What is the problem? How much initial damage could it do?

Hard to say for sure, might have ran out of oil and burnt engine up.

Personally, I wouldn't want that truck. Try to get another one from the dealer. You might be able to get your money back but I doubt it.

engine did not over heat, nothing. I stopped driving it right away. Is it most likely a seal.

if the smoke was white the truck probably lost an injector.. you didnt say what engine the truck has but the 5.4 3 valve has a problem with faulty injectors and when one sticks it had the potential to cause internal engine damage(bent/broken rod) but this doesnt sound like your problem. but a faulty injector WILL cause damage to the catalytic convertor on the same bank as the faulty injector... please respond with what the dealer finds wrong... i have been working at a FORD dealership for 12 years and have had to work on these trucks since day one.

thanks christian. it is 6.0 turbo diesel. it is leaking in the rear oil pan. would that be caused by a faulty injector. the exhaust was white and then dark, but not constant. It did it twice and then stopped.

well i specialize in all diesel and super duty work. if the smoke was white and is intermittent it is an injector. super duty trucks are my babies and i can take them apart front to back and put them back together again. a sticking injector will not however cause the convertor to go bad on a diesel because they are built heavier than the typical convertor to withstand the extreme exhaust temperature that the diesel pumps out. there may be an underlying concern with the fuel pressure that caused the injector to stick though. fuel filter maintenance on 6.0 liters is critical! filters need to be changed every 15,000 miles just because if they get plugged you can take out the fuel pump and in turn starve the injectors for fuel, which will damage the pintle valves in the injectors causing damage and driveability problems.

as far as the oil leak goes, this engine just like the 7.3 will actually stop running when is gets too low on oil because it uses the engine oil to run the injectors. the base engine oil pressure system gets all the oil first and the high pressure oil system is fed off the low(base engine) pressure system. its a leak but not a real issue unless you want it investigated further....

would that cause an oil leak in the pan?

Return the truck for a full refund. It's Lemon Laws for stuff like this. I would ask for my money back and research somewhere else. Sometimes dealers are worst than private sellers. It all depends on the person you are dealing with and how honest they are. People are looking for money and will sell you anything nowadays.

thank you Christian. You have been a big help. I talked to the dealership and I am hoping to get my Tundra back!