Mechanics

4.9L YELLOW SUBSTANCE IN VALVE COVER

1983 Ford F-100 • 6 cylinder 2WD Automatic • 150,000 miles

I have a 1983 Ford F-100 with the 4.9L (300 straight 6) with a carborator.

My oil pressure has been up and down, and I've noticed the engine seems to be running a little rougher. The other day I noticed a small oil leak coming from my valve cover. Yesterday, I replaced the valve cover gasket and at the back cylinder where the PCV valve is located and found a substance that was yellow mustard color and consistency. When I smelled it, it smelled like oil. I also noticed the same thing in my oil cap, although it was not on that end of the valve cover.

I replaced the valve cover gasket, oil filter, and changed the oil, cleaned the cover as well as the rocker arms. Drove it today, oil pressure spiked about a 1/2 mile away, and the truck died at a stop light. I tried to crank it and it turned over, but wouldn't catch. I gave it a little gas and could tell it was trying to catch. I let it sit for 5-10 minutes, tried to crank it and floored the gas at the same time. It fired up and I drove it the rest of the way to work (6 miles) with the oil pressure staying at normal.

What's going on?


Avatar
Salkie
December 9, 2010.



I also replaced the air filter and the PCV Breather. Below are pictures of the inside of the valve cover and the old PCV Breather.


Tiny
Salkie
Dec 9, 2010.
The mustard stuff is water. If you just have that little bit on the valve cover and in the oil cap, it's from condensation and is nothing to worry about.

Cant say about the oil pressure spiking and the truck dying out. Report back if it happens again.


Buddycraigg
Dec 9, 2010.
Insure your PCV system is "SEALED" and actually S. UCKING air from the valve cover and if you put your finger over the Fresh air hose (other end of the cover) you feel suction there from the PCV action

On my Jeep if I seal it with my finger, my engine begins to run rough (because I'm interfering with air/fuel mix at idle) I have very little "Blow-By" from my rings----My Grommets seal the cover well. My rebuilt engine is over 8 years old, driven daily (AMC 258 6 cyl)

The PCV removes harmful gases and vapors from the crankcase, if it's not working correctly, it cannot!

The Medic

Here's some pics of my valve cover (PCV System)


Tiny
CJ MEDEVAC
Jan 9, 2011.
Did you try that yet?


Buddycraigg
Mar 1, 2011.
Oil pressure is still up and down. However, the PCV valve is good and is sucking air.

Recently, the transmission (4 speed automatic) has been shifting into 4th gear early. I'm changing the filter, fluid, and plan to add a transmission add in to insure that it is ok.

Wouldn't this cause my pressure to go up?


Tiny
Salkie
Mar 3, 2011.
NEGATIVE, OIL PRESSURE IS AN ENGINE ONLY ISSUE. THIS A CARB OR THROTTLE BODY FUEL INJECTION?

THINGS THAT MAY AFFECT OIL PRESSURE

1) ENGINE WEAR (INCLUDES OIL PUMP)

2) OIL YOU USE (OIL STABILIZER MY HELP)

3) OIL SENDING UNIT OR BAD GAUGE (VERIFY YOUR OIL PRESSURE WITH A MECHANICAL OIL PRESSURE GAUGE, EVEN AN "ADD ON" TYPE GAUGE, WITH A PLASTIC TUBE, CAN BE RUN THRU YOUR WINDOW TEMPORARILY, TO BE ABLE TO OBSERVE IT, WHILE DRIVING)-

AS FAR AS THE BLOWBY, A FULL TUNE-UP, AND DO A COMPRESSION TEST YOUR CYLINDERS.

IN MY PICS ABOVE, I CAN PULL THE FRESH AIR TO PCV COMPLETELY OUT AND SHOVE MY FINGER IN THE HOLE, THE PCV AT THE OTHER END OF THE VALVE COVER IS STILL IN PLACE AND S. UCKING. IT PULLS A GOOD SUCTION ON MY FINGER AND INSIDE THE ENGINE, AFTER 30 SECONDS OR SO, I AM DEPRIVING MY CARB OF SO MUCH AIR IT BEGINS TO RUN ROUGH. WHEN I SNATCH MY FINGER OUT, A REALLY BIG WHOOSH OF AIR REPLACES THE AIR THAT WAS S. UCKED OUT (IT IS VERY AUDIBLE).I CONSIDER THIS, LITTLE BLOWBY AND A GOOD PCV SYSTEM!

THE MEDIC


Tiny
CJ MEDEVAC
Mar 3, 2011.