I think this is a slightly more subtle question. The early vehicles were fairly simple machines, and could be reliable if they got a great deal of maintenance . Exhaust valves often became leaky and had to be ground and/or lapped into their seats. Connecting rod and main bearings were made of babbit ( a comparatively soft lead alloy) and , since there was no pumped oil lubrication, and lubricating oils were not all that great anyway, they also had to be recast, reamed on a regular basis. A chauffeur was often expected to do quite a lot of this repair: a car shed could have space devoted to the tools and equipment necessary to take apart and rework the engine, and sometimes a non-driving owner might have the car kept at a local garage, where it could be stored and maintained by mechanics, instead of serviced by his driver.

Though there was a burden of maintenance, the technology was fairly simple and so it was not hard for people to learn to work on their own cars. Also, when mass production came in with the Model T, there was a common knowledge base for lots of vehicles: if you were having trouble figuring out why your Model T was running rough at idle, there was likely someone you knew who had tinkered with the problem already and it could be a social occasion. The comic strip Gasoline Alley originally began with several men discussing their cars over a fence.

Rae: The American Automobile