Oil pressure -

[FBA]

Curious as to what oil pressure is supposed to run around when cruising on the highway in 70 degree ambient temps (car warmed up). I see it runs around 55, but when I put my foot in it, she may drop around 5psi, before coming back up. I've seen it run up to 75 or so...but this drop in pressure has me wondering. I have oil dripping down from an under-body panel bolt in the rear on the passenger's side after a run...not much - but enough to see. I haven't removed the panel yet to see what's up...

 

[RALPHIE]

Curious as to what oil pressure is supposed to run around when cruising on the highway in 70 degree ambient temps (car warmed up). I see it runs around 55, but when I put my foot in it, she may drop around 5psi, before coming back up. I've seen it run up to 75 or so...but this drop in pressure has me wondering. I have oil dripping down from an under-body panel bolt in the rear on the passenger's side after a run...not much - but enough to see. I haven't removed the panel yet to see what's up...

Running pressures sound about right, but the drop to 5 psi would bother me too!! Maybe the oil pump belt is slipping when you're accelerating hard??

 

[MAD IN NC]

I have never seen it drop to 5# EVER. Mines runs about 60+ on startup and on the highway ~ 55#..

Could be anything like the sending unit or drive belt/ cam....

How many miles? When was the last time it was serviced for oil?

What filter was put in? a real FoMoCo/ Mann or a knock off?

 

[nota4re]

Hey FBA,

I wouldn't worry too much as I suspect the sending unit is the most likely suspect. Nevertheless, oil pressure issues do call for caution as the motor is a wee bit expensive.

Note that it is physically impossible for an oil pump belt to "slip". It is a geared belt with a "V" track pattern. Oil coming from the pan on the pass side is a little odd and also a little concerning as the oil pump is located immeditately behind the passenger seat. I would advise that when you have the opportunity to raise the car and remove the rear and mid pan, you do so and look for any drips coming from the oil pump belt cover. There is known, occasional failure of one of the pump seals and if you have it, you will notice some drips coming from this belt cover. Also, the belly pans provide a good means to determine how much oil is dripping and from where. If you get a chance to get some pics, some of us might be able to give you some further advice.

 

[2112]

I bet it is the sending unit too.

But, There was a thread about a oil pump pulley that had been R&R's incorrectly and became stripped out where it meets the shaft. I forgot who posted that, it was last summer or fall.

 

[paul b]

Try to identify the type of oil, maybe transmission

 

[standj]

The up and down oil pressure sure sounds like the sending unit, which may of us have had to replace. AS for the oil leak, I had to replace the actual oil pan and gasket, to solve a oil leak issue that I had almost from day one.

 

[FBA]

Sorry - if I wasn't clear, I was trying to say that it drops BY about 5psi, not TO 5 psi...so it drops to around 45-46 psi for a bit then comes back up...
I get my new wheels next week, so I'm heading to my buddy's shop to install them and the adjustable perches - and will have him take the pan down and check the pump area, or wherever the leak is coming from anyway. I'm not driving it till then anyway...

 

[PL510*Jeff]

Sorry - if I wasn't clear, I was trying to say that it drops BY about 5psi, not TO 5 psi...so it drops to around 45-46 psi for a bit then comes back up...

just a normal change. When really warm oil pressure may drop 40# to 15# at idle. Then as revs build pressure will build up to the 60-75.

Typical for a dry sump system.

 

[FBA]

So I'm clear - You're saying that it is normal when cruising down the highway in say 6th at about 70-75, if I put my foot in it, it is normal to drop a few PSI then come back up? I rarely see 60-75psi BTW...

 

[DWR46]

I have read all the comments with interest. However, what I believe FBA is describing is the crankshaft moving slightly in the block when the engine is put under additional throttle load. This normally occurs in engines that have some miles on them and some main bearing wear. In these situations, the oil pressure will drop 5-10 psi as the oil pump replenishs the the "gap" between the crank and the bearing caused by the crank moving slightly as the engine is loaded with more throttle opening. Once the "gap" (just a few thousandths of an inch) is filled with new oil, the pressure comes right back up and will continue to build as the revs rise and the oil pump is turned faster. This is not unusual at all, and I would not worry about it. How many miles are on the car? How has it been used? What were the main bearing clerances in this engine when it was buiilt? All of these questions will have an effect on the above situation. Obviously the greater the main bearing clearances, the more pronounced the oil pressure fluctuation will be when the engine is put under or taken off load.

 

[ViVa gt]

Curious as to what oil pressure is supposed to run around when cruising on the highway in 70 degree ambient temps (car warmed up). I see it runs around 55, but when I put my foot in it, she may drop around 5psi, before coming back up. I've seen it run up to 75 or so...but this drop in pressure has me wondering. I have oil dripping down from an under-body panel bolt in the rear on the passenger's side after a run...not much - but enough to see. I haven't removed the panel yet to see what's up...

don't know if this will help, but is a place to check. last summer after a few hard runs, i noticed a spotty fluid on the rear glass at the cockpit. i went to ford to have it inspected. the culprit was a bad seating of a o-ring at the breather housing. it was this way from the factory. previously we,the mechanic and i, noticed oil on the bellypan while doing an oil change. we assumed it was a messy oil change from the previous dealer that serviced the car.
ford change the seal and housing and no problem since.

 

[FBA]

Thanks for all the replies guys - I'll print this thread up and be sure to take it with me next week...I'm pretty sure it's minor..
@DWR46 - 2100 miles, and I don't believe the car was run hard before I got it...tires don't seem to indicate a lot of wear. No way for me to know what the clearances were either. I just know I don't see this type of behavior in any of my other vehicles.

 

[2112]

Let us know if you find anything out of the ordinary. :thumbsup

 

[FBA]

I will indeed!