93 original plug #2 white

[mlunsford]

I bought a 93 4.0 all original. Changed the plugs. Plug #2 was white. After new plugs and a few miles plug #2 is white again. The compression check showed 150 in all cylinders. It is using some coolant. Head problem or intake ?
Any way to be sure?

Yes I have 2 rangers a 99 and a 93.

 

[RonD]

Do the Glove Test, it is free and will tell you if #2 has a crack or leaking gasket ring.

Cold engine
Remove rad cap and overflow hose
plug overflow port on rad cap opening, use vacuum cap, or hose with bolt in the end or ??
Put a latex glove or balloon or even a condom over the rad cap opening, seal it with rubber band or zap strap or ??

Unplug the coil packs connector, you want a No Start

Now crank the starter motor and watch the "Glove" if there is a leak from a cylinder to the cooling system the "glove" will pulse/jump each time that cylinder is on it's compression stroke.

If it does jump, remove #2 spark plug(so no more compression in #2) and crank starter motor again, if it doesn't jump any more then #2 does indeed have a cracked head or blown gasket ring.

 

[mlunsford]

thanks will do the glove test on both rangers 93 and 99.

as far as head gaskets - is there a recommendation ?

I read somewhere about a felpro torque head gasket ?

 

[RonD]

4.0l OHV only has 9.0:1 compression ratio so no need to spend extra money on special head gaskets.

Fel-pro are what I have used and they work fine

The 4.0l OHV heads have a weak spot in the casting between the valve seats, if over heated the metal in the head expands too much and they can crack at that location.
If you do have a cylinder to cooling system leak then have both heads pressure tested, or if crack is visible replace that head.