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Pre Lube Oil Pump



oil pump mounted on frame rail My pump is installed on the passenger side front frame horn. The frame was drilled and tapped for 1/4-20 bolts.

oil filter spacer with filter installed    oil filter spacer and connection hose  oil pan adapter and pump feed hose

Oil Filter Spacer, spacer nut, and oil pan adapter
(Engine Lubrication Systems Preluber Kit Photo)

Update June 2, 1998:

In a letter to the TDR (#20 page 41),  Engine Lubrication systems states that the Pre-Luber is still in production and distributorship is growing.  Parts are available for Pre-Luber pumps.

Engine Lubrication Systems        (610)647-2417
64 State Road                               (610)647-0877   fax
Paoli, PA  19301                           mailto:enginelube@aol.com

Call (800) 647-7383 for ordering information or the location of the nearest Pre-Luber dealer.

Other Pre-lube Systems Available:
Bob Sullivan Restorations sells the Masterluber pump system.
SOS Automotive Specialties Co. sells the Pow-R-Lube reservoir system.

You can always build your own:  Build your own preluber -  posting from the Cummins mailing list


> Has anyone installed or have any comments about a pre-oiler? I've read good things about it.

I had held back until now because my pump failed. Now that I have dismantled the oil pump and discovered how it failed, I can give a few comments.

It is reassuring to be able to pressurize the oil lines before startup, especially in cold weather, after an oil change, or after the engine had been sitting for a week or two while I wandered in the woods. Without prelubrication, the engine oil pump normally takes 5 to 10 seconds to build pressure while the engine runs with NO pressure lubrication.

I like the convenience of the shutdown cycle, where the pump runs for several minutes after the key is switched off to cool a hot turbocharger .

My oil appears to remain clean longer after an oil change, perhaps because the shutdown cycle cools the engine and turbo bearings, and reduces oil breakdown just after the engine has stopped.

I enjoy mess-free oil changes because I can pump the oil filter full of air before removing it, and refill the filter with oil using the pump AFTER the filter is installed.


The adapter fitting on the bottom of the oil pan and the hose to the pump looks vulnerable for off-roading.  If the hose is ripped from the fitting while in deep water, the result could be catastrophic.

The pump's oil feed adapter between the engine and oil filter makes the filter hard to remove.

The original 30 Amp fuse on the pump would constantly blow in cold weather.

The original control box start-up cycle was too short in the winter, requiring repeated key cycling to get oil pressure.  NOTE: The new control boxes have a longer start cycle.

The original control box shut-down cycle would run the pump for the same fixed time, regardless of whether the engine had run for five seconds or five hours.

The pump is noisy when it is running.


After 36,000 miles and three years, worn brushes in the electric motor caused my pump to quit.

There is no grease seal between the gearbox and motor on my pump. I had mounted the pump vertically with the motor under the oil pump and, over time, the gear grease migrated through the motor bearing and collected at the lower end of the motor where the brushes were. The grease contaminated the brushes, causing them to stick in their holders. Once the brushes quit moving freely, they began to arc and wear.  Although the manufacturer claimed that the pump can be mounted in any position, the motor should not be placed below the gear case.

After cleaning the brush assembly, turning the commutator, and making new brushes, I reassembled and tested the pump. It ran as well as it had when new.


Despite the vulnerable appearance of the oil pan adapter, I have never experienced a clearance problem with it. I tried to keep the oil line tied as high as possible to prevent brush from grabbing it, installed a low oil pressure alarm, and carried the original oil pan plug and three gal of oil "just in case".

The extra 1.25" that the adapter added to the oil filter makes filter removal a challenge with the diesel because the AC lines run just beneath the oil filter. The adapter was an option which routes the pump output through the oil filter. Without it, the standard kit runs the pump output directly into the oil galley WITH NO FILTER. Sucking oil from the bottom of the oil pan and injecting it directly into the oil lines seemed to me to be an invitation to disaster.

The original Preluber control box and 30 Amp fuse were replaced with a home-brew controller and 40A circuit breaker, which gave me better control of the timing cycle and trouble free operation in cold weather. A manual switch is also a handy addition.

If you tend to drive for long periods with a few engine starts each day, this pump will probably not help you. If you have short trips with many start/stop cycles each day, you MAY extend your engine life (may is the key word here). The Cummins doesn't need much help in the engine life department because it will easily outlive the truck. For me, the pump is more of a convenience item.

UPDATE  Dec 25, 1999 - The gasket between the filter spacer and engine began leaking at a rate of about 1/2 qt per 3000 miles. This is not a significant oil leak, but it was messy to have oil dripping down the oil filter onto the front suspension and axle.

I could not find a replacement gasket, so I removed the old gasket from its groove, applied a bead of red RTV silicone rubber to the groove, and seated a gasket from a used oil filter into the groove. A flat weight was set on the gasket surface to keep it seated in the RTV. After the RTV had cured for an hour, the adapter was bolted back onto the engine and the leak has stopped.

Subject:    Pre luber installation.
Date:        Fri, 30 Jan 1998 18:00:18 -0800
From:      "Nigel J.P. Falls-Hand." <nigel@linkline.com>
To:          dfritz
   I mounted the pump on the front cross member below the radiator, oil pick up is from the sump plug device supplied. I knew that the filter adapter would be useless due to a.c. clearance so I did not order it. I asked the supplier to send a remote filter device but the request was not understood.   A T.D.R. reader had a letter published, indicating that he simply removed
the plug from the top of the filter housing adjacent to the turbo oil feed line and connected the oil return there, Not a good idea, as that plug feeds into the discharge side of the oil filter gallery. The writer unfortunately believes he is filtering his oil, whereas he is back-flushing his filter.

  I threw caution to the wind and drilled through the top of the filter housing into the inlet oil gallery (outer side), tapped a 1/8 pipe thread and screwed a fitting in. Despite no casting reinforcement at the location I drilled at, the casting was sufficiently thick, approx 1/4". I was careful not to wrench down the fitting to tight for fear of starting a crack.

  The ignition on line for the controller is connected to a harness connector at the bulkhead adjacent to the air filter. I do not know what the connector is for, it may be a diagnosis terminal. I think it disconnects at start position though, as my pump runs to long at start up.

  So.... all works ok except for the following gripes that maybe you can help me with.

Nigel Falls-Hand

Nigel J.P. Falls-Hand. wrote:

>   The ignition on line for the controller is connected to a harness
> connector at the bulkhead adjacent to the air filter. I do not know what
> the connector is for, it may be a diagnosis terminal.

It's the diagnostic connect for the engine computer, and I used the same connector for a while until I built my own pump timer.

> I think it disconnects at start position though, as my pump runs to long at start up.

Hmm, mine never ran after startup. In fact it usually quit to early in cold weather (no pressure) and took several cycles to pressurize. Moving the key to the start position would not trip the cool down cycle.
>   So.... all works ok except for the following gripes that maybe you can
>  help me with.

>   1.    Noise.  Despite using rubber mount blocks, the pump is so noisy I
> think it is defective. It fairly howls when running. Is this normal?

It's normally very noisy. I'd call it "wake the dead" noisy when used after bedtime. During the day, it's noisy enough to make people stop and look. I would not call it howling, which could indicate a pump bearing problem.

>   2.    Leaks.  The pump leaks around the case, not much but enough to be
> annoying.

Mine doesn't leak, and all of the older units I know about don't either. Another person recently e-mailed me complaining about a leaky case. Both of the leakers have come from Engine Guard, so maybe the gasket material is more porous than the older Sales Professionals version.

>   3.    Low pressure. On my oil gauge the pressure pumps to 35# with the
>  preluber. when engine runs I get 45#, I thought the preluber pumped at 55#?
>  Also, when the engine is hot, the preluber pressure never builds up
>  enough to give a gauge reading or turn off the oil warning light.

The Preluber has a 55# regulator, but the preluber has considerably less capacity than the engine oil pump. When the engine is cold, the preluber pump can move enough cold, thick oil to produce measurable pressure, and mine usually hits 45# cold. When the engine is hot, there is enough oil flow from the bearings and piston cooling nozzles to keep the oil pressure below the gauge's threshold. I was concerned that mine was not pumping when hot, so I pulled the plug from the top of the oil filter and it sprayed oil everywhere before I could get the plug back in. With my thumb, I guessed the pressure to be about 5psi.





Last Update July 25, 1999