Buyer's Guide: Engine and mechanic

The engine and chassis of the Fiat 500 and Fiat 126 are known to be quite sturdy. Nevertheless, the tight budget of many previous owners has left some traces. Here are some typical weaknesses that should be examined:

Engine & gearbox:

Thermostat: The fin beneath the thermostat box needs to open when the engine has run warm...
... otherwise the engine is in danger of overheating during full speeds
... in Winter a cold engine and with the thermostat-fin open means no heating performance for the car interior.
Cylinder head: spark plug sockets damaged?
Faulty or worn out valves mean problems with starting, shaky engine. If in doubt, have a compression test done.
Oil leaks around engine and gear-box
Carburetor: pounded-out throttle shaft
Timing chain rattles
Ignition distributor in worn condition
Poorly adjusted or deteriorated ignition
Clogged oil centrifuge
Deteriorated or loose fan belt
Clattering fan wheel
Gearbox jumps out of gear when moving off or when under stress: this might be due to a gearbox fault and / or a faulty selector rod pilot bushing and / or a damaged or too deteriorated gearchange linkage snubber (= connecting piece between selector rod and gearbox)

Front axle:

Pounded out front steering knuckles and / or transverse links cause difficult steering, little directional stability, little steering self-aligning force, one-sided wearing out of the front tires.
Leaf spring tired out or broken; this is when the leaf spring hits the snubbers above it when standing still or cornering, insufficient suspension.
Damaged or faulty shock-absorbers may be oil-fouled or the dust covers rusted off.
Tires old or damaged

Rear axle:

Drive shaft keying and / or sliding piece keying deteriorated
Axle coupling (= torsion dampers between the wheels and sliding pieces) deteriorated
Broken or heavily corroded coil springs
Damaged or faulty shock-absorbers, may be oil-fouled or dust covers rusted off.
Rear axle shock-absorber suspension rusted through
Old or damaged tires

Brakes:

One-sided effect, may be due to faulty brake cylinders
Long pedal travel, may be due to worn brake shoes
Varying pedal travel when operating the brakes several times, may be due to faulty wheel or main brake cylinder or due to a poorly vented braking system.
Long hand brake lever travel, probably due to deteriorated rear brake shoes.

Miscellaneous:

Fuel tank rusted and / or dirty on the inside
Faulty or poorly discharging fuel pump
Old / faulty battery
Generator does not load: indicated by a red battery light on the instrument board (should not be lit up when driving with high rpm.
Starter-engine with fault
Faulty or deteriorated ignition parts

Of course, the conditions that Fiat 500 as well as Fiat 126 are in today can vary. A deficiency that is not mentioned above can also show up. The above mentioned list of known deficiencies need not necessarily be complete.