Every job starts out just fine. Then, after a few minutes the item starts to look like this


Next thing I know, the cold end looks like this:


The nozzle is always clean, so I think I'm getting heat crawling up into the top block.

I bought my Maker Select last Black Friday. At the same time, I bought a 1 kg roll of 1.75mm white PLA. That entire roll worked flawlessly.

When the white ran out, I encountered my first jam. The extruder didn't have any more filament to push, so the top block just melted the filament into a blob.

I bought a 1 kg roll of silver online from a different vendor. I couldn't get anything to print correctly with the silver; I returned that roll - assuming it was the PLA, because my white always worked.

I then went back to Monoprice and bought a 1 kg roll of blue to get back to the same brand of PLA. I also bought the "cleaning" filament to make sure everything was clean. I ran the cleaning filament through to clean-out the silver mess I had made.

I've had nothing but trouble with this blue, too. I've tried several different extruder temps - as high as 215. I got the bright idea of trying to print with one of the GCODE files that was on the sd card that came with the printer. That yielded the above photos. They all seem to work for 5-10 minutes, then the jam happens.

Each time I get a jam, I end up in the garage with the propane torch. The PLA is so jammed that I can't push it through with any tools. I have to take apart everything!

I am at a loss. Why would that white work so well and the silver and blue be so much trouble? I have so many ideas, but my love for 3D printing is quickly fading

I have my spool-holder sitting on top of the unit. Sometimes the spool will get kinda "tight" before the extruder pulls the filament and unrolls a few more inches of filament. Could the problem be my spool holder or the gear that pushes the filament?

I read a bit about lubricating the PTFE tube and its path. Should I try some light oil, or will I just encounter yet another failure?

Plus, one of the many times I had to disassemble the stupid head, I managed to stick a hex wrench into the cooling fan. I broke two blades off that fan - on opposite sides, so I didn't mess-up the balance. Could I have compromised the cooling ability enough for that top block that I caused my own jams?