oil pressure
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oil pressure
Hey guys. Sorry if this is already answered, just couldn't find it. Hooked up a mechanical guage to check oil pressure. It reads about 10, and when I give it gas it drops down. Any Ideas?
Truck sat for years, changed the oil and it was very gunky. So I'm sure there is still some gunk in there that needs to be changed again. I have a new oil pump for it, and I am hoping that will be the answer.
85 f150 4.9l 4x4
Truck sat for years, changed the oil and it was very gunky. So I'm sure there is still some gunk in there that needs to be changed again. I have a new oil pump for it, and I am hoping that will be the answer.
85 f150 4.9l 4x4
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Is this a electric gauge or one with the little oil tube? And if it's electric it came with it's own sending unit correct?
P.S. Sorry, you said mechanical so I am going to assume it has the oil tube correct?
P.S. Sorry, you said mechanical so I am going to assume it has the oil tube correct?
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Joined: Apr 2011
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From: Orlando area
Typically low oil pressure is due to excessive bearing clearances (excessive from wear).
You could try a thicker oil (like 20-50).
I doubt the oil pump is worn out without the rest of the engine being worn out too.
10 psi for each 1000 rpm is acceptable.
Good luck
You could try a thicker oil (like 20-50).
I doubt the oil pump is worn out without the rest of the engine being worn out too.
10 psi for each 1000 rpm is acceptable.
Good luck
Fleet Mechanic
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So the oil pressure goes DOWN with increased engine RPM instead of UP? That's really weird!
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From: Orlando area
One thing that happens on these old engines - when owners "degunk" is that all the sludge that is loosened from the top end goes into the pan and clogs the pickup screen on the oil pump. Then when the rpm is increased your getting a sort of vacuum build and there is not enough oil entering to the pump to keep up with demand so you see a pressure drop.
Many will advise not to "degunk" and engine for this reason. At this pint you will have to drop the pan and clean everything by hand.
Many will advise not to "degunk" and engine for this reason. At this pint you will have to drop the pan and clean everything by hand.
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Sorry I haven't had anytime to even think about working on my truck. So I'm still stumped as to what to do? I already bought the oil pump, so I guess I should drop the pan try and clean out all of the gunk. Replace pump and screen. Was reading another good thread (should i keep it stock). seems like a clogged screen was his issue for oil pressure lowering. Im just not sure how deep into the engine I want to go since time and more importantly never have doing any of it before.
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It's a real pain to drop the pan while it's in the truck - but unless you want a large paper weight sitting in your driveway - you have no choice (or pay someone else to do it).
However if the engine is that "gunked up", you may be better off pulling it and replacing or rebuilding.
Pull the valve cover and see how nasty it looks.
However if the engine is that "gunked up", you may be better off pulling it and replacing or rebuilding.
Pull the valve cover and see how nasty it looks.
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From: W (BY GOD) V
As mentioned, dropping the pan and giving the engine a douche' (Fr.) is the only option (other than complete tear-down). Maybe run SEAFOAM or an oil flush in the engine before dropping the pan. The top end can be cleaned with varsol while the pan is off.
An oil pump will wear out like anything else. You can also remove a main cap at tear-down and plasti-gauge an insert to see the clearances. If when reassembled, the pressure is not within standard, you can turn a set of mains in if the journals are good.
An oil pump will wear out like anything else. You can also remove a main cap at tear-down and plasti-gauge an insert to see the clearances. If when reassembled, the pressure is not within standard, you can turn a set of mains in if the journals are good.
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