I have a 2000 F150 with the 4.6L with 230,000km. Lately upon start up, there is a fairly big blue cloud of smoke. Now it doesn't have any blue smoke when I'm driving, but I also know I'm using quite abit of oil. What are some possible causes? Am I going to have to look at something on the heads? Or am I looking at piston rings? I'm alittle bit stumped, and don't exactly want to pull something apart and it not be the problem. Or am I better off just getting an engine from the local wreckers and putting it in? I am just getting sick of having to put in 2-3L every two weeks.

 

Blue smoke is oil smoke.

Blue at startup is *almost* always caused by leakage past valve seals.

Valve seals can be replaced without taking the heads off. Therefore, it should be relatively inexpensive.

I'd do a careful compression test before doing anything to get a feel for the general condition of the engine. If it passes, get an estimate for valve seals.

Flagship

 

Flagship is correct. 99.9% of the time blue smoke upon startup is caused by worn valve seals. When you shut the hot engine off the oil in the cylinder heads will leak by your valve seals and pool on top of the pistons. When you go back out to start your vehicle the engine burns the pooled up oil off the pistons. That's why the smoke will start to go away almost instantly after startup.

Worn piston rings will generally always put out blue smoke once the engine is warm. And more so the higher you rev the engine lots of times.


As far as what route is better for you is really up to you. If the engine is mechanically sound other than the valve seals and you have access to a good mechanic that won't overcharge for the valve seal replacement I would go that route. But if you are going to wind up having to spend a considerable amount of money on it you might would be better off picking up a low mileage junkyard engine. Then you would have an engine with low miles and most junkyards will give you a 1-3 month warranty on engines also.

 

I was told by an independent master mechanic who runs his own shop that a valve quide seal replacement job on a 4.6L costs approximately $1000. Often times the consumption of oil does not entirely stop when the valve guide seals are replaced because oil continues to be pulled past the rings on many higher mileage vehicles. The customer frequently thinks he wasted his money and blames the shop.

Whether or not to bite the bullet and change the valve guide seals seals should depend on how much longer you plan to keep the truck, what condition the rest of the truck is in, and how much it bugs you to regularly add oil.

 

Exactly how MUCH oil are you using? What weight of oil are you using?

 

My 1994 Ranger's V6 also had the same problem. I was burning 1 qt of oil every 1000 miles. Every dealer I talked to (Ford or otherwise) said that was acceptable oil consumption, and it wasn't worth tearing into the engine to replace the seals. I ran that truck for another 70,000 miles before trading it in. You would have never known there was anything wrong with it once that puff of smoke in the morning was gone. So, I guess they were right.

 

Actually, to be really technical about it, worn bearings are usually more the culprit when oil burning is noticed during running. The cylinder walls are lubricated by oil sling off from the rod bearings. Obviously, the amount of oil is controlled by the clearance. More clearance, more oil. It doesn't take too much for the oil to be greater than what the oil rings can handle, especially when they're worn too.

That said, when you've got the engine down far enough to replace rings, bearings are a no-brainer. I have seen oil burners fixed simply by dropping the pan and replacing rod bearings.

One more reason to follow manufacturer's recommendations for oil viscosity: cylinder lubrication.

 

my 01 was doing the same thing and i just changed the PCV valve and that was all, no more oil smoke.make sure to use a motorcraft.

 

good info; I've got an 05 with about 19K on it, and I noticed the other day I put out some smoke on the first start of the day...looks like I'll be taking that aftermarket warranty as my intial has expired (36 months)

 

I've been using 10w30 oil. And I've recently switched from synthetic to just mineral oil. But the smoke has been happening for quite some time now. Since around the 190k mark. I've just aquired a 5.4, so I'll be rebuilding that one.

 

You guys are talking about engines with some miles on them. Here is my situation. I have a 2000 5.4 Lariat. I had a new motor installed 65,000 miles ago. It started using 1 1/2 to 2 qts oil per oil change. Under warranty they installed a new motor last week. I have 500 miles on this motor. I drove home from work parked the truck. 2 hours later started it up and had a large cloud of blue smoke. What is your best thought of what is going on since this is a new motor. The motor is an ATK purchased from NAPA. Any ideas???