I start mine about 5 minutes before we leave the house. Having a toddler to drop off at school forces me to at least get some heat inside the vehicle before sticking a child in the back seat.

Also, I have heard nightmare stories about CCV's failing from condensation freezing from short drives. Wouldn't warming the engine for a bit help to eliminate some of this?

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Current Bimmer
2004 X5 4.4i Sterling Grey Sport/Premium

Past Bimmers
1991 318I Alpine White
1995 740I Alpine White
1991 525I Schwartz
1998 323IS Scwartz
2004 330CI Cabrio Titanium Silver Metallic
1995 540I Schwartz
2000 Z4 3.0 Titanium Silver
2000 330ci Coupe Titanium Silver