My dad has been having a problem with his 96 es300. When he starts it up it starts smoking and burning a lot of oil. After it runs for a min it goes away. What do you think it is?

valve guides and or valve stem seals... it probably smokes while decelerating but it would be hard to see unless you were following his car...

Yea its not that i've been behind him in it before. He thinks its the oil sending unit but were not sure.

the oil sending unit may be leaking on the exaust but you would notice it when you park it after driving... it would be smoking from under the hood and leaking from the sending unit next to the oil filter... if its smoking out the exaust when started its the guides

Yea i'm not sure where its smoking from i'll have to ask him

So the smoke is coming out of the exhaust and correction on this he thinks its a cloged oil return. Can anyone chime in on this?

there are 3 huge oil return holes on each head if your dads oil returns were plugged yes that would contribute to a problem that already exists (guides) but it it unlikeley that they are plugged if he has changed his oil fairly regularly... the intake valves in particular will suck oil past the guides as there is a high vaccum condition at idle and decelleration... also hot oil will seep past the guides when the eng is shut down and you will get a large plume when you first start it up... the front cover is easy to remove if you feel that the returns are plugged you can see them with a flashlight...

Yea he's gonna take the cover off and look. We don't know the history of the car. He owns a car dealership and bought the car at the auction.

If its smoking in the engine compartment and you just had a service for the engine then go back to the person and tell them they screwed up. Lexus did that to me...they reported "no problems" but it was gone the time I got the car back. They apparently forgot to put a screw in tight enough or a hose and it came loose and leaked oil on the engine -.-"