We knew it was time to deal with this oil pressure drop. There can be a few culprits causing it, but after a thorough examination, we determined that the most likely was the oil pump. Our first clue was the seeping from the mating surface between the oil filter adapter (a neck-like cast aluminum feature between the pump and filter) and the bottom of the oil pump housing that is integrated into the timing chain cover. This was merely an indication of the problem inside.

The oil pump housing and the oil filter adapter are both aluminum. However, the gears inside the oil pump hosing are steel. The bottom sides of the steel gears rotate against the top of the aluminum filter adapter. Eventually this creates a swirl pattern carved into the filter adapter. This gap (or tolerance) created underneath the bottoms of the steel gears and the aluminum surface they ride on can allow oil to bypass the gears and lower overall oil pressure. The gear teeth can also begin to wear and lose tolerance, which doesn't help keep up proper oil pressure.

There are several fixes: repair or replace the gouged up filter adapter; replace what may be worn-down oil pump gears; or use a steel midplate between the oil filter adapter and the oil pump housing to prevent the gears from cutting into the aluminum filter adapter again. Some don't like using a midplate because it means there are now two gaskets (one on each side of the steel midplate) through which leaks might occur, instead of the single gasket between the filter adapter and the oil pump housing.

However, the solution for us was the Bulltear Oil Filter Relocation Kit (PN 626). It meant we could do away with the scarred oil filter adapter completely and have a remote oil filter. The Bulltear kit includes an oil filter relocation end plate for the oil pump housing bottom. The end plate is a beautifully machined billet aluminum piece that retains the oil pressure bypass spring and plunger, and features two 1/2-14 NPT ports capable of flowing a -12 AN line. The kit also provides brass NPT fittings (two 90 degree and two straight), two 15-inch lengths of Parker 5/16-inch hose (PN 5139-10 WP) that is rated at 310 psi, and a remote oil filter adapter (PermaCool PN 1791). We wanted to mount the remote filter up in the engine compartment on the inner fender wheel, so we needed more than 15 inches of hose. Fortunately, we found all we wanted through the Parker Hose website, which directed us to its nearest distributor.

We also replaced the oil pump gears with a new set from BJs Off-Road and decided to go with the steel midplate as well. Even if you repair or replace the aluminum adapter, the steel gears are going to continue to eat at any aluminum part they ride on, and you are just going to have a pressure problem there again. The steel midplate and its gaskets came from Bulltear.

The entire job took about half a day, and it was fairly easy as go this sort of mechanical work and modifications. The end result is that we now have more oil in the system because the remote system adds oil capacity in the length of its hoses, the filter is up and out of the way so it's much easier to change oil and filters, and our oil pressure returned to a much more comfortable range. This was something that we were very happy to see.

1979 jeep sj 360 v8 oil pump rebuild seeping oil filter adapter lead

01This seeping oil filter adapter gasket was a problem we needed to fix. It led us to dealing with a low oil pressure problem we had wanted to take care of since we had acquired the 360ci V8-powered '79 Jeep Cherokee.