MetalThrashingMad

Im certainly no mechanic...But Ive encountered the dreaded white gunky oil cap before many years ago on another vehicle. The other day I wanted to top off my oil and low and behold I removed the cap on my 94' 5.0L XLT and there it was on the inside of my cap...So I checked the expansion tank and ugh!!!....nearly bone dry, with an oily residue look to it. My concerns turned to horror as I realized I probably have a BIG(and expensive) problem on my hands. What I find funny is when I check my oil with the stick...The oil looks like any other used motor oil with no white gunk to it at all. Im going to drop the plug on Friday at work and see what comes out. I know I have an internal leak somewhere in the engine(headgasket) atleast I think I do...Im afraid to drive it in case I trash my engine. I guess my question to you all would be..Why does my temp gauge read normal(consistantly at the same level) after warm up and the engine seems to run just as smooth as it did 2 months ago...or any other month for that matter? Heat works great too! Also...no external leaks to be found. I fear the worse but I need the vehicle to get me back and forth to work. Any suggestion are greatly appreciated in advance....Sorry for the long post...but I'm in dire need of some advice here.

dirtcrew51m

Try to flush the system, clean the tank, change the oil, and see what happens, also might be an intake gasket, head gasket might be leaking in the coolant, try to fill the radiator, start the truck, with the pressure off the cap, and watch for any bubbles. As far as the heat, the engine will run normal temp if the thermostat is working properly regardless if there is a leak.

mitchalvin

The white gunk on the bottom of the oil cap could just be condensation. Check your pvc system to make sure that it is functioning properly. The oily residue on your cooling tank could be from old antifreeze. What does the coolant in your radiator look like?

ymeski56

X2. When regular oil begins to break down, one thing it does, is begin to carry moisture (which then becomes acidic, but that's another story). You live in a cold part of the country, which would have a greater propensity for condensation to occur cause heat attracts moisture. I'd desludge the engine (The sludge can really carry moisture) by adding "Seafoam to the oil, and running it for 50 miles or so. Might as well do the air intake while your at it. Drain & run 20% "Lucas oil stabilizer with your new oil. Synthetic would be best, but until
you know for sure what the problem is, you might not want to pop for the extra expense.

dr_bowtie

X3

On Fords this is common...moisture in the crankase will cause this...the PCV can pull outside air with moisture in it inside the system and this is what causes the moisture...