I'm at 105,000 miles on my Ranger, it's a 2004 4.0L V6. Today I ran Seafoam through the brake booster and changed out the plugs and wires, they've probably been on the truck now for about 40,000 miles. All of the plugs looked fine, there was no fouling to them, they were still at the gap I originally set them at, just a little bit rounded at the electrode. What caught my interest was a wet looking thread on my 2, 3, 5 and 6 cylinder plugs. It's not really bad, just slightly wet and smelling of oil. Does anybody know what this might mean? I am not hearing any engine knock or valve tapping, if that helps.

 

oil/compression rings on the pistons are done?

 

not entirely laz, unless op's truck has been dogged on for all of those 105k.

op, do you have a rough idle issue?

 

No, idle's fine... nothing seems to be out of the ordinary with the truck.

I don't think it would be the case, but could it have anything to do with running the Seafom through the engine an hour and a half before I pulled the plugs?

 

I had the oil on the threads, and it turned out to be a cracked head.. Now i also had other symptoms as well though..

 

u got an air filter u oil up? only other way i see oil getting on the plugs

 

leaking valve seals?

 

Nah, paper air filter.

How else could I tell if I had a cracked head or leaking valve seals?

 

compression test. Also your local mechanic should have a scope he can stick into the spark plug hole and look at the internals

 

being on the threads i dont see it geting there from the cylinder, more likely from an exterior leak. the op did say the electrodes were fine

 

Never said it was from the cylinder. Said it was from the head.. You do know that the spark plugs screw into the heads, right?

 

An exterior leak would be visable around the area the spark plug is threaded into, wouldn't it? It would be odd also to have that on the rear 4 of my 6 cylinders. I didn't notice anything that looked stained around the plugs.

Is there a tool that I could possibly rent to do the compression check myself, and how difficult is it to do?

 

Quote
It would be odd also to have that on the rear 4 of my 6 cylinders.

Not if the valve cover gaskets were seeping.
It may not be obvious , no large oil runs down the side of the engine ,no puddles around the spark plugs, but try tightening the valve covers down.

 

Alright, I'll take that on for tomorrow. If anybody has any other ideas, please post them up.

 

If the plugs were not tight enough or the gasket did not seal the oil will be pushed out.

There is oil in every cylinder and its supposed to be there. Every engine burns oil. The amount it burns is the key.

If your covers are clean it had to come around the threads. Or a spill from a long time ago.

If the electrodes looked good on the old plugs you should be fine. If your **** compression and leak down tests are in order.

 

I had oil on 2 of my 6 spark plugs.. There was stuff inside the spark plug hole as well if you stikc your finger in there and pull it out, you whould be able to get something out of the threads..

You probably dont have a cracked head.. But i would still get a compression test done.. any ford dealership can do it shouldnt cost more than 30 bucks.

 

The plugs may not have been tightened up enough. Though it could do with the oil lubricating them, those 4 did come out much easier than the other 2 plugs. I'll get a compression test done soon. Thanks for all the info guys.