My v6 3.0 seems to have a knock now. I have two cars so don't drive it full time. But it seems to happen more when cold then go away when it warms up. I may try to change the plugs. The truck has 225,000 and is a 2000. Recently had the front and rear converters replaced. Knock started after. About two weeks.
Are the plugs easy to change on the 3.0 v6?
Any ideas if the knock is the real deal or something less than major?

 

Just have to wait and see, if its a rod or crank knock then nothing much you can do about it at this time, just keep driving and let it get worse which it will

If its an exhaust manifold leak then that will also show itself with lean code on that bank

Cold engine
You can take the fan belt off the crank pulley
Then start engine, battery light will stay on, no alternator
Engine bay will be VERY VERY Quiet, so you can hear engine noises better
You can ONLY run the engine without a water pump for under 2min, the shorter the better

See if you can get more info doing that

 

OK I just wanted to put a little more info in. Truck had some sort of seal leak in rear. Main or cam. Old owner said he replaced main. Dipstick tube for oil is weird. It has no outward taper for oil stick. Oil stick was just resting atop of it. Not inserted. I measured the tube at a junkyard and mine seems to be proper length. I grinded down the plastic on my dipstick so it would fit flush into the tube. After putting 4.5 quarts in after changing filter the oil would not line up to dipstick where it should have been. It was less. So not sure if the dipstick was correct. Got one from junkyard that was different from 00 Ranger. Had to grind it down also. But am not using it. I mention these things because I am not sure where the knock came from. It is possible that I let the oil get low enough to cause it. The drip never hits the ground. It just has droplets near bottom of seal.
I don't know why dipstick tube is not stock but length seems correct. Anyway that is extra info.
One more thing. On last oil change I used one quart of Lucas Engine Oil Stop Leak in place of one quart of Motorcraft oil. So I don't know if that started the trouble but it started after last oil change which was within the last month or so.

 

Rev it pretty high a couple times if it’s major it’ll sling a rod through the side of the motor if it doesn’t do that it’s not major

 

That could be what started it. I drive both my 20 year old cars conservatively. I get on gas if I have to but take it easy most of the time. Well recently started having some problems with the rev limiter engaging. So I started purposefully getting on the gas when I did not need to. To clean out the carbon. Anyway i can hear the knock now when driving slowly next to a building.
I hope that it is something like spark knock or a lifter. But I think its a rod.
So I don't want to rev it and hurry along the problem.

 

You can determine if its a rod knock if you can hear it at idle

Rod knock noise happens only when that cylinder fires, its because there is a gap between journal and rod/bearing
Since full cylinder ignition only happens After TDC the cranks journal is on the way down and if there is a gap its largest at that time
When cylinder fires that closes the gap instantly and makes the metallic "knock" noise

So if you disable spark in each cylinder, one at a time, the Rod Knock will go away when effected cylinder doesn't fire, it will misfire of course, lol, but no "knock" noise

Not that it is that helpful to know which rod is failing, but is helpful to determine if it is a rod knock

You can take fan belt off crank pulley on COLD ENGINE
Then start it to see if you can hear the knock
Engine bay will be very quiet with no fan/accessories turning
But you can only run the engine max. 2 min without a water pump

 

either way if it’s a rod knock your motor is screwed anyway so rev it up a few times if it slings a rod find a motor to swap or junk it. If it doesn’t sling a rod that’s not the problem

 

Just wanted to say I do not think the Lucas Oil Leak Stop was the problem. I took it out, but before I did it may have worked enough to stop the oil burning smell. So I think it slowed the leak. And it wasn't in long. I don't think it was a rod knock. Because it goes away. Thanks for the posts.