Ford Van Burning Oil

I have a 2000 E350 15 passenger Ford Van with 125,000 miles on it. I am burning a quart every 500 miles. The van produces a cloud of black smoke occasionally when I start it. Maybe once every 10 starts or so. It seems to be more prevalent when the van is parked with the engine downhill. About a year ago, I switched to high milage oil. Could this be part of the problem? Or is there anything other than a rebuilt engine that will help?
Thanks

If there’s a cloud of black smoke on start-up, there’s unburned gas coming out the exhaust.

The first thing to check for is the fuel pressure regulator that’s leaking. http://www.rockauto.com/catalog/moreinfo.php?pk=1320208&cc=1362350

Locate the fuel pressure regulator on the fuel rail. Start the engine and let it idle for a minute. Shut the engine off and remove the vacuum hose from the fuel pressure regulator. If gas leaks out of this connection replace the fuel pressure regulator.

Tester

The combination of smoke upon startup and oil burning of 1qt/500 miles leads me to believe you may have worn valve stem seals

I could be that raw gas has repeatedly washed the oil off the cylinder walls, causing cylinder and ring wear that has turned it into an oil burner.

The combination of an occasional cloud of black smoke on startup, excessive oil usage, and a 13 year old 15-passenger van with 125,000 miles suggests to me that not only is an injector probably leaking, and perhaps a valve stem seal leaking, but the engine is also well worn.

I’d start by checking for evidence of a leaky injector, but I think I’d want to do a pressure check before spending any more money on this beast.

In addition to what mountain bike suggests, I would also do a thorough ignition check to see that all spark plugs are firing properly. I agree that at this age a number of things could be wrong.

I’m assuming this is not a diesel and is one of the gas rigs. Other than agreeing with everyone else, you might consider having a vacuum gauge connected and that may provide a heads-up about going forward with both a dry and wet compression test.

The vacuum gauge is quick and easy and will reveal instantly if there is a compression problem which may then require a test to verify a problem in the engine top end.

I agree with db4690 that the problem may be valve stem seals. On many engines, these can be replaced without removing the cylinder heads. A spark plug is removed and an air hose adapter is screwed in its place. An air hose is connected and the air pressure holds the valves in the cylinder up while the keeper is removed and the seal replaced.
Leaking injectors may also be the cause with raw gasoline being dumped in the cylinders while the van is parked and diluting the oil which makes it burn off more quickly.
The question I have is how the van is used. One doesn’t have a 15 passenger van unless it is ued to transport people. If it sees just local service, then have the fuel injectors and fuel pressure regulator checked. If the oil consumption is reduced, that is great. If not, it may be more economical to live with 500 miles per quart. On the other hand, if the van is used to transport people on long distances over interstates, then check for other causes. If the van is otherwise in good shape and safe, maybe it is time to think about a rebuilt engine for this type of service.