Product review (5 stars): Quick and Inexpensive Fix
Solved my dryer's no heat problem.  The dryer would make a rattling noise for about 60 seconds every few minutes as it tried to light the burner but to no avail.  It took about 30 minutes to disassemble, install, and reassemble the dryer.  Unless you remove the drum completely, I recommend using a 90 degree or ratcheting screwdriver on the screws that hold the coils in place as they're hard to access on my Whirlpool dryer.