My son was driving his 1993 hyundai excel, heard a sound like nails in a can it lost power wont start no obvious holes in the engine block and oil is not milky what could the solution be? i did notice the transmisssion dipstick is missing

Oooooooo... I think that engine is GONE, Miguel... not even rebuildable, I think it's ruined.

The drain plug or oil filter may have been loose, allowing the oil to drip out, but since you didn't find any oil on the ground, that's doubtful. What's MORE likely is that you threw a rod (the rattling noise), and that rod broke a hole in the side of the crankcase and blew all your oil out the hole. If I'm right, that engine can't be salvaged... none of its internal parts are good for anything but scrap metal now.

Hi there sound very much like a failed fuel pump, they are electric and is possibly under your back seat, turn ignition on a listen closely for a humming noise, if not there then I would say you need to replaces the pump, check to see if you have power to the pump first, use a test light, hope this helps cheers good luck

could be the oil pump has failed grinding sound then knocking sound could also be the timing is out or failing that something forren has got into the engine. check all these out and don't run the engine you are making the engine worse. if pump for the oil has gone and the engine has been run can mean a new engine. if timing belt has moved could be a new head will be needed. and pistons. failed oil pump does more damage in the long run as the hole engine needs oil.

check oil to see if there is rad fluid in it. if there is you have a cracked head or head gasket. if no rad fluid in oil, check for a spark.pull out a spark plug attach spark plug wire hold close to engine block with gloves and turn over engine. it is best to have someone with mechanical know how to do this,i.e. friend or nieghbor

start with the easy stuff, is the serpentine belt still on? you might have thrown it.

Dosent sound good. Oil light on means you lost oil pressure. and the knocking sound is the damage done due to low pressure. Start looking for another engine or another van.

Sounds like it was frozen, how cold was it ? most likely the coolant wasn't mixed for that climate, when you say a hole, any chance it could be a freeze plug (it will be round and copper)

I would really be concerned about the antifreeze in oil, sounds like head gasket at least or head, block problem, even if you dont see antifreeze leaking, the engine can burn it and exit through tail pipe-white smoke or steam (beyond just cold start-up)

Check engine block ground.
Check starter.

sounds like you are low on gear oil