Help with my Kenmore Sewing Machine Mdl 158-12310?

Check the manual to be sure you are threading though all the correct guides.

Lift the presser foot and pull the thread through to the needle.

Adjust the tension to a setting between 3 & 4.

Check the manual again, to be sure the needle is inserted properly and when you thread the needle, make sure not to thread from the back of the needle.

Threading diagram - http://www.sewusa.com/Threading_Diagrams/Threading...

Do you have the manual? Snapping threads are typically caused by:

--misthreading

--bad needle

--too heavy an upper tension (something around 4 is normal)

--snags on the thread path

-- bad thread

Time for some detective work. I'd start with a new needle, upper tension at 4 and a new spool of decent quality thread like Gutermann, Mettler, Madiera, Superior...

It's always a good idea to clean the machine (brush and vacuum, not compressed air) and oil (sewing machine oil only, not 3 in 1 or WD40 type oils) per the instruction manual before you start troubleshooting.

Too big of thread in to small of a needle.

Too much tension (probably on top)

Maybe the needle plate hole that the needle goes through is beat up and the thread is catching on it.

Maybe the thread is as old as the machine.

I can almost guarantee it is threaded incorrectly. From the back, through the guide, over to the front, down, then up then down, then thread the needle. Make sure every place it is supposed to catch it does. I totally agree with the comment about cheap thread. If it is less than a buck it is probably junky.

Make sure it is threaded correctly, including the needle.

http://www.sewusa.com/Threading_Diagrams/Threading...

Use good thread and not those that are sold 3 for a buck.

How do I remove the cover?