83 300CD
Hit -10F last night, it's only 6F now. The car started yesterday at 5F with a little patience but won't start today. I've just plugged in the block heater, don't know if it works. Charging the batt to to help warm it up a little. Are the any other SAFE things to try to get it running? Is spray start dangerous with a diesel, i.e. do I risk blowing the head gasket? Should I just kick back for an hour and let the heater do its thing? I'm thinking the hood pad insulates this motor so well, it still thinks its -10. The hood pad looks nice but the snow never melts!

Thanks