So I took the car out yesterday and got an alignment, and took it on a long drive about 1 hr. to a pick n pull, then an hour home. After I got home, I noticed that there was smoke coming from under the hood. I lifted the hood, and it looked like it was coming from under the intake manifold? 

I did change the plugs and coil, and the drivers side valve cover gasket,and the oil. The car sat for about 6 months before I got it. 

Anything I should check? or is this just from sitting?

did it smell like toasted marshmallows or like oil?

 

any fluids low?

 

any chance the smoke was drifting up from lower dow, near the exhaust?

oil pressure sending unit is a common oil leak on top of the block. I would look there first. This yoube video shows you where its at-

this video better to locate oil pressure sending unit

 

First it's been driven far for 6 months?

 

Common stuff I've seen is the seperator plate leak dripping on the exhaust and coming up behind the motor (could look like from the intake manifold)

 

cracked CV throws grease on the exhaust and does the same.

 

sometimes you can get power steering/coolant leaks up there but I don't know that they would smoke. I'd take a flashlight and chase it down some more. Make sure your fluids are topped off. As mentioned - the smell can tell you a lot.

I will look at the sending unit. The smoke did not last long and was hard to tell where it was coming from, but appeared to be under the intake. 

Yes it is the first time the car has been driven much in over 6 months, it is new to me, and the last work the PO had done was over 6 months ago, as per the receipt. And it has sat since then.

 

All fluids are ok, but I did just change the oil, coolant is still full as well as the PS.

 

As this is my first Subaru, what is a separator plate? 

Hi,

Back of engine...so not an easy fix: 

Really need to know what it smelled like. Coolant has a very unique, sweet odor and if you have a pinhole in a hose (radiator hoses, heater hoses, etc.), it'll spray once the hose is hot enough (system pressure increases, hose gets hot and expands, then it sprays), and will appear like it's smoking. Once temps drop in the hose, it can seal the pinhole leak, making it more difficult to locate.

 

Oil or even grease getting burnt either directly or from radiant heat is also very distinctive but noxious and unpleasant. Think the most repulsive car-related odor in my opinion is a diesel that's burning oil (utterly disgusting, foul odor).

 

If it's coolant, you can leave the radiator cap loose (engine cold, loosen cap slightly) and at least drive the car until you get it fixed, but don't go long distances and always watch the engine temp gauge. This more of a "get it home" trick that works by preventing the system from pressurizing, hence the hole will stay sealed.