Sorry, trolling for extinguisher suggestions, and stumbled here.
I have personally put out 4 fires with handheld extinguishers.
1) my '80 Triumph Spitfire caught fire from a leaky valve cover gasket on my drive home from buying it.
2) a neighbor's landscaper's pickup caught fire on our street as I was driving by
3) Same Spitfire years later while driving with friends. Hear on the radio, Karl, your car's on fire. Pull over, lift bonnet pull trigger from handheld mounted on roll bar, extinguisher was dead. Pop boot, pull out 2nd extinguisher and put out a fuel fire (choke screws backed out of zenith stromberg). Needless to say, everyone was speechless that I had two, but when your car's burned in front of you, you learn. After that, I always use ones with gauges.
4) parked on street during forced evacuations when San Diego was on fire. Surfer's pickup had a can of ammonia glass cleaner that exploded from being in the sun and ignited trash in the bed.
In each of these cases a cheap extinguisher saved a car with minimal damage, usually only hoses.
When I was 16 I set my '76 Rabbit on fire adding oil in the dark on a hot engine. Ran inside and got a cup of water. That worked, but I almost burned my car and my friend's '69 Pontiac Firebird 250 convertible.
All cars can catch fire, and folks who know cars well can often safely stop a fire early before the car is engulfed.
Mechanical sympathy makes us better mechanics and better owners. Ducati dry clutches .... I just don't get it.