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Hummer Knowledge Base

The Hummer Knowledge Base

Engine/Oil/Dual Oil Filters:

Dual oil filters yield many benefits to our sooty diesel engines, it adds that extra quart of oil to the system, and adds that extra filter! The HMMWV's in Saudi had them installed due to the harsh sandy/dusty environment they operated in.

My truck is a 6.5L diesel, I don't know about other motors, so check before you buy.

Installation of the Gulf States (Saudi) Homologation kit (Dual Oil filtration kit):

Purchase the dual oil filter adapter kit, Surplus Enterprizes carries these (616) 651-3707.

Verify that you have:

  • Adapter
  • "O" ring
  • 2 reducers (those nipples you screw the oil filters on to)
You supply - 2 Oil filters (I use AC PF1218)

The special tools are:

  • Torque wrench
  • 1 3/8" (inch and three eights) socket; Sears carries these for 3/4" drive, so don't forget to buy an adapter to fit your existing set / torque wrench if you don't have a 3/4" drive socket set.

Here's how:

  1. Drain the Engine oil, and remove the oil filter (your doing an oil change, so make sure you have at least 2.5 gal of new oil!).

  2. You will have to move the drive shaft out of the way first, this will let you access the bolt that holds the old oil filter adapter on the engine block.

  3. Un-bolt the Center Bearing (That doughnut thing the drive shaft goes through thats attached to the engine mount with two bolts). Note the dirt shadows, (so you can put it back in the same exact place when you finish). Make sure you yell and scream a lot when you do this procedure. You may want to have the wife and any children in the area go away for a couple hours...

  4. Remove the 1 3/8" bolt retaining the old oil filter.

Installation of the new dual unit:

  1. Ensure the reducers are installed in the adapter (where the filters are going to get screwed onto).

  2. Lubricate the bolt (smaller "O" rings around the bolt) and adapter and insert the bolt (with all seals and washer in place) in the new dual adapter.

  3. Ensure the (new) "O" ring is in place.

  4. Install and bolt the adapter to the engine block (watch the "O" ring - don't let it slip out and get pinched!), tighten big bolt to 40 ft. lbs.

  5. Install the Oil Filters, pan plug, and fill crankcase to capacity, remembering that you now have to add 1 qt. extra than normal.

  6. Start the engine and watch the oil pressure. Check for leaks. Shutdown engine, Check oil level, adjust if necessary.

Don't forget to go back and re-forms the Center Bearing (drive shaft) and ensure it mounts in the exact same position it had been installed. Again, a lot of gnashing of teeth, yelling and screaming. It probably would have been easier if I removed the underbody protection. But, I did it anyway.

Got the Dual Oil kit yesterday. Dual Oil Kit includes:

2 Purolator oil filters
1 Dual filter adapter
1 connector
1 gasket
1 bolt
1 pipe plug 3/8-18
3 O-rings

Basically you remove the old filter adapter and install the new with new gaskets and such.

It will take an extra quart. And should be changed according to schedule. Having the dual oil filter system does not mean you can neglect changing your oil for longer than reccomended for one filter.

Dan Astrom

Earlier today, I assist Doug Zirkle with installing his Dual Oil Filter kit from AMG.

I know that there has been some interest on the list, so I took some pictures, and here they are...

Dave Breggin
'95 Diesel Wagon

AMG kit for dual oil filters. The Filter connector from the existing adapter is reused in the new installation. The bolt holding the adapter to the engine is not re-used.

The only difficult part of the installation is getting to the bolt holding the assembly to the engine. It is 1-3/8" (35mm) - a difficult size to find in 1/2" drive socket. (We finally used a 36mm socket.) We also had to detach the front drive shaft center support to allow the drive shaft to be moved enough to gain access to the bolt. The driveline protection did not have to be removed.

Parts.jpg - Parts contained in the kit

Fig1.jpg - Disassembly of Old Parts

Fig2.jpg - Assembly of New Parts

OldParts.jpg - Old Filter Adapter

Done.jpg - View of installed assembly

Dual Oil Filter kits are also available from Adventure Accessories

AM General supplies a dual oil filter kit for 1992-1998 HUMMERs the part number is 05744867 and can be purchased from your local dealer (like me!)


Martin Meissner
HUMMER Product Manager
Northwest HUMMER

>      has anyone installed the AMSOIL Dual Remote Oil Filter BMK-3R(Right) 
>      or BMK-3L(Left) BB100, or can anyone describe the oil circuit, the
> benefits, 
>      and drawbacks of the remote v.s. the factory dual system? 
>      Gerald, buddy?

Keri buddy, I am not familiar with the AMSOIL setup you mention. Dual filters are designed to filter a higher volume of oil. The filters are not sequential or of different types so the filtration is the same. However, if one gets clogged up or has higher resistance, the other filter takes more oil. Remote mounting the filter is usually a space/convenience thing or, as Dave mentions, adds an easy way to add a cooling loop if you didn't have one already. If the filters are finer than normal, the two filters can give better filtration. That is, if each filter has half the flow of an original filter and you have two filters now, you have the same flow rate (with possible higher pressure loss though) as the old single filter.

I don't really expect to see much with an extra quart of oil. Increasing the thermal mass by so little shouldn't affect oil temperature much. If you think about the overall picture, the engine introduces a certain amount of heat into the oil. The cooler dissipates a certain amount of heat. That's really all that matters. The oil acts like a capcitor and stores up excess heat that the cooler cannot dissipate right away. So if you have the same heat being absorbed by something with more thermal mass, its temperature will be lower. This is most beneficial for a system whose heat source (engine) varies the heat output frequently. In steady state, all that matters is ratio of cooling to heating. Oh, one thing to note is that the temp. of the oil is very important. The hotter the oil, the greater the temp difference with the air so it dissipates more heat than lower temp oil. Note too that the oil pan, lines, filters, etc all radiate heat. However, compared to a heat exchanger, I think the effects of having a second filter will be pretty low.


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