engines
There are many internal combustion engines powered by gasoline, diesel, propane, or natural gas; hybrid vehicles, plug-in hybrids, hydrogen-powered fuel cell vehicles, and all-electric vehicles. Fuel-powered vehicles have an advantage due to their limited range and high battery costs. Some options require a network of refueling or charging stations.
An external sign of wear on the valve stem seals is the short-term appearance of blue smoke from the exhaust pipe after starting the engine and when braking the engine after a long drive under load
If you find traces of oil leakage through the camshaft seals, first check to see if the crankcase ventilation system is clogged and if its hoses are pinched, and correct the problem if necessary
