Help diagnosing Subaru

[ispoonwithmugen]

So a little backstory here. A few weeks ago my girlfriend bought a 2005 Subaru Forester LL bean edition. Good deal and it seemed to be in good condition. There were a few yellow flags but not red flags and for sub $5,000 you can't expect TOO much.
Timeline:

We drive the car the 60 miles home without issue.
8 days later it starts stalling while driving
Check CEL it's for P0302 (Cylinder 2 misfire)
Change the spark plugs and clear code and it goes away
Car won't start half of the time and then it will fire up normal the other half of the time
Get new CEL for 02 under threshold and I'm on a 60 hour work week for the next few months so said okay let's just take it to a good shop around here. They diagnose it by saying it's the rear 02 sensor. Okay sweet. Change that and it runs even shittier (the dealer had also put in a new cat before we bought it).
Still runs like shit but now worse. Sometimes it'll run fine but others it is almost stalling while driving. Lillie couldn't get it above 35mph and if stopped would stall.
Pull new codes for 2 cylinders misfiring now (keep in mind this is less than a fricken' month into ownership!!!!). Tell her to take it back to the shop to rediagnose it since that 02 obviously wasn't the issue. They come back and say that it is a head gasket (great can't wait for that to compound onto my already week). I'm still not certain I agree with the diagnosis.

Is there anything else I should check/change before pulling this motor apart? These motors (2.5 Subaru N/A) are known for their HG issues but I'm not seeing any mix. We get it back from the shop today so I'll check again but didn't see anything.

[Senor_Taylor]

O2 readings being off can easily be the Air Fuel Sensor (upstream O2) and not the rear. Those seem to fail more often in general.

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[SlimKlim]

I'd want to see a pressure test with my own eyeballs to make sure it's the HG. Do you smell coolant after driving? It could theoretically be leaking to the outside and losing compression but not mixing with the oil.

[BLINGMW]

I'd want to see a pressure test with my own eyeballs to make sure it's the HG.

Me too. I would say it's pretty easy to do... but on a Subaru I have no idea, doesn't look easy.

FWIW it doesn't have to be mixing fluids to have a head gasket leak. We just did the HG on my dad's '05 outback, coolant was clean, didn't lose any coolant, ran great. It was just leaking oil. Now it's not. But I DO doubt the diagnosis unless your HG is just destroyed. It would have to be pretty super bad to prevent the car from starting.

How about engine grounds? Vacuum leaks? Seafoam it! Let's verify some easier stuff first.

[.RJ]

Sounds like a head gasket.

Pro tip: faster to pull the motor to change them

[CaptainHenreh]

These motors (2.5 Subaru N/A) are known for their HG issues but I'm not seeing any mix. We get it back from the shop today so I'll check again but didn't see anything.

It's the headgasket.

[JPolen01]

These motors (2.5 Subaru N/A) are known for their HG issues but I'm not seeing any mix. We get it back from the shop today so I'll check again but didn't see anything.

It's the headgasket.

There was no reason to read anything else.

[ispoonwithmugen]

Well they showed me compression tests and leakdowns. Appears to indeed be the HG. Stupid Subaru. Should've known not to trust the N/A motor. Any advice for removing or tutorials online are appreciated. Looks like my little freetime will be spent yanking the HG on this stupid thing. Don't think I have enough space to pull full motor so I'll figure out how to do it without removing motor.

[davej]

was this a private sale or a small dealer? Maybe you're still on some kind of tail light guarantee?

[ispoonwithmugen]

Dealer. They're willing to work with us at a 50% rate but that's still $500-$1000 that we don't have unfortunately. Sold as-is with no warranty expressed nor implied.

[ScottyB]

ah damn....i was feeling really good it wasn't the HG but if your compression is showing up weak then i guess that would be it. sorry dude. any N/A on stock head gaskets is a goner, just a matter of time.

whatever you do, absolutely confirm that they're going to put in the Multi-Layer Steel gaskets from the turbo cars. if they put a single layer gasket back into it, you'll have the same problem all over again.

what is the mileage? this is when everyone does t-belt service on a subaru (every 100k miles), and if you do the t-belt you want to absolutely replace all the pulleys too. you can do it with the engine in, its just harder.

for coolant, replace it with straight up Peak Global in the gold bottle. DO NOT put the subaru head gasket sealer goop back in, its just a bandaid for the shitty OEM gaskets and eventually clogs up the heater and radiator core.

this video is an excellent guide and is the same engine you have. there are a ton of DIY's on youtube for this unfortunately (or fortunately in your case)
[youtube]yakX-GAV9uE[/youtube]

this is another excellent guide for a DOHC but the tools and processes are the same.
[youtube]6mjCegTnB60[/youtube]

wish i could come help buddy

or, alternatively, dump some more subaru head gasket sealer goop in there, drive it to carmax, and dip out of there with your money back.....

[D_Eclipse9916]

Yup, also call MachV


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[ispoonwithmugen]

In California meow. No more Mach V

[Senor_Taylor]

I'm with Scotty on the CarMax thing, kinda.

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[JPolen01]

3rd vote for carmax. Dump that thing.

[ispoonwithmugen]

Hm. So the only thing is that this car was bought from Carmax by the dealer that sold it to us. Not sure if they'll buy back the same car again but I'll take it there and try I suppose.

[CaptainHenreh]

Hm. So the only thing is that this car was bought from Carmax by the dealer that sold it to us. Not sure if they'll buy back the same car again but I'll take it there and try I suppose.

Find a mechanic, get the gaskets replaced, c'mon man. If me and my dad can do it in a weekend you can find some Cali shadetree fuckhead to do it.

[ispoonwithmugen]

^ lol we talked about it and I'm just going to replace it and probably the timing belt while I'm in there.

[JustinG]

[ispoonwithmugen]

^ My feelings. Unfortunately Carmax wouldn't buy it for squat. Soooo the dealer told us they'd work with us and make things right. Now they told us to eff off. Worst experience I've ever had with human beings. Anyway, after the thoughts of lighting their building on fire with them inside subsided on the train ride home I decided I'll just suck it up and get this over with. Spent 5 hours tonight taking some of the stuff out of my garage and prepping it. Got the alternator, belts, battery, intake and vacuum lines up and out of the way.

Now I need to go buy a drain pain for the oil and coolant (and probably some mixture of it). I've been following a tutorial on YT that's been pretty handy. Do you all have any other resources (other than the obvious) that you used? I'm going to try to do this without pulling the motor so we'll see how that goes. Has anyone else done it that way?

As far as parts. What all did you (the people that have done this) get? Did you buy new head studs? Did you go with an STI HG versus the faulty N/A one? Is there anything special I need to do for that?

I don't think we're looking for long term reliability here so trying to keep this as low as possible. Probably short term (1-2 years max) and flip it for hopefully some sort of profit.