no oil pressure
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New User
Joined: Nov 2007
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no oil pressure
Rebuilt my 89 7.3 when out of the van turned over by hand and I had oil come out where the oil pressure switch. Put all back together in van starts and runs fine hooked up all wires no oil pressuer to gauge. took sender off put on mecanical on oil pressure. what did I miss?
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Did you use teflon tape on the sending unit threads?
With a one wire sending unit, the sending unit has to ground to the engine block.
The manual gauge is much better though.
Stock oil pressure gauges are basically idiot lights with pointer needles.
The reading really has no meaning as far as actual pressure changes.
With a one wire sending unit, the sending unit has to ground to the engine block.
The manual gauge is much better though.
Stock oil pressure gauges are basically idiot lights with pointer needles.
The reading really has no meaning as far as actual pressure changes.
Post Fiend
Joined: Oct 2007
Posts: 10,501
Likes: 5
From: Faibanks Ak.
If it moved oil turning the motor by hand apparantly the pump was working. Is it possible you have a kink in the line to your mechanical pump. I would first remove the fitting from the block and remove the wires from the pump and turn the motor with the starter and see if it shoots out of the block one or two turns should do it.
I know of at least one rebuild where a red rag was left in the pan and sucked into the screen closing it off another where a tube of silicone was left under the intake and after the motor warmed up the silicone ran out winding up in the screen.
I know of at least one rebuild where a red rag was left in the pan and sucked into the screen closing it off another where a tube of silicone was left under the intake and after the motor warmed up the silicone ran out winding up in the screen.
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
I did that to a Blazer, Told the guy I was R&R Rebuilds for to not let it go that I had left a tube in it and would be back the next night to pull the intake ... I showed up the next eve and he let the customer take the Blazer, tried telling me it was no big deal! That was the last job I did for him and last time we talked!
-Enjoy
fh : )_~
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Post Fiend
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From: Faibanks Ak.
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Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
I have seen engines rebuilt where to much silicone was used on the gaskets.
The excess that squeezes out on the inside of the mating surfaces gets washed off after a while and then winds up on the oil pickup screen.
Consider the oil path.
Pick up screen, through the oil pick up tube.
So either something is across the screen or the pick up tube gasket where it bolts to the oil pump could be leaking.
Then the gasket where the oil pump bolts to the engine could be leaking.
From there it goes through the block to the oil cooler front header, through the oil cooler bundle.
At the rear oil cooler header there is a pressure relief valve that returns excess pressure to the oil pan and the oil goes through the oil filter.
There is also a filter restriction bypass in the header.
From there the oil goes back into the engine oil gallery for distribution to the cam and main bearings.
I had low oil pressure on one of my reman engines.
A call to International revealed as little as 3 PSI was acceptable pressure at idle.
The excess that squeezes out on the inside of the mating surfaces gets washed off after a while and then winds up on the oil pickup screen.
Consider the oil path.
Pick up screen, through the oil pick up tube.
So either something is across the screen or the pick up tube gasket where it bolts to the oil pump could be leaking.
Then the gasket where the oil pump bolts to the engine could be leaking.
From there it goes through the block to the oil cooler front header, through the oil cooler bundle.
At the rear oil cooler header there is a pressure relief valve that returns excess pressure to the oil pan and the oil goes through the oil filter.
There is also a filter restriction bypass in the header.
From there the oil goes back into the engine oil gallery for distribution to the cam and main bearings.
I had low oil pressure on one of my reman engines.
A call to International revealed as little as 3 PSI was acceptable pressure at idle.