You must use the manufacturer's recommended weight. Diesels run hotter than automobile engines so you may need a heavier oil. Read your owner's manual. Also at the oil intake, it should list the type of oil needed. It is the weight of the oil that is important. If it requires 20W-40, do not put in 5W-20.
NO, do not use diesel oil and a gasoline engine.
No, putting gasoline in a diesel will destroy the diesel engine.
You mean "motor oil for diesel engines," rather than "diesel oil the fuel." And the answer is simple: No. It will not. All the popular and not-so-popular brands of diesel engine oil sold in the US carry two ratings: a "diesel engine rating" and a "gasoline engine rating." They do this because most trucking companies also own some gasoline engine vehicles, like pickup trucks for driving to the truck dealership on parts runs, and an oil rated for both gas and diesel engines allows them to put the same oil in all their vehicles.
Yes, never put oil formulated for a diesel in a gasoline engine.
Refining oil into gasoline and diesel.
If it is a diesel on the frame and it has a injector pump on the motor. If it is gasoline it will be in the fuel tank or on the passenger side of the engine at the front of the block.
I am not sure what you are asking but putting oil for diesel engines in a gasoline engine with some oil in it would not be good, or vise versa
No
No, absolutely not. Diesel engines run at a much higher compression than gasoline engines. A typical gasoline engine has a compression ration of 10:1 while the typical diesel compression ratio is 20:1 or higher. The diesel burns fuel through compression and the gasoline burns by ignition. You must use an oil with an API rating of C (Compression) in a diesel. Gasoline engines use API rating S (Spark). Use exactly the proper weight and API rating as listed in your owner's manual. Use a gasoline motor oil and you will destroy that diesel engine. -IMPROVED - I totally agree with Almostevil. I own a diesel and this is what I use. So, I didn't "improve" his answer but do back it up!
Gas: 5W30 synthetic, gasoline-rated oil. Diesel: 5W40 synthetic, diesel-rated oil.
There is not a whole lot of difference if you are using the oil in an older diesel engine. The diesel oil of today has special additives to combat the soot buildup in the oil from the EGR. The diesel oil will get dirty a lot sooner on the late model engines. A 15w40 for a gas engine can be used in a diesel.
More than likely no damage was done. Drain out all the oil and fill it with the correct weight diesel oil.