Replace the front O2 sensor even though there is no code. use a direct fit sensor only, no universal sensors.

Oxygen sensor after the catalytic converter, and connected to cylinder one exhaust.

I want to know the code number please, not what the code reader referred to it as. Was that the only code?

There is an air vent plug on the radiator to bleed the air out. Did you loosen this and bleed out air after filling the cooling system? If you did and that is all good then you have to do what is called a cooling system combustion gas check. You can buy this inexpensive tool or rent it for free from a large chain auto parts store by just leaving a deposit. You may have to pay for the liquid chemical that it uses. I suspect you have a blown head gasket.

Yes it could but if that were the case then your car would have no power, it would be noticeably difficult to get the car up to speed. If your power is there then it is not the cat. Anything that causes you to overheat and lose your heater is related to the engine. This reeks of bad head gasket. If you start the engine cold, put your hand on the radiator hoses and if they become noticeably under pressure in just a few minutes then it more says bad head gasket.

Check these websites for the repair manual; www.diyrepairmanual.com, www.manualspace.com. You can also try the local library and any local auto parts stores for the manuals / diagram.

Plug in a code reader and see what codes might be set.

i have the same exact problem..please let me know if you have found out the solution

Hello
Hopefully the gasket did not move out of position when you re installed the valve cover. These engines are notorious for head gasket leaks and rear crank seal leaks . Make sure those are not your source of oil loss before you go too much further.
Hope this helps
Joe Boulay
Automotive Technician & Author
joe@joeboulay.com
www.joeboulay.com

Things like this can be very hard to find untill it happens more . I'm sure your dealer told you the same thing . Sorry but you might have to keep driving it untill it acts up enough for someone else to hear it .

This could be a few things. From experience, I can tell you that my roof rack will make a hum at highway speeds if there is an extremely strong crosswind that hits the crossbars just right. The moment I realize that the rack is making noise it seems to go away - this is probably because I slow down to see if I can hear the noise better, but this changes the wind speed across the rails, and therefore stops the noise. Also - some of these vehicles had an issue with rear wheel bearings making some noise at highway speeds after they've gone about 50,000 miles - defective bearings?. The dealer should be well aware of this as well, and there should be a Subaru Tech Bulletin about it floating around out there - the wheel bearings are covered under an extended warranty (I do not have the specifics regarding the mileage or age limitations on that warranty). If your dealer doesn't know about this, then I suggest speaking to a Subaru Regional Director or Manager, or, if feasible, see if another local dealer can assist (if there is another one in your area). Good luck… Just because the service tech can't duplicate the noise doesn't mean there is no problem. Don't take no for an answer if it's really bothering you.

This could be a few things. From experience, I can tell you that my roof rack will make a hum at highway speeds if there is an extremely strong crosswind that hits the crossbars just right. The moment I realize that the rack is making noise it seems to go away - this is probably because I slow down to see if I can hear the noise better, but this changes the wind speed across the rails, and therefore stops the noise. Also - some of these vehicles had an issue with rear wheel bearings making some noise at highway speeds after they've gone about 50,000 miles - defective bearings?. The dealer should be well aware of this as well, and there should be a Subaru Tech Bulletin about it floating around out there - the wheel bearings are covered under an extended warranty (I do not have the specifics regarding the mileage or age limitations on that warranty). If your dealer doesn't know about this, then I suggest speaking to a Subaru Regional Director or Manager, or, if feasible, see if another local dealer can assist (if there is another one in your area). Good luck… Just because the service tech can't duplicate the noise doesn't mean there is no problem. Don't take no for an answer if it's really bothering you.

Sorry - posted twice in error. The TSB is # 246863 - The dealer should be able to look this # up and review the Tech Service Bulletin and remedy.

Its not a wheel bearing because the noise from a bad wheel bearing, although it does sound like a siren, it will not go away after a few minutes. I think you have a loose heat shield (broken / rusted through retainers or welds) that is vibrating and giving off a harmonic sound because they are like pieces of tin. When the exhaust system reaches full temperature the high frequency vibration is dampened. I would lay under the car and use the side of your fist and smack upwards in different places of the exhaust system and try to "hear" the noise. Do it when the car has not been started up yet for the day, ice cold.

most cars have a vent on the ank either to atmosphere or to (thanks to al gore) a vapor canister under the hood, you may have a blockage in this

Gas pumps work off of vapor pressure when there is little to no vapors they pump fine, this is when the extra vapors funnel out the vent
however they shut off when the vapors stop venting
like when the fuel reaches the top of the tank, or in your case some thing is blocking the flow of vapors

Usually, the oil patch is due to the PCV system and small filter located inside the air cleaner box - being saturated with oil. Simply replace the small PCV breather filter foam piece (usually less than $2.00) with a new one.