would take off the part of the timing belt cover in that area (pretty easy to do) and check for any oil residue inside the cover and around the cam sprocket. That should help isolate where it is coming from.
 
#11 ·
I changed my oil last week and used regular old Mobil 1 5w30 this time. I also cleaned the suspect area really well so that I could keep a better eye on it. After the weekend and about 100 miles, this is what it looked like.....again....

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^You can actually SEE the oil pooling up in an indentation behind the oil pressure sensor!

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^Another angle to show that it's leaking from all around that oil pressure sensor connection. What's up with the threaded hole next to the sensor? Is something supposed to be screwed into that?

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^A shot from above, looking down on the pool of oil and mysterious threaded hole...

I made an appointment at the dealership to get this looked at under warranty later this week. Hopefully it will be a simple fix. Thanks for your help everyone!

PS: Is it appropriate to ask if I can go back with my car and watch the mechanic work on it? I don't want to upset anyone, but I do like to be as involved as possible...
 
#12 ·
Not really, though I understand where you are coming from. Most of the time, shop's insurance won't cover you being back there, and honestly, if I were working on someone's car I wouldn't want them staring at my hands the whole time either.

Stan
 
#14 ·
I thought about doing that...but I figured since it still has a drive train warranty I would have the dealership look at it and make sure it's not something more serious...or that is going to happen again.

I might play around with it tomorrow. I am probably going to have to remove the battery and oil filler tube (if possible) to get better access. I don't have a set of open-ended wrenches and it's going to be tight with my crescent wrench! Maybe I could use a deepsocket if I manage to unplug the wiring harness...
 
#16 ·
Well, it turns out my warranty is expired...so I will be replacing the oil pressure sensor myself! The part was only $21, and I will pick it up on Saturday. I will take some pictures and do a how-to for it since there doesn't seem to be one yet.

Has anyone done this before? I am going into it completely blind!

Thanks.
 
#17 ·
I was just looking back at the receipt and realized they ordered the wrong part...I think... They ordered the "oil pressure switch" PN: 25240KA040. I was doing some searches and found a picture, and it looks nothing like the so-called "oil pressure SENSOR" that is leaking on my car. Does anyone have the correct part number? I would really appreciate some help!
 
#18 ·
I think I got it sorted out now. Just got off the phone with the parts guy and we think its the Oil Pressure Switch for the HEAD LOCATION that I need (PN: 25240AA060). Apparently there are two different "oil pressure switches", one for the block (under the alternator), and one for the head (next to the camshaft position sensor). Glad I caught that one early on!

I think I am having the same problem as "muchomas" HERE.

I don't think it will be too hard to replace. Does anyone have the torque specs?
 
#19 ·
I did some recon this afternoon to try and figure out how to replace the sensor once I get the part.

Here is a high level view of the area:
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Here is a close-up with labels that I am not 100% sure about...
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It looks like I am going to need a ~23mm deep socket to get the sensor out. The area is too tight to use a crescent wrench, even with the oil filler tube removed. Can anyone confirm that socket size? I had to guess...
 
#21 ·
...18 ft lbs with a GOOD torque wrench. Unfortunately I have a Great Neck P.O.S and I just cracked the head when I was only at "10 ft lbs"!!!!

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With the oil pressure switch re-installed...

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I feel like I am about to puke right now I am so pissed. :icon_mad:

How bad is this? I revved the engine to 2k-3k rpm for about a minute and it had already leaked from the the crack and dripped onto the under cover.

How big is the larger engine component that this is part of? I am afraid I will have to replace the entire cylinder head...

Maybe I can just get creative with some JB weld?

Sad day :shake:
 
#23 ·
That mounting boss for the oil pressure switch is part of the cylinder head.

Options:

1. Replace the cylinder head.

2. Do a poor mans fix. A metals grade epoxy(google it for many options), pick one with oil, fuel and heat resistant properties. Personal note I wouldn't do it on my own but done right it WILL work.

3. Find some one to weld it and rethread or retap it as needed. A good welder(tig would be my preferred) can grind a V notch along the crack, thread a steel plug into the hole, weld it and remove the steel plug. That should leave you with a good hole to thread a sensor into. Add some liquid pipe dope to the threads before installing.

Doing #3 on the vehicle would be my choice but it will require you to do some disassembly to get the room for the welder to do their work. One could also pull the head and do the reapair.

Your only inexpensive option is to epoxy it. A new head is over $400, a used head should be ~$200 and labor will be that of about head gaskets. Shop rate for just a weld repair should be less then $100(I would expect <$50 in my area), disassembly to get to clearance to do the weld depends on who is doing it and how much room the welder wants.
 
#24 ·
I think I am going to try the epoxy weld first. Then, when it comes time to replace my head gaskets and timing belt I will either replace the cylinder head or get it TIG welded. I would think the engine oil needs to be completely drained before you can put a welder anywhere near it, and it would probably be better to pull the engine and do it then.

Does anyone know how hot that area gets?
 
#25 ·
The thing to keep in mind with the epoxy is that it is not easily cleaned out from the crack which can make it a pain to try and weld later. The oil can be cleaned out with a evaporating chemical degreaser, the epoxy is a solid that would need to be dug out with a pick.

No need to drain the oil before welding. I would rate the explosion/fire risk from welding in that area at less then a 1 on a 1-10 danger scale.
 
#26 ·
Good point. I am going take it to a renowned TIG welder on Monday and see what he can do. Is it bad if some non-chlorinated brake cleaner drips down into the head cylinder? I just need to know if I should plug the hole before I start prepping it for the welding.
 
#29 ·
Very possible....or maybe it was weakened for some reason. When I removed the original oil pressure switch it had a lot of gunk on one particular side of the threads. Maybe the crack originated on the threaded side of the boss? I wonder what my chances are in getting great neck to foot the bill for a cylinder head replacement? That sh**ty torque wrench was only showing 10 ft lbs when I heard and felt the crack...
 
#32 ·
Yeah, you're right about the crack not being there before...I'm just trying to make myself feel better about it. I was using a Great Neck needle/gauge style wrench. I think it goes from 0 to 120. I will post a picture of the exact configuration i was using in a bit. I had an extension and some converters on it.
 
#33 ·
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The torque wrench is 1/2 inch drive. I had to covert to 3/8 to use the extension, then back to 1/2 inch for the 24mm socket. This shouldn't affect the torque reading i was very careful ablout keeping everything lined up.

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#34 ·
Nothing wrong with the set up other then the choice of wrench, 0-150ftlbs.

I would of used a torque wrench with a much smaller scale, likely a 0-250 inch pound.

18ft-lbs = 216in-lbs

None of that means that it was the wrench or wrench choice is/was at fault. The end result is there is a crack that needs to be fixed.
 
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