The 603 will start quickly without a block heater below 10F, I've done it for decades. Below zero (F) it will need to crank, less than 1revolution, and then it will puff and run rough. If yours doesn't, you need more than a block heater you're putting lipstick on a pig.

The block heater helps the engine start more smoothly, and at seriously cold temperatures (below what I've ever seen in mid-Michigan) it might become a necessity, but most cars sold in my area of Michigan never even had cords, ... because they started fine down to and below 0F.

Fix the problem, not the symptom.

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Gone to the dark side

- Jeff