There's a big difference between driving it every now and then, and not driving it at all. If you don't drive it at all, you can leave the oil in there indefinitely.

If you drive it every now and then, you have to get it fully warmed up and blown out, or you will be parking it with crap in the oil. That's why I would err on the side of caution and change it every 6 months. Blowby is nowhere near as much an issue as it used to be, but it's still a consideration.

 

I have a one of seven 1989 Mark 7 that has been a garage queen. It's never seen rain to give you an idea.It has 34,000 one owner miles on it. I drained and refilled the oil last week and took a midstream sample for testing. Wear metals were into the double digits but none over 17 ppms. The oil is Chevron Supreme, an SL rated oil and was put in the engine originally in 2004. The oil has not oxidized obviously and is still healthy. As long as the crankcase is still tight and sealed, time means nothing to oil, only mileage. Now if the oil fill cap is missing or broke, all bets are off. The issue is keeping free oxygen away from the oil. The crankcase is normally filled with combustion gases and no oxygen so as long as that doesn't change, time means nothing. For vintage engines with a down draft pipe and breather this does not apply and changing every 6 months is mandatory.

 

10,000 here!

 

I change mine every 5,000 and I use just regular Castrol oil. When we fill out the oil change sticker at the shop I work at we put for the customer to come back every 5,000 miles unless we put synthetic oil in it. Then we put 7,500.

 

5 to 6k every oil change.. Oil changes are cheap so why push it? 39.99 with motorcraft syn blend, filter and tire rotation at the dealership.

Mom has a 99 cougar and its been a garage queen since the day it was bought in 99. No wet roads, never sits outside,never had the windshield wipers turned on. The trunk has never been popped since it was bought. As of last month it had 10,000 miles on it. I take it and get the oil changed every year when the inspection is due.. Probaly overkill especially only putting 5 to 600 miles a year but its still piece of mind.

 

Change it when you can see broun oil on your dipstick and metal fines on your rag. It s way more dirty in the oil pan than it is on your rag or stick !

 

Oil gets "brown" very quickly . . .

 

Im a daily city/hwy driver and I put 2,000-3,000 miles every 3 months on my rig. During the summer I will put on 3000 miles in 3 months easily when we go camping and while I go get firewood for the winter. Is the Motorcraft 5w 20 good for 5000 miles?

sent from my tablet

 

absolutely

 

Yes. Motor craft synthetic is good for 6000. Thats where I change my Vic. It would also depend on the driving you do. I bought my Vic to travel from Salt Lake to Des Moines So in that 6000 over 4000 of it is pure freeway. If I drove it in stop and go traffic allot I'd probably change it more often.

 

Thanks KingRanchCoy. I'm about to go outside right now and change the window sticker!!

 

thanks for the insight, I've always been used to changing my conventional oil every 3000 in all my other vehicles. The 5.4 3V has been quite the discussed engine but I enjoy making sure its maintenanced and this forum has helped me out alot!!

 

Ford even tells ya to do it every 5k with the new winder sticker when you get that SynBlend

 

The oil change for dino oil is 3 months or 3 thousand miles which ever comes first. Second thing the engine and transmissions are not sealed systems. There is no such thing. I had some shop tell my customer that. Till I took out the transmission and showed him the vents before I overhauled his transmission. Now if you want to buy cam phasers then do the 5k to 10k oil changes. I have a shop full of those customers f150s. I dont even argue with them I just tell them thanks for your biz. And see you soon again.

 

And have to say if ford put 10, 000 miles on the sticker you think they care if your cam phaser goes out? And your truck has no warranty left? Come on think about it. The new engines are going to the 5k and past mark. But those new engines do not have prone cam phasers either. And also the newer engines have a different filter as well. I change my oil on time every time. I have over 120k with no issues either.