Ports Atop the Oil Filter - Pre or Post Filter?

[rbattelle]

This is something I've been trying to figure out for awhile. The reason I ask is I use Teflon tape for the fittings I've got in those ports and I'm paranoid of contaminating the oil system with bits of tape.



Any thoughts? I've attached two relevant figures from the Cummins ISBe manual. The first is showing a leaking oil cooler condition, but the important thing to notice is the flow arrows, which indicate to me that the ports are on the clean side of the filter.



The second shows the flow in a little more detail, and I can't decide whether it contradicts the first picture. (Note: device number 8 is the bypass valve).



Ryan

 

[Bertram65]

Hard to say, can't tell if the oil paths are next to each other or one over the the other, I have tephlon tape on mine, if it has not come off and done anything yet chances are it won't, I would think you would be at more risk of you removed it now, thought the risk is pretty small.

 

[jwilliams3]

Same path.

 

[Johnstra]

The regulator port has to be pre-filter. I suspect the other port is also pre-filter, but I don't know for sure.



I just installed my Gulfcoast O-1 bypass filter this weekend and I didn't use any teflon tape. I used a 12" section of grease gun hose to isolate my fittings from the filter head - I found that the vibration over time caused leaks when my fittings are attached directly to the filter head. The hose is 1/8 NPT brass and it appears to seal well all by itself.



-john

 

[Pawpaw]

The one on the right doesn't even look like what's on our trucks.



Here is the drawing from my '04 service manual. Based on that, I'd say there are two passages on top of the filter head. The lower one carries dirty oil into the filter, and the top one carries clean oil. The ports live on the clean side.



At least that's my take on it.

 

[rbattelle]

Yup, I think the ports are on the clean side now. Personally, I'd prefer they were on the dirty side.



I'd love to use something other than tape, but tape seems to work best for me.



Ryan

 

[Buffalo]

Aren't there liquid/paste type sealants that sould be used in motor oil/fuel conditions?



Joe F. (Buffalo)

 

[rbattelle]

Aren't there liquid/paste type sealants that sould be used in motor oil/fuel conditions?



Joe F. (Buffalo)

Yes, but Teflon tape has always worked best for me in terms of preventing leaks.

Ryan

 

[DavidC]

I use Permatex # 2. Never had a problem.



Dave

 

[RobertP]

all ports on top of the oil filter block are from the return side, so yes it is clean oil.

 

[WHazelwood]

I've been involved with hydraulic systems for over 30 years and never had a problem with the teflon on pipe threads, Just stay back one thread from the end when you wrap it.

Keep grinnin,

 

[AMassaro]

I use Permatex # 2. Never had a problem.



Dave

Is this Permatex #2 stuff black in color???

 

[DavidC]

Is this Permatex #2 stuff black in color???

Black or very dark brownish, non hardening.



Dave

 

[nickleinonen]

Black or very dark brownish, non hardening.



Dave

in the foil tube that always leaks from the back end. nasty stuff when it gets on your hands.



[the plugs are on the clean side. . ]

 

[DavidC]

in the foil tube that always leaks from the back end. nasty stuff when it gets on your hands.



[the plugs are on the clean side. . ]

It all comes with working on vehicles :-laf. Nothing any worse than gear oil,grease or used motor oil. I never wonder if a piece of the teflon tape came loose and is wandering around the system and it never leaks.



Dave

 

[AMassaro]

That's the stuff I've been using... just wanted to make sure.

 

[y-knot]

I stopded using teflon tape and any paste type pipe sealent several years ago. The systems on our trucks and other vehicals are just to important to trust to teflon tape. Oil systems and high pressure fuel injection systems are to expensive and sensitive to risk a piece of debra (tape) gettting in and ruining something. I have been using , with great sucsess, Blue LockTite. It sets up quick and has nothing to harm sensitive systems. I also manufacturere and sell High Performance Transmission coolers, and have never had a leaker, something un-heard of in the old Teflon Tape aera.

 

[amsoilman]

I've been installing By-pass oil filtes on these trucks for many years, and I use the ports on the top oif the OEM filter block for the "pressure" side of the by-pass. I "never" use teflon tape. The treads are "NPT", and don't really require anything to seal the threads. I've never had any leaks at these points.



Wayne

 

[rbattelle]

The treads are "NPT", and don't really require anything to seal the threads. I've never had any leaks at these points.

I very respectfully disagree, Wayne. NPT is not the same as NPTF, and is meant to be used with a sealer.



Personally, I've never encountered any NPT fitting that sealed without some agent. And I use mostly yellow brass. You must really crank down on 'em!



Ryan

 

[amsoilman]

I very respectfully disagree, Wayne. NPT is not the same as NPTF, and is meant to be used with a sealer.



Personally, I've never encountered any NPT fitting that sealed without some agent. And I use mostly yellow brass. You must really crank down on 'em!



Ryan

No, Ryan, I don't cinch them down real tight. But I didn't think the fittings we were talking about were NPTF type. I guess I just learned something new... ... that's what is nice about the TDR!



Wayne

amsoilman