Well that was quite a learning experience.
I have been using a FRAM filter for many years but have no idea if they contain the TWO check valves.

(...gee with all this new info I am getting I am afraid my brain may explode!! LOL)

Eric

I didn't know that either, TWO check valves....

This topic should be archived I reckon as this could affect many of us... some without knowing.

Thanks for leting us know the conclusion.

HI JAMES JUST TO ELABORATE ON THE FILTER VLVING A BIT AS YOU KNOW MOST ALL OIL FILTERS NO MATTER WHO MAKES THEM HAS A VLV THAT IS SUPPOSSED TO BYPASS IF THE FILTER STARTS TO GET PLUGGED UP, ALSO THERE IS OR CAN BE DEPENDING ON THE FILTER MANUFACTURER ANOTHER VLV IN THE TOP OR OPPOSITE END OF WHERE THE FILTER SCREWS ON, A SMALL VLV IN THERE IS USED TO PREVENT DRAIN BACK , SOMETIME WHEN YOU CAN , TAKE A FLASHLITE AND SHINE IT DONW IN THE OIL FILTER TO THE TOP AND IF YOU SEE A LITTLE STRAP OF METAL THAT STICKE UP ABOUT 1/2 TO 5/8 INCH IT LOOKS MORE LIKE A MIDGET HORSESHOE WITH THE ENDS WELDED TO THE CAN AND SOMTIME YOU CAN SEE THE SPRING FOR THE VLV RIGHT AT THE EDGES OF THE SMALL STRAP , THIS IS THE ANTIDRAIN BACK VLV AND A LOT OF FILTERS DON,T HAVE THEM, USUALLY IF THE FILTER IS SCREWED ONTO THE ENG HANGING STRAIGHT DOWN OR ON A SLIGHT INCLINE THEY WON,T DRAIN COMPLETELY WHEN THE PRESSURE IS TAKEN AWAY SO THEY FILL UP PRETTY QUICK THIS WAY , BUT IN THE CASE OF MOST ISUZU DSL THE FILTER IS UPSIDE DOWN SO , IF YOU HAVE HAVE A VLV IN IT IT WILL DRAIN DOWN WHEN THE ENG IS SHUT OFF AND IT MAY TAKE A COUPLE OF SECONDS TO FILL,, AS I WAS TELLING SPENCER WHEN YOU GET READY TO CHANGE THE OIL ON ONE OF THESE IF YOU WILL TAKE A LONG SCREWDRIVER AND PUNCH A HOLE IN THE TOP OF THE FILTER OVER CLOSE TO THE SIDE IT WILL LET THE FILTER DRAIN MUCH MORE QUICKLY AND NOT MAKE AS MUCH OF A MESS WHEN YOU UNSCREW IT WISH WE HAD SOME OF YOUR DSL S HERE , I WOULD NEVER USE ANY FILTER WITHOUT THE DRAIN BACK VLV WEATHER THE ENG NEEDED IT OR NOT , BUT A LOT OF THE AFTERMARKET ONES DON,T USE THEM JERRY

Thanks for jumping in Jerry, I appreciate it. I knew I wasn't doing a very good job of explaining it and I was hoping you would clarify.

Afetr a few hundred miles I can say confidently that the filter is absolutely 100% the fix. The engine no longer takes any more than a second to turn off the idiot light and to start registering oil pressure. Also, driving oil pressure is a tiny bit higher and I swear the engine sounds a tad quiter. That may just be me listening too hard though <img src="/forums/images/graemlins/smile.gif" alt="" />

Also, I have been meaning to clarify something for everyone: I said it didn't exhibit the symptom when cold. After we discussed it a few times, I double checked because as you folks pointed out, it didn't make sense regardless of the cause. Well, it appears I originally wasn't looking close enough because it did exhibit the symptom, just on a smaller scale. When cold, the light stayed on maybe 2-5 seconds instead of 4-6. The only time the light would turn off immediately is when the engine had been off less than 20-30 minutes.

I second the nomination for the archives too.

NCDiesel

I have just purchased a 1998 Wizard and they have done away with the oil pressure guage, I have to trust the computor to moniter that now.

It wont start unless there is a minimum pressure anyway.

just a thought with the oil prob you are having, have you changed the viscosity range at all? On mine it recomends 5w30 which is getting very thin when hot but older motors need a minimum of 10 at the bottom end of the scale, even 20 is common.

cheers

NCDiesel & All --

Well, I rummaged around in my trash can and found a genuine Isuzu oil filter from an '84 diesel P'up. I think these are the same as used on the Trooper TD. I cut it open and found that there are no valves inside other than the rubber flapper check valve for the inlet ports.

But this is a dual filter:

-- A normal full flow filter which filters most of the oil from the pump and delivers it to the oil gallery.

-- And a 'bypass' filter which filters a small part of the pump output through a very fine filter and delivers it through a small ( .028" d ) orifice back to the crankcase.The orifice is in the cast aluminum filter base. See my earlier photo of the base as I am adding an arrow to show where the orifice is located.

OK, the O-ring. This used to seal the full flow filter outlet from the bypass filter outlet. If it is missing, I think that air from the crankcase would flow up through the orifice to the bypass filter outlet and 'leak' (without the O-ring) to the full flow filter outlet and so allow the oil to drain back down through the pump to the crankcase. Hot oil would drain faster.

I have two photos:





NC's post of the oil flow chart for the TD supports what I have described except for the .028" orifice which is not shown. Unfortunately, this image was converted to a link which brings up the timing for a John Deere Model A tractor.
Randii??

I realize that what I have here is not the same as what others have said in previous posts so feel free to respond.

And, the oil cooler is a stand alone device as far as the coolant is concerned and can be separated from the oil filter base without coolant loss.

Paul

Sorry for the delay in replying, I have been away from my computer about 14 hours a day for the last two weeks and just can't seem to get any time on it to keep up with the posts.

First, thanks for the great post. Jerry did mention two check valves - could there be an anti-reversing design or maybe an actual valve between the full flow and by-pass parts of the filter?? Just wondering.

The lack of an o-ring must have been my culprit. The smaller neck in the filter probably didn't help much either.

Great post - I really enjoyed it and learned alot! Thanks again,

NCDiesel

NCDiesel--

Thanks for the response to my post. If there is another valve in the filter I sure cannot find it. I just went out to my shop and cut through the full flow section with a bandsaw to make certain that I wasn't missing anything. But the rubber flapper valve is all there is.

There is the possibility that our filters are different so maybe you could cut yours open next time you change a filter. It's a little messy to do but it is worth the trouble to see what is in there.

Regards--

Paul

hi paul and spencer that is really interesting on those filters not having the antisiphoning vlv in them , i have never cut one open myself , but was allways told by the japaneze people we dealt with that they did have them to prevent the exact problem that spencer was having , as they tended to bleed down sometime when the eng was shut off,, now the weird part we will have to get spencer to do this one , first paul is the filters you are using from isuzu silver in color , if so these are the filters that are supplied to the parts dirtribution supply , the filters that i got for spencer are the same filter that was used only for original assembyline installation, when the engs were new , and they are a bluish green , do they have the antidrain back vlv , i really don,t know ,i know they are suppossed to , i hope to find out , i sorta stumbled on a supplier of these accidently , why were they diff, in color , was so that in case of eng failure during the warrenty period, and after the milage interval that they were suppossed to be changed . if they were still the blue filter, you just could have had a problem with the warrenty people as this particular filter was not made available for parts distribution, this filter seems to be a bit heavier than the silver one, maybe imagination ,have not weighed one , would like to know for sure on the blue filter , so Spencer it is your turn to cut one open , i don,t have the heart to cut a new one , oh if you need any more i got 6 more in the other day along with the fuel filters Jerry

Jerry and Spencer--

Well, you can see from the image I posted that the filter I cut open has a blue like color, so may be the same as yours. Truth is, I was given this filter along with an oil cooler and base so I don't know it's origin.

I am not using this type filter on my engines any more as I am too cheap to buy them. I have converted both of my C223's and my son's to use the filter from a VW diesel which is about $5. It has only the full flow filter and is probably not as good as the Isuzu unit. I change the oil & filter every 3000 miles.

The VW filter does have a second valve inside opposite the threaded end. It is a pressure operated filter bypass valve, put there (I presume) in case the filter might get plugged up.

Worth noting here is that the earlier Isuzu engines (about '82 and before) used filters very similar to the VW filter.
I think they added the bypass filter when they added EGR to the engine.

Yeah, I wouldn't cut open a new one either.

Paul <img src="/forums/images/graemlins/cheers.gif" alt="" />