Can't find high pressure oil leak any suggestions.

FordFanaticTony · May 4, 2016

Hey fellas 15 year Ford diesel tech here and i am stuck. Same crank no start when hot concern. I finished up head gaskets and coolers om truck a month ago. Truck came in towed in. Revved up til hot and ICP reaches about 340 psi. Standpipes, Stc, and IPR has been done before. Did the oil rail nipple cup seals and right side injector seals and so far all good. Still no start. Put about 120 shop air in and i hear it on the passenger side somewhere. Question is has anyone seen the oil rails themselves leak? Maybe crack or porous? This right side oil rail has a porous look to it especially around the area that i suspect the leak. Well let me know fellas if you have any suggestions or if you seen a bad casting on a oil rail. Truck is a 2006 F-550

ktmlew · May 4, 2016

Hook up nitrogen tank. Get some flow!

Bruce Amacker · May 6, 2016

Injector spools worn and leaking?

May 8, 2016

I never tried this, but how about adding some oil dye into the rail then pressure checking. Should pinpoint the leak...

forddieseldoctor · May 9, 2016

Don't forget about the oil rail block off toolsthat allow you to test the oil rails and injectors on each bank seperatly. I just finished a high pressure oil leak on a late 04 that sounded like it was coming from the #7 injector area that ended up being a failed o-ring under the hpop cover.

It started off with an air leak through the #1 injector.

RyanG · May 9, 2016

fuel in the oil? Had a post about it a few months back, drove me nuts.

jimmy57 · May 10, 2016

Fuel in oil (with no obvious diesel smell these days) will kick your butt as will the spool valve issue. I don't know that spool valves cause this without the injectors having had the spool valves polished to address stiction.

Brad Clayton · May 10, 2016

My general rule of thumb on injectors causing a no start is extremely high IPR duty cycle at idle.

FordFanaticTony · May 10, 2016

Thanks for all the tips guys finally found the culprit. It was the right hand side oil rail in the end. I had installed all ned injector top orings and replaced the nipple cups and nipple cups oring and i could still hear a lil bit of a leak only when hot. That was a challenging one. Thanks for all the advise here.