When I travel on the highway for extended periods of time I'm lossing oil. It's not going into the coolant. Also the truck easily passed tail pipe pollution test. Looking back this seems to have started when the PCV was replaced just under 100 K with a Bosch. the truck is now just under 125 K. I've always used Mobile 1, except for the first 5 K. The oil was changed at 1 K, 3 K and switched to Mobile 1 at 5 K. I've never had a Ford burn more than a quart between the 5 K Mobile oil changes, and I've put over to 250 K miles on them before something else fell apart. I'm perplexed at the cause.

 

I never heard of a pcv causing oil loss sounds more like a head issue or rings

 

the PCV valve is between the vavle cover (motor block) and the intake manifold. Its purpose is to control the suction of the oil fume in the motor thru the tube into the intake manifold. IF you remove the valve and connect the hose, you will suck several times more oil from the motor than normal. If you use the wrong PCV valve or it is stuck inside, you can use more than normal. My suggestion would be to change the valve and then see what the oil usage does.

 

We have a 2000 f150 Windsor built 4.6 that was acting like valve seals were leaking,smoking @ idle but was only intermittent.It was going through a 2 quarts of oil a week.You could here a rattling on the road but again it was intermittent.
We changed the pcv and problem solved.

 

Replace with a motorcraft PCV and/or you can put an oil catch on. A lot of guys years ago were having trouble with the non Ford valves sucking oil when new.

 

Aftermarket PCV valves often cause problems, replace with a Motorcraft valve and your problem should go away. I'm not one that is quick to buy dealer parts for everything, but there are certain parts where aftermarket just doesn't meet OEM requirements. The PCV valve is one such part.

 

An update, I changed the oil this Sunday. Truck sat all night and I checked the oil before I started it. It was at the lower hole on the Dipstick. Drained the oil, it had all 6 quarts in it. I know better than to check it right after I've stopped, but parked overnight on a level surface?? I really baby this truck, and stuff like that will drive me nuts.

Today I replaced the PCV from the dealer, was only $8.99

 

If it is a '97 or '98 with the remote oil filter (or any other year I guess) it takes a good 6.5qts to be full.

 

It's a 2001 4.6 Romeo engine. No remote filter, just got to remember to turn the wheel all the way to the left to get the filter past steering linkage. I had a F-250 LD, was out of town and took it to dealer that is part of my dealership. When I changed the oil next time I couldn't get the filter out. Turned it every which way. Reinstalled and wiped it off, it was the wrong filter. Took it to the dealer here. They apologized and took care of it. When I picked up the truck, they said everyone in the shop had called and chewed the mechanic out.