Yes
Yes
It could either have a gasoline engine or a diesel engine
you will have a bomb. your engine could explode from the increased compression of a diesel engine
No , a diesel engine doesn't have sparkplugs It could have glow plugs
Not really. You could start over and redesign an engine to be able to run on diesel but it would be completely different from the original.
Flex fuel does not mean you can use diesel. It means the engine can run on pure gasoline or on E85 gasoline. If you put diesel in this vehicle it simply will not run. Diesel can only be used in a diesel engine.
Minor problems will be increased engine noise and vibration, jerkiness when putting it to gear, etc. Worst case scenario will be the engine falling off from the mountings...
You could damage the Engine because Gasoline is potent than Diesel
An engine might sound like a diesel at operating temperature if the engine was a diesel or if there was an issue with the manifold. Sometimes gases escaping the manifold cover could cause the engine to sound different.
Not in a warehouse situation, outside use only.
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Rudolf Diesel invented the diesel engine which now powers many large vehicles
If it is a diesel engine it could be the glow plugs.