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7.3 low oil pressure after engine is warm

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22K views 18 replies 9 participants last post by  JustinOOO9  
#1 ·
Ok guys for starters we got hosed on this truck. Bought this F350 with the 7.3. Heard nothing but good things about the 7.3. Made the buy. Got the truck home. Turbo started being loud. Figured it was due to the cold air intake. Next day truck under acceleration the turbo quit whining and copious amounts of white smoke. Great. Pull it over got a trailer and took it home. Got another turbo. Pre oil it put it on and fire her up. No issues. When the motor got warm it would lose oil pressure if the rpms got over 1000. What do I need to do from here. I'm learning as I go. I've not done anything to her just yet. Looking for ideals before I go working on her. Thanks in advance.
 
#2 ·
So first off. Your looking at the oil pressure gauge on the dash?

If so install a gauge in the port above the oil filter so you could see if it's the gauge or your having issues.
 
#4 ·
Yes as stated above you need to get something to scan and monitor what your numbers are and pull what codes have been stored,sounds like it's going into a "limp mode" or something of that sort
 
#5 ·
I will have to hook up a mechanical gauge to it. The previous owner was a liar so I'm not sure what he did to it. Not real happy with that guy. The oil pressure holds strong when the engine is cool. Only drops on the dash when it's warm and over 1000rpm. It will idle and hold pressure on the dash. I will check on the mechanical gauge and see what it shows.
 
#6 ·
I moved this thread to a more appropriate section. The thread will probably get a little more attention where it is now.
 
#7 ·
So just to let you know. The oil pressure gauge on the dash is just a switch. Anything over 7 psi it reads good. Under that it says its low.
 
#10 ·
Ok so got a mechanical gauge. My concern is this. How low can the oil pressure be and still be ok to run? At 2500 rps it is around 15psi on the mechanical gauge. At 2 it's around 20. Seems the higher the rpms go the lower the oil pressure goes. At an idle it hold at 20. At higher rpms the lowest it will go is 10 and hold steady. What could be the cause of that
 
#11 ·
What Oil filter is on it?? I know someone who had an issue after an oil/filter change was done. Problem was he could not build oil pressure, chased it down to a cheap oil filter ( not sure what brand but i can find out) . Swapped it out with a motor craft and problem solved. Might be worth checking.
 
#15 ·
Ok so I changed the oil in it. Put a motocraft filter on it which it already had but figured I'd change it anyway. Problem remains. My mechanical gauge is hooked up just above the filter so it's on the low pressure side. Cold start it runs 40psi warms up drops to 20psi for while but then levels off around 15. under acceleration drops to 10 and holds but the idiot light comes on and the gauge drops on the dash. I have looked and looked for this issue online but can't find it. There is still no smoke and the engine runs fine. Plenty of power I just don't trust it to pull anything other than itself until I can get the pressure where it should be. Any other suggestions before I take it to a shop and they start guess fixing it?