does this sound right?
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Senior User
Joined: Jan 2000
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From: Massachusetts
does this sound right?
My truck recently acquired a new quirk: After reaching operating temp, at idle the oil pressure drops all the way down, while keeping it around 700rpm keeps the oil pressure steady in the normal range. I brought it to my mechanic to see if it needed a new oil pump. He said he's seen other ford motors with the same problem, and replacing the pump wasn't the fix. He said the other ford motors with the same problem were due to the main bearings failing, and the engine was losing oil pressure across the bearings. Does this sound right to anyone? The engine runs fine, and doesn't seem to make any strange noises when the oil pressure drops.
Elder User
Joined: Feb 2000
Posts: 601
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From: South Sioux City, NE USA
does this sound right?
I experienced the same problem with my '89 5.0L.
I replaced the oil pressure sending unit and the pressure now holds steady, no dips when the idle drops.
Roger Lane
Test Analyst
Sr. Automated Test Engineer
IBP, Inc.
I replaced the oil pressure sending unit and the pressure now holds steady, no dips when the idle drops.
Roger Lane
Test Analyst
Sr. Automated Test Engineer
IBP, Inc.
Thread Starter
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Senior User
Joined: Jan 2000
Posts: 361
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From: Massachusetts
does this sound right?
Kinda forgot to mention, it's a 351W from 85. Idles around 400-500rpm at stop lights and such. It just scares me because I was all set to have her painted, but now I don't know if I should spend the $2K if I'm going to have to replace the engine soon. Will it last more than a year or so? Anybody who's experienced this just give me a hint.
Junior User
Joined: Jan 2000
Posts: 57
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does this sound right?
>I experienced the same problem with
>my '89 5.0L.
>I replaced the oil pressure sending
>unit and the pressure now
>holds steady, no dips when
>the idle drops.
>
>Roger Lane
>Test Analyst
>Sr. Automated Test Engineer
>IBP, Inc.
I would start with the oil pressure sending unit like Roger. I had an 87 Ranger that did this. When cold or at cruise speed it was fine but warmed up at idle the oil pressure dropped to zero. Scared me to death as it started all of a sudden. This may not be your problem but it is a cheap thing to try and it may be the problem.
What happens is that the diaphram in the sending unit will develop a pinhole and allow the warm oil at a lower pressure to seep through and equalize the pressure on both sides.
Good Luck.
Eric B.
>my '89 5.0L.
>I replaced the oil pressure sending
>unit and the pressure now
>holds steady, no dips when
>the idle drops.
>
>Roger Lane
>Test Analyst
>Sr. Automated Test Engineer
>IBP, Inc.
I would start with the oil pressure sending unit like Roger. I had an 87 Ranger that did this. When cold or at cruise speed it was fine but warmed up at idle the oil pressure dropped to zero. Scared me to death as it started all of a sudden. This may not be your problem but it is a cheap thing to try and it may be the problem.
What happens is that the diaphram in the sending unit will develop a pinhole and allow the warm oil at a lower pressure to seep through and equalize the pressure on both sides.
Good Luck.
Eric B.
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Joined: Aug 2000
Posts: 4
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does this sound right?
Sounds right to me, had experienced the same thing in my Aerostar of all things. ALL (except for the front wheel drive cars)ford sending units are on the back of the block behind the intake manifold and are easily removed with a 9/16 wrench, Also put a bit of teflon tape around the threads in a clockwise direction being careful not to get any where it will plug the oil hole in the middle.
Foxxx
Foxxx
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Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
does this sound right?
[font size="1" color="#FF0000"]LAST EDITED ON 31-Aug-00 AT 02:54 AM (EST)[/font][p]Look at the drivers side of your engine. If it is a windsor engine (289, 302, 351W) then the sending unit should be located on the driver's side just above your oil filter. If you have a mechanical fuel pump, it should be above that also.
If it is a true sending unit, then you shouldn't need any special tools. But, if it is an oil pressure "switch" then you will probably need to pick up an Oil Pressure Switch Socket. Most auto parts stores have these. There is also no way to swap the two out (convert from a switch to a sender) or so I have been told.
Hope this helps.
If it is a true sending unit, then you shouldn't need any special tools. But, if it is an oil pressure "switch" then you will probably need to pick up an Oil Pressure Switch Socket. Most auto parts stores have these. There is also no way to swap the two out (convert from a switch to a sender) or so I have been told.
Hope this helps.
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