# oil pressure problem



## OntarioGuy (Jan 5, 2011)

I got a 1997 f150 4.2 v6, its just my daily driver not really a work truck and when im driving the oil gauge is fine but after driving it for a while, when its warm and i come to a stop the oil pressure gauge starts to go up and down.
It only does it when its warm.
When no throtle is applied. 
There is no noise coming from the motor that should not be there.
Im just wondering what it could be? I read about the sending unit and stuff but i dont think its that, So im just wondering if its somthing i should be watching or if its just something thats nothing to worrie about.
Thanks


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## MickiRig1 (Dec 5, 2003)

How many miles on it? Change oil filter lately? Could be clogged and the bypass is kicking in.


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## OntarioGuy (Jan 5, 2011)

there is 364 xxx KMS on it, but the sensor that does the odometer is jumping and changes at differnt paces.
I did just do a oil change in the fall, it should get one done soon. I put lucas oil stop leak in there to help with a oil leak.


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## dieselss (Jan 3, 2008)

well only real way to rule out anything is put a gauge on it and see if it jives with the dash gauge
why do you not think its the sending unit??
if your speedo is jumping as well as gauge,,,,might be cluster related


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## OntarioGuy (Jan 5, 2011)

My speedometer got stuck at 0 a couple times, slap the glass infront and it will work.

How do you put a differnt gauge on to read the pressure? like is it kinda plug and play to get a more accurate reading?
I thought if it was the oil sending unit i would have the problem all the time. I could be wroung.
Thanks for your help guy.


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## MickiRig1 (Dec 5, 2003)

Most times the dash gage does not have a problem. If it really bothers you change the sending unit on the engine. How much does in move? Big swings or you just see it move a little? What is the MILES on it? I am a dumb American I don't know your measure of distance.


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## dieselss (Jan 3, 2008)

You have to put on a testing gauge...mechanical screw in gauge. Used just for testing 
What if the internals of the sending unit are on the fritz and only act up when they get hot ?


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## OntarioGuy (Jan 5, 2011)

226.1791 miles, i belive, i m bad at conversions. 
It does not bother me, i just what to make sure its nothing major. Its normaly in the middle of the gauge then when i stop it moves up to about 3 1/4 up and down to just above the red., i think once it went to the red.
But when its doing this the engine runs fine, no nosies or anything.


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## dieselss (Jan 3, 2008)

Is prob say sending unit. But get it tested


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## OntarioGuy (Jan 5, 2011)

Ok, so testing it would it be something i can do at home? (if i get the mechanical gauge)
THanks for your help guys. Ive never done much with the oil system, other than oil change and seals.


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## fordrulz (May 5, 2013)

You need to remove the sending unit near the oil filter and install a manual guage
in it's place than check the pressure when the engine is hot. Good luck!


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## OntarioGuy (Jan 5, 2011)

oh i see. ok, seams like somthing that if you screw up your getting burnt. lol
So if i dont replace it what could happen? like one day it just stops then no oil pressure? or will it give me notice.


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## fordrulz (May 5, 2013)

The oil pressure switch just lets you know if there is oil pressure but does not tell you how many psi. So if it is just a faulty sending unit and the oil pressure is actually ok there will be no issue other than a inop guage.replacing the sending unit is a easy fix though


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## OntarioGuy (Jan 5, 2011)

ok thanks, next oil change ill replace the sending unit. ill let yall know if it works.
Thanks so much for all your help!


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## damian (Jan 29, 2009)

just so you know the oil pressure guage on that truck is not really a guage,it is either reading zero or normal. it is operated by a switch,i believe over 8 psi switches on,under that and you get zero. that is why no ford truck past 1996 i believe will ever have a variable reading guage when accelerating or decelerating, cold or hot,they read either zero or normal. you may have a bum sender switch but you need to hook up a live guage to be sure.


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## OntarioGuy (Jan 5, 2011)

I new about the gauge before it gave me problems, thanks anyway damian.

So i did a oil change, i did not put the lucas oil stop leak in. I have the oil pressure sending switch but i could not get the old one out. it was so close to the oil filter head i could not even get a socket or a wrench (box or open) on there. also it looked really rusted, i did not want to strip it.

So after driving it around it seems like the pressure gauge is worse. But again no nosie from the engine.


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## fordrulz (May 5, 2013)

There is a special socket to fit the sending unit... Why not right can't be easy! Sounds like that is defiantly the problem though if there is no engine nose. Good luck!


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## OntarioGuy (Jan 5, 2011)

ya thats what i thoght. next time there on sale at princess auto ill pick them up. 
Stuiped question, i think i know the answer, can you change the switch with out drain the oil? I dont think so but i could be wroung.


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## fordrulz (May 5, 2013)

There is a special socket to fit the sending unit... Why not right can't be easy! Sounds like that is defiantly the problem though if there is no engine nose. Good luck!


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## fordrulz (May 5, 2013)

No need to drain the oil you will only loose a small amount when removing the switch.


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## MickiRig1 (Dec 5, 2003)

Of course it needs a special socket. It's a FORD! That's why I have 5. 51/2,6,7,8,9,11,16,18,20 and 21 Metric wrench's and sockets. They love the MM axle nuts too. Don't forget the metric off size hex drives and external / internal trox too


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## 2COR517 (Oct 23, 2008)

I have all those wrenches & sockets and never work on Fords. In fact, I worked on my GMC yesterday and only used Metric tools. Except for the pry bar. That was SAE. 

I also have 8, 11, 16, 19, and 22mm pieces in both the SAE and metric drawers


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## peteo1 (Jul 4, 2011)

Nothing worse than a metric pry bar. Those things are completely useless.


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## 2COR517 (Oct 23, 2008)

I learned the hard way with Metric Vise-Grips.

The Metric adjustable wrenches seem OK though.


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## B&B (Nov 4, 2006)

Don't forget to throw a 9 mm adjustable screwdriver in there as well. Mulch of the late model stuff makes it almost a must on the caliper return springs


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## MickiRig1 (Dec 5, 2003)

Yes, it was a 9mm hex drive on the caliper bolts. I admit I had a brain fart. If I would of spent 5 minutes on the Internet I would of had my answer! I have a brand new never used 3/8's x 3/8's hex drive on my desk by computer. It reminds me that it's a 9mm I needed!


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## basher (Nov 13, 2004)

2COR517;1637117 said:


> I have all those wrenches & sockets and never work on Fords. In fact, I worked on my GMC yesterday and only used Metric tools. Except for the pry bar. That was SAE.
> 
> I also have 8, 11, 16, 19, and 22mm pieces in both the SAE and metric drawers


No 24mm??? how do you tighten the eyebolts for the springs on snowplows?


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## B&B (Nov 4, 2006)

basher;1637172 said:


> No 24mm??? how do you tighten the eyebolts for the springs on snowplows?


A pipe wrench, how else.


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## 2COR517 (Oct 23, 2008)

No eye bolts on the springs up here. Can't hardly find a flop over plow...


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## basher (Nov 13, 2004)

B&B;1637173 said:


> A pipe wrench, how else.


SAE or Metric?


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## MickiRig1 (Dec 5, 2003)

I got all kinds of pipe wrenches. They never seem to be the right metric size.


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