I agree with Ray54. I would highly recommend you replace the O-rings and fix the diesel getting in the oil problem. It is not a difficult job. I am afraid you will regret it later if you choose not to do it. I did my D4 a few years back.

Bruce

Rome: Is this a common problem for the 315 engine? I ask, as I have encountered the same leaking/weeping from the same stud location on 2 formerly owned D4s and never gave it too much thought (although perplexed as well). Thanks, JM

I have not had this happen on any D4 I've had or worked on but since its #1 cylinder maybe it got too much horseradish on a cold morning and blew the gasket at one time, not sure. Or since being #1 cylinder it gets the hottest as being near the coolant outlet in the head. Just a thought.

remove the head and fit a new gasket coat it with a head gasket dressing before install to help it seal remember to check the head and the block for warping. if the head is warped it can be machined back to true.

while the head is off check the head for cracks, you can have it magna flux tested. or you can use dye check (flawcheck) which is a series of sprays that are applied in a set order and will highlight any cracks or flaws in metal castings and welds any good engine shop can do either test. flaw check can be done at home as it requires no special equipment the product is sold in kit form by most good industrial suppliers. it can be possible to fix cracked heads by stitch plugs or welding this is a pay for it to be done job as it isnt easy to do at home.

you can also use chemi-weld or metallic seal up. Nulon Oil company makes a head sealer that works very well. remember these products are only for use on cooling system leaks.

Updates:
1) Checked all fluids before starting and topped them off as well as smelled them for anymore fuel leaks or water etc.

2) Had to reprime the system as it would appear to have lost prime over winter via a small leak in the ball valve we put in, rather via the threads on the ball valve :/
I did take those threads apart and apply thread sealer to them and the leak stopped.

3) Machine ran, but I could tell there might still be a little air in the system at first, it seemed to work itself out after about 30 minutes of use. When I shut the machine down the idle timing sounded good.

4) Machine only ran for 30 minutes. At first it was pushing ok but then after a while it seemed to default to previous season issues where it can't push anything ... it was having trouble simply turning to get it to my parking spot... Last year I recall we changed fuel filters and that seemed to allow the machine to push 1/2 the load it could when we first got it but it didn't fully fix the issue. Really not sure what the problem is yet. Motor was not over heating, all levels seemed fine for fluids. Governor increased / decrease engine speed as expected. I will have to go back and reread my own thread to see what insights were previously suggested for this problem. 

5) Dike worked to stop the leaks. Just waited for the coolant to start flowing and added it right in since I knew the fluid level was good. Will see how it preforms on a restart soon.

bursitis wrote:

probably the o ring seal between the fuel tower and the injection pump. pretty sure it is a number 8 o ring that can be purchased just about anywhere. probably just as easy to fix the oring as to install a valve. and the valve won't prevent the oil from diluting anyway.

Where is this o-ring located? Looking at page 119 in the cat diesel engines book and I can only see seals labeled requiring you to take the injector housing off the machine. But given your response saying it is as easy as cutting a hose and attaching a ball valve I suspect it doesn't require removal of the injector housing. 

the injection pump housing has to be removed to fit the new seal. problem is if that seal is leaking the fuel will dilute the oil which will destroy the bearings and cause serious engine damage. yes the tap stops it leaking while its sitting but its still leaking when running over time it will create problems.

On the image on page 119 is it #2 toward the top?

I saw a video which showed an internal seal on the fuel tower toward the bottom which held oil in the area you fill near the meter often goes bad ... but it was a really thick seal on an indexed bushing of sorts. would have to find the video to remember what it is called.

If I am going to go through the trouble of draining fuel off, loosing prime, removing the pump housing, etc I want to make sure I get everything "done" for the season.

definately change the seals and gasket as a set. cuase while its apart its easy. and todays fuel attacks the old seals as it doesnt have the sulphur which did keep em supple to a certain degree.

As t--88 says, if you don't take it apart and fix it you will later wish you had done it. Taking the inj pump off is not a big deal although you may cuss a bit getting it back on with some of the bolts hiding behind the pump. Just make absolutely certain to keep dirt and crap out of the fuel lines and the pump. Clean everything up before removing. Good luck!.