Lost Oil Pressure Sending Unit


#1

The oil pressure gauge is dancing on my 4.2L '99 Ford E-150 (V-6) and at times the oil light comes on but there’s no rattling or other signs of oil deficiency in the engine. I’m pretty sure it’s a problem with the sending unit and did an oil change today but for the life of me couldn’t find where it’s located. I looked all around the filter when I replaced it but to no avail. The Haynes manual and internet pics I find are no help because there’s no recognizable parts in them to reference. I can’t tell if they’re looking under the car, on top, driver’s side etc. Please help.


#2

Go back to that manial again and look at the pictures one more time.

If the picture points out the battery, the PCV valve, the air cleaner …you’re most looking at the top view.

If the picture points out the oil filter, exhaust, the dead skunk carcas…you must be looking at the bottom.

It wouldn’t be by the oil filter, but maybe on the side of one head, in a top view picture.

Yosemite


#3

No, they’re all in too tight. That’s why I’m asking.


#4

It’s in the rear of the block, top right-hand (passenger) corner…Take the dog-house off and look around the top right-hand corner of the engine…It’s very close to the bell-housing flange…


#5

The manual says it’s located on the “left front of the block”. Is that the driver’s side or passenger’s side? I’m looking all over and can’t see anything familiar with what the pic is showing.


#6

The heads and intake manifold may cover it completely…Google “4.2L Ford V6 oil pressure sender” There are several pictures and diagrams posted…


#7

The manual says it’s located on the “left front of the block”. Is that the driver’s side or passenger’s side? I’m looking all over and can’t see anything familiar with what the pic is showing.


#8

Caddyman, I thought about that but the manual usually tells you if you must remove something in order to get to a part. Checking now…


#9

In the picture you posted, the transmission appears to be at the top of the picture, the edge of the bell-housing sticking up…On the right, a cylinder-head with a freeze-plug showing, the sender mounted on a right-angle extender/adapter…A heater hose on the left side…


#10

The hexagonal pipe that the sender is attached to is just above the oil pump. I thought the picture was quite obvious.


#11

The only thing I will add is that excessive wear can exist which can trigger the oil light due to low oil pressure and there may be no rattling or knocking at all.


#12

The gauge on most Ford light duty trucks since about 1990 have been “dummy” gauges. The sending unit in the picture is an oil pressure switch and cannot indicate fluctuating pressure when used with a gauge. Ford soldered a resistor into the gauge circuit and connected a sender(switch) that operates reverse to the switch used for dashes with only the OIL light. When 10 to 13 psi is reached the sender(switch) closes and grounds the wire to the dash and the gauge jumps up to indicate normal pressure but the gauge is as meaningless as having only the OIL light.

The Ford 4.2L V-6 is similar to the earlier RWD Buick 3.8L V-6 in that the oil pump is integral to the aluminum timing cover and driven by a gear attached at the camshaft timing gear. And like the Buick engine there were problems with the oil pumps and there are kits to repair them if the timing cover pump housing is not severely scored. Of course the entire front cover with a new oil pump can be installed.