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C12 oil pressure dipping below 10psi. Bought this engine,

but it in and have...
C12 oil pressure dipping below 10psi. Bought this engine, but it in and have not had any oil pressure since. Was told the motor had 161K on a fresh inframe. I have changed rods/mains, flushed engine, changed oil pump, and changed the filter housing. Is there anything else I am missing?
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Answered in 4 minutes by:
3/13/2017
Technician: Cat Man, Cat Engine Expert replied 5 years ago
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
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Thanks for asking your question. I will try and help you out.
Other than all the items you have replaced. The last two things I have seen cause low oil pressure is worn cam bearings or a piston cooling jet knocked off.
Please reply back if you need more help or have more questions. I am happy to assist.
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Customer reply replied 5 years ago
When I pulled the rod/mains I checked the cooling jets, they are all there. When I pulled the upper main bearing I had some coolant drop out. There wasn't coolant anywhere else in the engine that I could see.
Technician: Cat Man, Cat Engine Expert replied 5 years ago
Thanks for the information.
When you replaced the oil filter housing, did this include the relief valve as well?
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Customer reply replied 5 years ago
pulled all of them. No blockage was all clean.
Technician: Cat Man, Cat Engine Expert replied 5 years ago
Thanks for the information.
I have seen the relief valves over time stay open and cause low oil pressure. If the valve was not replaced. I would do so. They may look good but still be opening.
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Customer reply replied 5 years ago
Ok, I'll get those coming. Also, the oil pressure will start falling off after initial start and I've let it drop to 8 psi before I killed the truck.
Technician: Cat Man, Cat Engine Expert replied 5 years ago
If it falls off right after start up. That sounds like a relief open. Whenever I have a relief open I see this.
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Technician: Cat Man, Cat Engine Expert replied 5 years ago
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
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