8YL67821 Changed filters last set to note oil contamination in fuel. Had been using around a gallon or so in 200hours. Previously put it to wear. Seemingly apparent that it is actually going into the fuel. Changed all injectors for reman units from cat. No change. Have a fuel transfer pump to replace tomorrow. What else would cause this if it's not the transfer pump?
Aside from a cracked passageway in the head the only other thing I could suggest is the lift pump on the back of the HPOP. But I would think if that were a problem, you'd have a hard time maintaining ICP. Maybe Nige has come across this before.
I vaguely remember something about the pressed-in injector sleeves in the head. Can't for the life of me remember what it was though. Go with the obvious things as a starting point I'd say.
Thanks Nige Question tho, injector sleeves have coolant the other side. I've seen them fail and put coolant in the fuel. Coolant in the water separator was the tell tale. That's the only reason I've not looked down that route Unless I'm mistaken... Happens!
If I'm right in my thinking, high pressure oil is at the top of the injectors, fuel rail beneath them and coolant at the base.
Yessir
Seems the issues I've ran into with fuel oil mixing after cause was corrected it took longer than thought for oil or fuel to return to normal. I had 3306 with alot of fuel in oil dilution. ( Transfer pump was bad) it took 3 oil changes before oil looked normal. And black fuel can also take awhile to return to normal. I know your very experienced just a thought. In a hurry ended up new injectors and resealing unit pumps on that 3306 just because oil seemed diluted after issue was fixed.
Well, just changed the transfer pump. Guess we'll see... Not so much concerned with the oil in the fuel as much as oil usage Could suck the fuel out of my tanks but seems wasteful.
Typically oil in fuel is from a damaged injector oring.
OP stated that injectors had been changed. I can't imagine that the o-rings weren't changed as well, actually Cat Reman injectors (If that's what was used) come with new o-rings already installed. Thinking out loud how long is it going to take for the oil contamination to go away from the fuel tank even after the source of the oil entry into the fuel system has been located and fixed..?
He's looking closely at oil loss over time. 1 gallon at 200 hours. Don't think that's a bad number if she's an old girl running at 50% or greater load. I'm curious what it's powering.
Service truck by the sounds of it. This one..? HeavyEquipmentForums
Nige You are correct. That is the old girl. When I did the injectors, the tanks were close to empty. Filled both with clean fuel. Not sure how long it will take to work it's way out of the system. Deviating from the original question then regarding oil usage... 33k lbs running weight Fairly severe environment (up and down mountains) Compression brake High hour motor good service history and runs well What would the expected oil usage be?
Pits in the bore where the orings lie will allow leakage of HPO to fuel gally.
Done about 170 hours since changing out the injectors and transfer pump. Not used a drop of oil and fuel seems to be significantly cleaner. Not sure which part was failed but at least my problem is fixed.
Well as you stated in your OP that you had changed the injectors with no visible difference in the colour of the fuel, my money's on the transfer pump.
On face value I'd agree. Only questionable point would be time period for fuel to clean through from the tank. Also, in my experience the transfer pump typically fails in the opposite direction, diluting the oil with fuel. Either way. I'm happy!