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oil pump replacement options?

skipc

NAXJA Forum User
If I find my oil pressure is really low and it's not the gauge, and assuming I'm losing a lot of pressure through worn components, I'd like to replace the pump with a higher volume/pressure version to make up.

On some engines, there are optional pump versions for replacement. AZ doesn't seem to carry any. Are there higher flow/pressure versions for the 89 4.0 and where do you get them?

Thanks.
 
I'd just replace the old pump with another new OEM pump. If you install a high volume pump, I suggest you also fit a bigger oil pan to increase the oil capacity because the high volume pump will suck oil out of the pan at a faster rate. It won't give you a higher oil pressure though.
A high volume pump is only really needed if you keep the engine at sustained high rpm e.g. offroad racing.
 
If you look at the way an oil pump works it has gears that move the oil, in the Navy we called em IMO pumps [I Move Oil] the oil system has a bypass spring as part of the lube system. This part is no kidding, those types of pumps are capable of over 5,000lbs, no typo Five THOUSAND pounds, to move more oil you make the gears wider to increase it's volume. Similar pumps are used on the hydraulics systems on submarines with accumulators that store the oil at the desired pressure, used for rudder, sternplanes, fairwater planes and other hydraulic systems. If you have low pressure you have worn bearings, crummy oil filter or the bypass system is shot, it is usually the mains but could also be the rod bearings. The best way to fix this is to put new bearings in of the correct size. When you do this it's also a good idea to do the pump too seeing as how you have it out anway, just remember to pack the pump with vasoline before putting it back in. Just my .02...
The crummy oil filter part allows the oil to pass thru too quickly, the pumps volume can't keep up and the pressure drops. There are differences between brands, Mobil-1, K&N, Mopar all give me different readings on my 98XJ. So far I have stuck with Mobil-1's.
 
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