[AT] STP

[Steve W.]

Phil,
  I hate to be the bearer of bad news but if that F-150 is between a 
90-96 model you don't have an oil pressure gauge. You actually have a 
glorified idiot light. Ford decided that they were getting to many 
complaints about the oil pressure variations on there vehicles so they 
outfitted the 90-96 F 150, T-Bird and a couple others with gauges that 
don't read oil pressure, they read a resistor switched into the circuit 
by a switch in the sender.

What the manual says about the infamous OIL PRESSURE GAUGE!....

"When the engine oil pressure is normal, the oil pressure switch is 
closed(short circuit), allowing current flow through the 20-ohm resistor 
on the cluster flexible circuit into the gauge which drives the pointer 
to a position slightly above midscale.  The switch opens (open circuit) 
  when oil pressure drops to a critically low level (4.5 - 7.5 psi) 
causing movement of the pointer to or below the "L" band."

"NOTE: The pointer of the magnetic gauge will remain in it's last
position when the ignition is turned off.  It will move to the correct 
(or actual) indication whenever the ignition is turned back on."

http://groups.google.com/group/rec.autos.makers.ford.explorer/browse_thread/thread/46706ab95d9f44fe?q=ford+

This is for the Tbird but the F is about the same.

How to convert your oil pressure gauge
by Mike Maroschak
mmarosch at cgocable.net

1. Remove sender unit's wire.
2. Remove oil pressure sender unit with a 1 1/16" socket or the special 
oil pressure sender socket (which actually works better if you have one).
3. You might have to move some of the accessory belts out of your way.
4. Put Teflon tape on the new sender unit's threads.
5. You may have to use a 7/8" open ended wrench to **** the threaded 
pipe (that comes out of engine block) slightly one way or the other.
6. Thread in the new sender as tightly as you can with your bare hands 
(as you would your oil filter). It's easier if you make sure the sender 
and your hands are dry and grease free.
7. Re-connect sender unit's wire
8. A small number of Thunderbirds have the 20 ohm resistor located on 
the oil sender wire approximately 5 inches form the sender itself. If 
this is the case, bypass or remove this resistor and skip steps 8 
through 14 (inclusive).
9. Remove trim around instrument cluster. There are 2 screws at the top, 
then ease it on out.
10. Remove screws around instrument cluster. Ease it out several inches, 
tilt the bottom out, and gently pull the 2 connectors off.
11. Be careful not to scratch the instrument cluster's bezel.
12. Flip it up side down and solder a piece of 18 gauge (insulated) wire 
in parallel to the 20 ohm resistor behind the oil pressure gauge. There 
is no need to remove the resistor. Be careful not to melt the plastic.
13. This would be a good time to remove the bezel and clean it.
14. Also a good time to replace any burnt out bulbs.
15. Replace instrument cluster.
16. Remember to check for leaks.
18. When cold: between M and top line When hot at speed: M When hot in 
gear idle: between N and O When hot in park: O

19. The oil sender part numbers are as follows: Standard Motor Products: 
PS-60 Echlin: OP6091 Motorcraft: SW-1547-B, E4ZZ-9278-A


Phil Auten wrote:
> Ralph,
> Before you do anything else, try either a new sender or a new gauge. My 
> old F150 was showing low oil pressure too, and with over 200K on the 
> odometer, I thought it
> might be time for a new oil pump. I spoke with a couple of the mechanics 
> at the local dealership ( I used to work there) and they suggested a new 
> sender. I bought
> one in the parts dept. for about $10, and the pressure now shows above 
> the center of the gauge again, just like when I first bought it with 30K 
> on it.
> 
> Phil
> 
> At 12:00 PM 2/25/2007, you wrote:
>> Not sure if I may have asked this question before but I'm wondering 
>> again, how many , if any of you, use STP oil treatment in your old 
>> tractor engines? The reason I ask is that my Cockshutt 40 has lower 
>> oil pressure than I like to see. It seems to be gradually dropping as 
>> the years go by even though the engine is excellent and burns no oil. 
>> At full throttle running the snowblower it has oil pressure reading 
>> just on the line between normal and low. It used to be up in the o to 
>> r part of the word normal a few years ago. I don't know if the oil 
>> pump is wearing out or bearing clearances are increasing. I do regular 
>> oil and filter changes and have always used the same 10w-30 oil since 
>> the engine was rebuilt some 27 years ago.
>> I'm wondering if some of that good thick STP oil treatment might 
>> increase the oil pressure or at least provide improved lubrication to 
>> compensate for the lower oil pressure?
>> Just looking for opinions here.
>>
>> Ralph in Sask.
>> _______________________________________________
>> AT mailing list
>> http://www.antique-tractor.com/mailman/listinfo/at
> 
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> 

-- 
Steve W.
Near Cooperstown, New York

Pacifism - The theory that if they'd fed
Jeffrey Dahmer enough human flesh,
he'd have become a vegan.