loosing oil 5.4 motor

[nuts]

I have a 2004 superduty van with the 5.4 motor and 85000 miles. It is constantly running low on oil. It does not smoke on start up, exhaust colour is not blue or black. Tail pipe is clean. There is no oil leak marks on the motor or driveway. I am losing about 1 liter of oil every 800 miles. I am using the recommended 5w20 oil, in the synthetic form. Rad fluid is good and no discolouration, oil colour is fine also, so I don't think its a head gasket. I think that it is being burned off. How can I tell if something worn in the motor and passing oil? What else should I check? Do these motors have oil issues? This is my work truck and I can not afford to have it down. Thanks in advance.

[rhandwor]

I would check around the intake clean the PCV valve and check for something in the intake sucking oil and burning. I would think valve stem seals but this would be noticeable at morning start up.

[nuts]

Thanks, I will replace the pvc valve . I never changed it since I got the truck, some 20,000 miles. The motor looks clean, no evidence of oil leaking.

[nuts]

Is there a pvc valve on a 5.4? My parts guy says he has no listing for it. Does any one have any part number? Thanks, Nuts.

[rhandwor]

I had a 1997 Ford F-150 with a 5.4L and I thought it had one. I wrecked it about 5 years ago. I'm not sure call Ford parts department if they have one get a part number.