Oil leak at fuel pump

[andrew honychurch]

ok, so here goes, fist the photos then the explanation





in the top photo this is the set up as the vehicle came from the British Army, as far as I know. I have not altered it and the soldered seal on the pressure relief valve was stamped with an inspectors mark. It would appear to me, that the British, or a later Ford modification, has directed the oil relief flow to the point above the fuel pump as you can see in the photo. It is this oil flow, that I believe is finding its way into the fuel pump and flowing out of the petrol relief hole.

The set up as seen in the photo from the TM is quite different. It would appear that the relief valve is on the other side of the two pipes to mine. In other words either the pick up pipe has been changed on my engine, about 12 months later than the date of the TM, or it has been muddled by British Army when they made this mod.

So in the TM photo, it would appear that the pipe nearest in the photo is the return to the engine and the outlet pipe to the oil cooler has the oil pressure gauge and the relief valve attached to it. I assume if there is a restriction in this circuit it returns through the brass interconnection back to the return into the crankcase.

On my engine , you will see that my pressure gauge and relief valve are on the other pipe and the relief has been redirected to the oil filler pipe.

It may well be that I have followed the schematic in the TM ( another diagram not illustrated here) and connected the pipes on the flexible section of the oil cooler lines the wrong way around. I can check this today, but it still does not explain why these pipes are completely different from the set up in the TM. Go figure, and if you can work it out, please let me know.

Meanwhile, I plan at some stage to remove both pipes and check which way the oil flows from my engine left or right pipe then I can connect the cooler pipes the right way around for sure.

[horsa]

Attached a shot of my oil cooler lines even though its a different setup. Yours appears to have a second breather on the driver side of the rear engine. I've got that part connected to the top of my differential and don't have another breather on the engine other than the one where the oil enters the engine at the fuel pump where you are having the leak.

From your routing, the by-pass is open and sending the oil to the upper line. It's leaking is probably related to either the engine having too much internal pressure or air is coming in from the second breather and exiting from the higher original factory one and causing issues with the oil trying to flow inward against it.

Not real sure what the purpose of the alternate oil route would be since I've never seen that on another vehicle so far. If it was providing essential oil, they wouldn't have made it only functional when the valve was in by-pass mode.

Can you open the lines up front and confirm that oil will flow from the oil cooler lines? Or do you have the oil cooler shut off by manual lever if still installed? I don't have the levers on mine so can't turn them off if I wanted to.

[rob love]

I believe that the reason for the bypass was to protect the engine in the event of a plugged oil filter or crimped cooler line. If that situation occurred then it would simply bypass the cooler/oil system and still lubricate the engine. Your system would not do that. Rather the oil would just dump through the filler/breather tube back into the pan, doing nothing for the bearings.

Is there any chance your filter or cooler lines are partially blocked? Can you get a mechanical oil gauge on the return side, just before the engine, and confirm what the oil pressure is coming back into the engine?

80 psi at the relief would indicate to me that there is a flow problem either coming back to the engine. The flatheads generally would not generate that much pressure.

[Michael R.]

Could a faulty spring or adjustment in the oil relief valve also contribute to the high oil pressure?

[rob love]

You are right Micheal. The relief valve in the block (front of the valve gallery, ford group 6666) should regulate the oil pressure to about 30 psi or so. I can't seem to find the answer right away as to whether the oil relief valve comes into play after the oil exits the engine through the cooler/filter and then back into the engine, or if it regulates it before the oil leaves the block. If it is after, then the problem could still be with a filtration/cooler blockage. Does anyone have a good illustration of the path of flow on a Flathead lubrication system?

Adjustment or repair of the relief requires the removal of the intake manifold.

[Richard Farrant]

Hi Andrew,

From what you were telling me when we met yesterday, I have worked out a possible explanation. The oil will not flow to the cooler if it is cold, it will lift the relief valve in the remote valve block and return to sump, via dipstick tube. This might explain why when you drove the carrier, it did not show signs of leaking through the lift pump hole under the diaphragm, as it was hot oil and not flowing back via the tube. If I could find my T16 book I might be more sure but looking at a Windsor book at present.

[andrew honychurch]

Originally Posted by Richard Farrant

Hi Andrew,

From what you were telling me when we met yesterday, I have worked out a possible explanation. The oil will not flow to the cooler if it is cold, it will lift the relief valve in the remote valve block and return to sump, via dipstick tube. This might explain why when you drove the carrier, it did not show signs of leaking through the lift pump hole under the diaphragm, as it was hot oil and not flowing back via the tube. If I could find my T16 book I might be more sure but looking at a Windsor book at present.

thanks Richard. It has been very hot since the leak started so I think either the thermostat in the cooler has stuck, and reduced the flow causing the relief valve to operate, or as mentioned in my last post maybe I followed the schematic and hooked up the cooler pipe correct for the TM diagram, but the wrong way for my system which as you can see it exactly the oppostite way around.

Very odd!! On top of the Dingo playing up, I am not having a good few days!

[andrew honychurch]

Originally Posted by horsa

Attached a shot of my oil cooler lines even though its a different setup. Yours appears to have a second breather on the driver side of the rear engine. I've got that part connected to the top of my differential and don't have another breather on the engine other than the one where the oil enters the engine at the fuel pump where you are having the leak.

From your routing, the by-pass is open and sending the oil to the upper line. It's leaking is probably related to either the engine having too much internal pressure or air is coming in from the second breather and exiting from the higher original factory one and causing issues with the oil trying to flow inward against it.

Not real sure what the purpose of the alternate oil route would be since I've never seen that on another vehicle so far. If it was providing essential oil, they wouldn't have made it only functional when the valve was in by-pass mode.

Can you open the lines up front and confirm that oil will flow from the oil cooler lines? Or do you have the oil cooler shut off by manual lever if still installed? I don't have the levers on mine so can't turn them off if I wanted to.

Which extra breather are you referring to David? I have the breather in the usual place above the fuel pump and thats it. I do have two pipe elbows on the crankcase as you do.

I have not had any opportunity to look at it today, as we have been watching Olympics...family things. But will check this all out tomorrow.

One thing to bear in mind is that this oil was not pouring out on the 20 mile road run. Maybe the oil cooler has fouled up and is causing a restriction. Although I have blown air through and it pushes oil back out pretty easily.

I really appreciate ALL your help and ideas. I will report back asap when I have got to look at it in more detail.

ps David, no taps on the later oil coolers to shut off supply.

[andrew honychurch]

To be clear I thought I would just summarise the issue

1. My set up appear to have the oil pressure and relief valve on the other elbow to the book and David Gordons. This is odd as I assume only one of these elbows flows pumped oil out, the other is a return.

2. Which elbow flow oil out?

3. Did the arrangement of these oil pick ups change for some reason?

4. If mine is taking oil from the wrong elbow it will be sending it back in against the oil trying to flow out?

5. If I have followed the schematic when I hooked up the cooler lines, I may well have got the oil flowing into the wrong union on the cooler. Could this be affecting my flow rate through the cooler, and causing the relief valve to operate and dump oil onto the fuel pump?

Hope thats all clear thanks A

[rob love]

Originally Posted by andrew honychurch

To be clear I thought I would just summarise the issue

1. My set up appear to have the oil pressure and relief valve on the other elbow to the book and David Gordons. This is odd as I assume only one of these elbows flows pumped oil out, the other is a return.

2. Which elbow flow oil out?

3. Did the arrangement of these oil pick ups change for some reason?

4. If mine is taking oil from the wrong elbow it will be sending it back in against the oil trying to flow out?

5. If I have followed the schematic when I hooked up the cooler lines, I may well have got the oil flowing into the wrong union on the cooler. Could this be affecting my flow rate through the cooler, and causing the relief valve to operate and dump oil onto the fuel pump?

Hope thats all clear thanks A

Oil runs from the low one to the high one. It would seem the engine's oil relief is after the high one. Quickest thing you could do now is to put in an appropriate Tee fitting and hook a mechanical oil pressure gauge at the high one. If pressure at that point is 80, then your problem is going to be in the engine relief. If the pressure is significantly lower than 80, then you have a blockage or restriction in your cooler system.

[Lynn Eades]

From some U.C. books.

[Lynn Eades]

Of couse your system will be slightly different, so move with care.
Tony Smith is right, photos are better than me telling you.

The info regarding adjusting the valve is referring to ports marked the same as Michaels picture of the valve.

David that "breather' you have arrowed is the grease cup for the thrust bearing.