MY 97 4.6 EXPO HAS HAD A WHITE PASTY RESIDUE ON THE OIL CAP, I STOPPED AT FORD AND ASKED ABOUT IT. SERVICE TECK SAID IT WAS NORMAL IN COLD WEATHER. I HAVEN'T LOST ANY COOLANT. READ SOME POSTS ABOUT ROMEO ENGINES HAVING BAD HEAD GASKETS OR CRACKED HEADS. I TOOK IT TO FORD HAD A COOLANT BG BACKFLUSH. WHEN I GOT HOME I THREW A BOTTLE OF BARS STOP LEAK FIGURED WHAT THE HELL BETTER THAN PAYING $1400 TO HAVE THE TOP END BROKEN DOWN TO LOOK FOR A LEAK. THE ENGINE HAS 170,000 MILES. RUNS GREAT.I RAN THE TRUCK FOR A WEEK AND THEN CHANGED THE OIL, I HAD NO ANTI FREEZE IN THE OIL, AND THE OIL WAS NORMAL COLOR NO MUDDY BROWN AS YOU WOULD NORMALY HAVE WITH COOLANT GETTING INTO THE OIL. WOULD ANYONE KNOW IF THERE COULD BE A PROBLEM IN THE EMISSIONS THAT WOULD AFFECT THE PCV SYSTEM AND CAUSE MOISTER TO REMAIN IN THE CRANKCASE. I HAVE GOOD VACUME ON THE PCV, SO LETS SAY IT HAS ME STUMPED. THE PROBLEM FIRST STARTED IN OCT. I HAD CHANGED FROM MOBIL 1 TO CONV OIL. I WAS WONDERING IF IT WAS A CHEMICAL REACTION. ANY INPUT WOULD BE HELPFUL. THANKS BG97EXPO

 

I don't know what it is but I have a 4.6 and I have the same white pasty film on my cap every winter too. I change my own oil and have always used conventional, never found water in mine either. I would have to say the dealer is right in this case. Vehicles I have had in the past did this as well in winter, or cool moist weather.

 

This is normal. If you change your PCV valve it may help. If you think about it, moisture rises. This filler neck is the highest point on the engine & has quite a bit of cold air (causing the moisture to condense) flowing around it. This tan paste is a product of the design of the engine.

 

medic nailed it. It is normal and just a product of the oil fill cap placement being so much higher off the valve cover. It gets plenty of airflow over it and no direct heating, so it is one of the coldest places on the engine, and any moisture rises to the top.

Both of my trucks exhibit this behavior, the 97 slightly more than the '99.

So long as no antifreeze is going anywhere and the oil looks fine at changes, this is a non issue.

 

yup it is normal as long as it is slight. also if you do a lot of short trips it will be a little worse.

I would get that bars leak out of there asap! you just paid for one of the best flush's there is (BG) and then put that old fasioned stuff (Bars) into a tight coolant system.

just my .02

 

Just an idea. What would happen if I blocked off the current hole for the PCV valve, drilled a hole in my oil cap, and placed the PCV valve there?

 

THANKS FOR THE INFO GUYS, I'M GLAD THE WHITE STUFF IS NORMAL. I WILL CHANGE THE PCV VALVE JUST TO SEE IF THAT HELPS. I WAS GETTING A LITTLE ILL WHEN I WAS PRICING REMANUFACTURED LONG BLOCKS. A HOLE LOT OF WORK FOR THE MONEY. THANKS AGAIN

 

Thanks for the info guys.

I have a 97 4.2L with only 78K miles. When I took it to the dealer he asked how long had I noticed the white paste on my oil cap. ( About 2 weeks ). And that they could do some testing to check it out.
Im still not out of the woods yet because I "have been" missing some anti-freeze. About 3 weeks ago I noticed my heater stopped working, I was about a gallon short of water.
But the only sypmtom I have seen is the white paste on the oil cap. The oil on the dip stick looks ok.
I will keep an eye on it, but I feel MUCH BETTER after reading these posts.

 

I’m going to express my tentative relief as well. I have a ’98 4.6 about to turn 70k, probably this week. I changed my oil yesterday and found the white paste too. Looked like chocolate milkshake to me. I knew immediately that it was oil mixed with water so I kinda freaked. Was trying to prepare myself for what it would cost to rebuild the engine. Weird thing was, I didn’t get any water that I could see when I drained the oil. I’m going to pressure the coolant system just in case though. Hopefully I can just attribute it to the weather. Here’s to hoping.

 

My 2000 5.4 with 80,000 miles showed it on the oil cap for the first time at my last oil change and i drive 135 mi round trip a day so it's not due to short trips it must be moisture getting in around the seal on the cap.

 

Well, I borrowed a Matco coolant system pressure tester and pressured it up today. To my dismay the needle started to fall very slowly. Although my heart sank, I figured I'd go ahead and check the hose connections. Guess what....I found a leak! one of the heater hoses had a slow drip near the back of the engine. Although it was difficult to reach, I repositioned the hose and clamped it back down. The system holds with no pressure drop now!! I guess the white paste was just from condensate. For peace of mind I would recommend that you all borrow/rent/buy a coolant system pressure tester and check it out.

CHL

 

One day is a little soon to assume the "white paste" is gone isn't it? For your piece of mind, I hope so. Personally, I have seen it on every vehicle I have ever owned when it got below 40 degrees, for a certain period of time, doesn't bother me in the least but that's just me.

R.K.

 

Well, condensation is one thing, and while I don't like it, I'm not going to worry about it. What I was so happy about is that my source was not from an internal coolant leak.