lost oil pressure
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Joined: Feb 2004
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lost oil pressure
I have a 1989 F150, 95,000 miles that suddenly lost oil pressure while driving.
When cold, the oil pressure is fine and the engine runs great. after warmup of apx. 5 minutes, the oil pressure guage drops to 0, the check engine light comes on and the engine starts ticking and runs rough.
I have changed oil and filter, replaced the oil pump and front and rear seals.
I think I'm running out of inexpensive options.
What next?
When cold, the oil pressure is fine and the engine runs great. after warmup of apx. 5 minutes, the oil pressure guage drops to 0, the check engine light comes on and the engine starts ticking and runs rough.
I have changed oil and filter, replaced the oil pump and front and rear seals.
I think I'm running out of inexpensive options.
What next?
Senior User
Joined: Jul 2003
Posts: 423
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From: Nova Scotia, Canada
Time for some main/rod bearings by the sounds of it. My truck drops to about 10-15psi once its hot. I'll need some main/rod bearings soon too. My engine doesn't burn any oil so I'm just gonna drop the pan and roll some new ones in to get me a couple more years out of the 5.0.
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Joined: Dec 2003
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I had the exact same problem with my 93 F150. I am currently rebuilding my engine. A mechanic told me that if you drive on yhe interstate alot that the oil cooks under the intake before it has a chance to drain back down into the crankcase thus stopping up the oil galleys. I don't know how true it is but my engine was really gunked up and not getting enough oil.
Hope this helps.
Jeremy
Hope this helps.
Jeremy
Senior User
Joined: Jul 2003
Posts: 423
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From: Nova Scotia, Canada
Yes, but his engine is making noises so the sneding unit is likely not reading faulty. I have a manual oil pressure gauge in my truck. 50 psi at idle when first started, 15psi at idle once its hot. The bearings are toast, I'll roll some new ones in when I change my oil pan this spring. Its a shame too, the old thing works A-1!!
Senior User
Joined: Feb 2003
Posts: 341
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From: eastern Ma
Hello,
I had a problem like this one on an old 65 falcon. It turned out the previous owner jacked up the engine using a bottle jack, and no wood to distribute the force on the oil pan. The pan was pushed up in the middle, and pushed up the screen on the oil pump pick-up screen also. I pulled down the pick up tube coming from the oil pump, and banged out the dented pan with a hammer and 2x4. It actually worked. I think the engine was jacked up to change a motor mount. It might be worth a look at the pan..to check for dents on the bottom.
Plugged returns will cause oil pressure drop offs too.
Good luck
I had a problem like this one on an old 65 falcon. It turned out the previous owner jacked up the engine using a bottle jack, and no wood to distribute the force on the oil pan. The pan was pushed up in the middle, and pushed up the screen on the oil pump pick-up screen also. I pulled down the pick up tube coming from the oil pump, and banged out the dented pan with a hammer and 2x4. It actually worked. I think the engine was jacked up to change a motor mount. It might be worth a look at the pan..to check for dents on the bottom.
Plugged returns will cause oil pressure drop offs too.
Good luck
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Senior User
Joined: Dec 2000
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From: Sacramento, CA
"I'll need some main/rod bearings soon too. My engine doesn't burn any oil so I'm just gonna drop the pan and roll some new ones "
Can you replace those from underneath??
Can you replace those from underneath??
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Senior User
Joined: Jul 2003
Posts: 423
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From: Nova Scotia, Canada
I haven't tried it in this chassis, but I don't see why I can't do it this way. I've done it this way in bulldozers and higway rig's with no problem, its actually standard practice in both unless there was a major failure.
Senior User
Joined: Feb 2003
Posts: 341
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From: eastern Ma
J,
I missed some of your post, my fault, missed the part about changing the pump already. Please disregard my post.
You can change the bearings from underneith. Get some plastigage with the new bearings to check the clearance.
If you live in a warm climate or have a block heater, you might buy a little more time by going with a thicker oil.
The tear down or used engine is probably in your future though.
Good luck!!
I missed some of your post, my fault, missed the part about changing the pump already. Please disregard my post.
You can change the bearings from underneith. Get some plastigage with the new bearings to check the clearance.
If you live in a warm climate or have a block heater, you might buy a little more time by going with a thicker oil.
The tear down or used engine is probably in your future though.
Good luck!!