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2003 Subaru Outback Limited
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Discussion Starter #1
I have the dreaded P0420 code.
I cleared it a week ago, but it's back.
I'm about to try replacing the PCV valve, but have a question.
Amazon have several they claim are genuine Subaru with many difference part numbers...11810AA000...AA021...AA120...AA130
This seems to be the first path on a long chain if discovery on this code.
Does anyone know what the correct part number is ?
 

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'14 Subi OBW, '18 Subi Forester
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A virtual neighbor!

I went thru the 'which PCV valve' for an '02 EJ25 game years back. Probably have two that I bought somewhere, and neither fit. I finally just pulled mine and cleaned it well with a combo of carb spray and WD-40. When it was totally clean and rattled easily, I just put it back in.

The connection to your P0420 isn't an obvious one (at least to me). Typically the problems associated with a bad PCV valve is that you end up with a mildly pressurized crankcase rather than one below atmosphere, and you push oil out from your valve cover gaskets or spark plug tubes.
 

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2001 VDC/SC One of a Kind
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2003 Subaru Outback Limited
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36 Posts
Discussion Starter #4
Have you looked here: http://www.subaruoutback.org/forums/66-problems-maintenance/49537-p0420-diag.html

How many miles on the car and what maintenance has been done in the last 50k?

How many miles did you drive in that week?

Do you pay attention to the temperature gauge? When was the last time you changed the thermostat and flushed the coolant?

What brand of gasoline do you use?
I've had the car a month.
It's done 189k
The dealer did head gaskets, timing belt and alternator before I bought it from him.
I drive on average 15/20 miles per day 5 times a week.
I normally use regular gas, but put a full tank of premium in as the last fillup. It's Shell.
I do keep a close eye on the temperature gauge. It's always midway. It never moves. I have not changed either the thermostat or flushed the coolant recently.
My local Subaru dealer has a complimentary offer of a free inspection. I'm thinking of taking them up on it, just to put my mind at rest and to get some idea of the work needed on the car.
I recently took the car to have the oil topped up, as it was down couple of quarts...I'm trying to keep an eye on it, as I smell burning oil from time to time when I've finished my journey, or I've got it up to 60...
 

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'14 Subi OBW, '18 Subi Forester
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Given that you only have a 4.2 quart crankcase (IIRC), being "down a couple of quarts" means you were really flirting with disaster. Keep an eye on this going forward.

How soon after purchasing the car did the code first appear? Did the car pass the NYS Emissions test (get a valid window sticker)? Assuming it did earn a sticker, the cat was in passing condition last month. It failed, you cleared the code, but it came back in a week (but not immediately). Did you clear it with an OBD tool, or by wiping out everything with a battery reset? Any warranty from the selling dealer?
 

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2003 Subaru Outback Limited
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Discussion Starter #6
Given that you only have a 4.2 quart crankcase (IIRC), being "down a couple of quarts" means you were really flirting with disaster. Keep an eye on this going forward.

How soon after purchasing the car did the code first appear? Did the car pass the NYS Emissions test (get a valid window sticker)? Assuming it did earn a sticker, the cat was in passing condition last month. It failed, you cleared the code, but it came back in a week (but not immediately). Did you clear it with an OBD tool, or by wiping out everything with a battery reset? Any warranty from the selling dealer?
I first came up about 3 weeks after buying the car. It has driven around 400 miles before it came up.
It passed the emissions test the day I bought it. When the code first came up, I cleared it with an OBD tool, but I've a feeling everything is going to disappear again today as I just installed a new stereo and had to disconnect the battery.

As you are also in Dutchess, can you suggest anywhere I can go to request them to check the O2 sensors ? I dont really want to go anywhere near replacing the CATs
 

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Unfortunately it's not exactly around the corner from you, but Automotive Technology on Rt 55 in Lagrangeville has a good reputation with Subaru vehicles. The owner (Greg, IIRC - haven't spoken with him in many years) is a former SOA District Level tech - one of those guys they'd send out to tackle difficult cases.

Correction: George Holtzberger is the owner / head guy. If you decide to go there, let us know the outcome?
 

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Discussion Starter #8
Unfortunately it's not exactly around the corner from you, but Automotive Technology on Rt 55 in Lagrangeville has a good reputation with Subaru vehicles. The owner (Greg, IIRC - haven't spoken with him in many years) is a former SOA District Level tech - one of those guys they'd send out to tackle difficult cases.

Correction: George Holtzberger is the owner / head guy. If you decide to go there, let us know the outcome?
The light has remained off since my battery was dosconnected. I will let you know if/when it comes back.
I'm started to think it may well be the Cats, as I'm getting a faint bad egg smell VERY occasionally....
I'm also thinking the burning oil smell after driving a while could be this.

When my 01 started leaking at the valve covers you would get the faint burning rubber smell as the oil burnt off. If your getting some of that then you probably do have a seal or gasket some place thats failing. The most common spot for this is behind the timing belt cover the oil pump is seated with an oring seal. Generally when they do the timing belt they inspect this and replace the ring if its showing any signs of leaking. It's possible they missed it and thats starting to leak. You wouldn't really notice it given it sits behind the plastic cover on the front of the engine lower driver side corner. If its dirty under there you could clean it up and then keep an eye on it and see if any oil build up is showing up.


They replaced the timing belt when I bought the car. Maybe they missed this seal ?
 

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The rotten egg smell is typically hydrogen sulfide formation. It doesn't necessarily mean the cat itself is bad, as poor quality fuel or the engine oil (that you may be burning) could contain some sulfur.

On engine oil use - My OBW recently started giving me a 'burned oil' smell that I initially thought was a center clutch issue until I saw a few black, charred tar-like drips on the garage floor. I think it's dripping onto the steering box and down onto the exhaust heat shield. Just something new to investigate...
 

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Discussion Starter #12
...and I've no obvious oil leak as far as I can see. I put paper underneath the car when I got home, and there's absolutely nothing on it.
 

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...and I've no obvious oil leak as far as I can see. I put paper underneath the car when I got home, and there's absolutely nothing on it.
If yours still has the shield underneath, you most likely won't see oil leaks on the ground.

I'd suggest running your fingers around the bottom of the head gaskets and valve covers when the engine is cold.
 

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I wish I had taken pictures. I had the dreaded oil smell on my '01 OBW auto and assumed it a rear main oil seal. It turned out to be the oil separator plate in the rear of the engine.

JP
 

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Discussion Starter #15
If yours still has the shield underneath, you most likely won't see oil leaks on the ground.

I'd suggest running your fingers around the bottom of the head gaskets and valve covers when the engine is cold.
Not an expert at all this. Where would the head gaskets be ? Are they on either side of trhe engine, at the end of the intake manifolds ( I only know this cos I'm looking at haynes)
 

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Discussion Starter #16
OK, it now looks like I'm definitely losing oil somewhere. I've gone from full to almost at the low line within 3/4 weeks.

I sort of had a fear this car could become a money trap. The dealer is now not answering any calls about the previous work it's had done.
 

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OK, it now looks like I'm definitely losing oil somewhere. I've gone from full to almost at the low line within 3/4 weeks.

I sort of had a fear this car could become a money trap. The dealer is now not answering any calls about the previous work it's had done.
If the work was done at a Subaru dealer, I believe they are all "connected"...just call another and all they need is the last few digits of the VIN then they can give you a synopsis of any maintenance done through SOA...
 

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Would a bad PCV valve cause the check engine light to be on? Mine isn't on, but oil is leaking from somewhere. I have been told it could be the oil separator plate (one mechanic my dad knows - retired from Subaru) and he said my head gaskets were fine. Then another friend of my dads (who has had three of these) said his did this and it was his valve cover gaskets. Now my car is overfull on oil (and does not seem to lose any oil level), whoever changed it last filled it to the notch above full and I think it is there whether the car is hot or cold. Then I heard that a bad PVC valve could cause oil pressure to push it out. Anyway after coming up my hill, when I turn off the car, it will smoke from under the hood for about 30 seconds. Does not seem to do it when I turn off the car in town when parking on a level lot.

At this point, not sure what it is - PVC valve, oil plate, valve cover gaskets? I am going to try to get a 2nd opinion at a Subaru shop on Friday afternoon.

How do you check / change the PCV valve on these? Mine is a 2000 Outback 4-cylinder wagon.

Thanks!
 
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