I have noticed some oil burning (blue smoke) after my 2002 F150 4.6 idles for a while.
I have read that using an oil with a higher viscosity such as 10W40 (high mileage) would reduce or stop the oil burning from possibly leaking seals.
I currently use the recommended 5W20. I have approximately 160,000 miles on the engine.
Would switching to 10W40 cause any problems?

Appreciate all comments.
thanks

 

Try 5w30 first. Also change out the PCV and make sure it's a Ford part. These engines are sensitive to brand on the PCV. My new 2000F150 5.4L came with a 5w30 oil recommendation. On later models Ford changed it to 5w20. I recently switched my 2002 5.4L to 5w30. It has 166k miles on it.

 

So that would be Motorcraft on the PVC valve?

 

Motorcraft ONLY.

 

Couple things: First, on a Ford there's rarely any situation you'd replace parts with something other than Motorcraft. Maybe if you're modding, yes, but for general upkeep and repairs, stick to Motorcraft.
Second, on your oil, the first number refers to the viscosity when it's warm, the second is the viscosity when cold. In order to eliminate the blue smoke when it's hot, try 10W30. In theory, 5W30 will still smoke like the 5W20 does. I've run 10W30 successfully in a number of 97-03 Ford trucks. I don't know if going any higher that 10W30 will hurt anything. If you live in a cold climate I wouldn't try it. It gets pretty hot here, summer time highs are 95 to 110, winter lows are typically 15-30 above zero.
Supposedly Ford went to the 5W20 oil to improve fuel mileage.

 

​​​​​​​Nope, you got that backwards. 5W is thinner than 10W when cold.

 

5w is indeed thinner than 10w when cold. I wasn't very clear with that.

 

OK, So I have considered all the advise and chose to replace the PCV with an OEM PCV valve and have changed to Pennzoil High Mileage 5W-30 Oil.
If this doesn't do the trick I will do High Mileage 10W-30 at next oil change.
I failed to mention that I pull a 20 ft travel trailer on occasion .. not sure if that figures into it or not.

Thanks for all the comments and suggestions.
Greatly Appreciated .. I will respond with my results after I give it a couple of weeks with the changes.

 

5W30 and 10W30 are the same viscosity when warm.

 

Okay; so first things first, yes, I would go with thicker oil; 5w30 STANDARD ALL-CLIMATE NON-SYNTHETIC (you need the dinosaur oil's slimyness for what you're experiencing, synthetic is too "clean"), but if it's already burning a noticeable amount, I suspect you won't gain much from going hilariously thicker in weight. Oil is supposed to have a sheeting action on the cylinder walls that separates the piston from the cylinder; make the oil too thick, and the piston ends up scraping the oil off the cylinder instead of gliding across it; although I suspect if it's rings, you may as well start shopping for an engine anyway; these things are not cheap to rebuild. On the PCV valve deal; I would suggest pulling the valve covers and making sure the drain back holes in the cylinder head aren't clogged. I've seen some oil burners that are actually caused by an intake that is simply drowning in left over oil that was sucked in by the PCV/Breather that was only there because the head didn't drain properly.

If the heads aren't draining properly, it's actually good news, because then you can put the valve covers back on, and have a BG Systems Flush performed on it. Accept no substitutes in this case, in my experience BG is the ONLY Crankcase flush you want. Be prepared, a genuine BG Crankcase flush is like a $400 date, and the tech will have your truck for at least a half a day, so be forewarned that ANYONE that claims they can do it 30 minutes is a liar. Disclaimer, I'm not a BG salesman, I can't do it for you, sorry; but anyway, other brands it seems are either not strong enough, or are strong enough to really **** stuff up, so be mindful of that when the tech says, "Oh it's the same stuff".

The idea here is, the PCV is supposed to suck up oil VAPOR not oil LIQUID. If the heads drain properly, the PCV valve won't have any oil Liquid to suck up into the intake.

The only other real way you can get oil into the combustion chamber without a bad head gasket/cracked cylinder head is bad valve stem seals or valve guides; any of which would require a valve job (pulling the heads and taking to machine shop) $1500+/- Thereabouts.

My advice, pull the valve covers, and have a look. By comparison, it will cost very little and may prevent other mishaps.

Good luck.

 

I'd try an AutoRX treatment before spending the big bucks for a BG job. That's something you can do yourself.

https://www.auto-rx-plus.com

 

Yeah, well, pulling the valve covers costs nothing if you can DIY it. I guess the next thing you're going to tell him is he should pour kerosene down a rope because that's the cheapest way to stop robbers from chasing him when he's Home Alone..... haha.

Think about it for a moment- If he's got enough sludge built up in the heads to cause the PCV to suck up enough oil to cause blue smoke; that bottle of "cleaner" will be a waste of his money. But whatever. This is a case where I go "OK BOOMER".