my dads snow blower began to leak oil and i dont know where exactly, and dont know how to check it.. Its a toro 826 LE power max. Im not sure of the engine size and all that because we seem to have lost the owners manual. I know that engine is made by tecumseh. I do know that we havent changed the oil since we have bought the snowblower about 3 years. We keep it stored in the garage which is very very cold. We used the stock oil that came with the snowblower. and my dad just added 10w30 lawn mower oil in it. I wanted to give it a tune-up...so what is it that i need to do..and what might cause the oil leak..

Thank You for any help

Your Toro is model is 826 so thats 8hp 26" :) An oil leak is pretty vague, there are alot of places oil can come from. The most common places on tecumseh engines are the crankcase cover and back crankshaft seal. I have the same engine on my MTD and I just replaced the crankcase gasket and its about 5 years old now.
You shouldn't be using 10w30 in a snowblower, you need the oil to be thinner on startup so you should use 5w30. Find out where your oil is coming from, good luck !

Not to take away from Justin, but I'd check the easy things first:
Is it leaking while sitting, or while running?
If while running, check for overfilled oil, and/or a loose dipstick tube. Either will cause it to pump oil out of the breather near the carburetor. Overspeeding will do this too.
If while sitting, can be: side cover gasket; drain plug issue or cracked around plug/adapter pipe; or poruous block/side cover.
Like Justin says - you have to determine where it's coming from in order to address it.

I would change that oil,3 years in a snowblower it's time.
Like Justin says 5W20 or even straight 10W then check for your leak.

i was reading on other post that i can put 5w30 mobile. are they talking about the car motor oil. I bought a quart but my dad doesnt think i can put it in. i have not tested it to see where it is leaking from..and i also wouldnt know that name of the places it does leak from. is there a diagram of what the engine looks like and the names of the parts so i can accurately inform you guys with correct description.

5W30 oil , can be any brand , Penns oil.Quaker State or the like.

alright. so central ma is planning on having 6-10 inches of snow tomorrow. and with the whole snowblower leaking oil i was planning on giving the snowblower a tune-up. I just wanted to know what does a tune-up consist of for my snowblower. i know the oil has to be changed, is there anything else? good description is greatly appreciated. thanks

Snowblower tune-up (vs. a service, which is more involved).
Top-up oil first.
Test-run to see how engine performs.
Check/change spark plug (once it cools)
Check pull-starter rope for fraying - Tecumseh's fray about 1" down from the grip
Change oil (you may want to use 0W-30 instead of 5W-30 if air temps been around 0 deg.)
Check/replace belts as nec. / adjust belt clutches/idler pulleys as nec. (pull the belt cover to inspect for belt cracks etc.)
Adj. tire pressure - usually 20lbs is fine
Check/replace skid shoes and scraper, adjust skids (must do tire press. first)
Note: some older Toro's used a spring-loaded scraper - you need a little pre-load on it when you set the skids, so it cleans the pavement well
Older units only: top up 90w lube in auger gear box
Check/replace auger shear pins
Grease auger rakes if equipped with zerks
Spray-lube auger shaft bushings at outboard ends
Spray-lube all controls, chute pivot and rotation gear
Tighten handlebars if loose (often on older Toro's)
Check self-propel clutch / condition - run unit, should spin tires if held back on dry pavement in 1st or 2nd "gear"
Check headlight if so equipped (yuk yuk)
That's about it...
Be sure to use Sta-Bil or other fuel preservative in the Spring - even a good idea now in case it doesn't snow. Best to just add it to your storage can when you buy fuel.

so add sta-bil to storage can? we are still getting snow here so should i just do that now? or wait til spring

It comes down to: when do you think you'll use it last? In Mass. I can understand waiting, but here in N.J. our winters are, well, unpredictable.
I guess I'd wait and add it in March...
Paul