Having spent 38 years in the fire service, I recommend nothing less than what we call a 10 pounder.

A powder extinguisher containing around 8-1/2 pounds of agent - 2A 10BC minimum - AND some water! This extinguisher will be about 15" tall and 4" in diameter. Unless the top is made of metal, it cannot be serviced. The green band on the pressure gauge represents pressure from freezing to about 135 degrees - the white stripe, room temperature.

Small extinguishers can have a discharge time of as little as 14 seconds - many people cannot even figure out where the agent is going in 14 seconds.

Obviously, if the pressure is low, it has leaked out, If the pressure is high, that may be a sign that there is a reaction going on - and the bottle may explode.

If you grab the extinguisher and there is no pressure - spin the top off and sprinkle the powder on the fire. Can't spin the top off? Stuff it under a tire and spin the bottle. You will be stronger than you usually are. I have seen a young lady pull a section out of a wall when she forgot to open the bracket on a small extinguisher.

You cannot use a little bit of powder and save the rest for another fire. Powder gets in the valve seat and the pressure that is left will be gone in a few days.

Powder and gas agents merely interrupt flame production. CO2 displaces oxygen (air).

The classic ingredients of a fire are fuel, oxygen, and heat, scientists added chain reactions to the formula when they tried to explain how powdered chemicals work as they do not remove any of the three classic ingredients.

Thank goodness that your old car is made of metal - plastic inner fenders and heater modules are murder to extinguish.

I have exhausted 20 pounders on car fires and not been able to achieve complete success,

You really need some water to cool the area so that it will not re-ignite.

Carry a gallon of water in your trunk to cool things off after you knock a fire down with your 10 pounder.
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'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 485,000 miles put on 9 bricks