can a p7100 mix fuel and oil internaly?

O

oil_burner

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The last couple times I've checked my oil, theres been some some yellowish foam almost, all over my dipstick and its also all over the front diff under the blowby tube. It seems to me it has to be fuel mixing with oil. I'm pretty sure its not my injectors, they have about 5k miles on them and set at 290 bar. All i have is a little blueish haze when its cold out at idle, dosent seem like any raw fuel. Cant be mixing at the factory lp since its gone, running a airdog. The only thing i can think of is its mixing in the ip, but not sure if its even possible as i dont know the internals of the pump that well. Any advice would be great, thanks.
 
its not mixing any oil in coolant and if i just crack the drain plug after sitting for a while no coolant or water comes out first. so i dont think its coolant in the oil. could be wrong though
 
Its coolant in the oil. The yellowish stuff you see is from the water evaporating when the oil gets warm. So I'd say you have a small leak somewhere ie. Headgasket slowly going or a cracked oil cooler.
 
Makes sense, that would also explain why its using a little coolant too. headgasket only has a few thousand miles on it and is oem. Head was surfaced and got o-rings at the same time. Did initial toque and 2 retorques about 500 miles apart. Is it possibly with the orings it just needs torqued again?
 
To answer your question yes a 7100 can leak fuel into the crank case.
 
It mixes inside the pump and returns with the oil into the front cover. Ours was pushing fuel past the o-rings and into the oil
 
Not sure. Ours was fine. Sitting on the line brought the rpms to 5k and it filled the crankcase with fuel. Pump shop said the o rings were bad
 
it leaks past the barrel oring when using a lot of fuel pressure if i was to guess. ive never seen it personally but have heard of it. would explain oil in fuel. also could leak past the plunger if they were in really wore out if i was to guess.
 
When i first put my airdog on it ran about 55psi for a couple weeks untill i turned it down. Its now at 38 idle and drops to 35 at wot. I've herd of guys running 60 plus in 160 pumps, so i dont really consider mine really high fp. weather its fuel or coolant, its not very much, just enough to be noticable. I would think if that oring went it would be literaly dumping fuel in the case like disturbed said.
 
Could be condensation in the crank case, humid climate With colder temps & not getting the engine warmed up good at each start can cause it. You could do the taste test on the yellow foam, if it is sweet it is coolant. have never seen fuel in the oil cause any kind of foam.
 
My 245k mile 160 pump on the Junker Drag Truck doesn't mix fuel and oil, it's seen as high as 115 psi fuel pressure. Although when it's not at the track racing, it's kept to a more reasonable 65 psi.
 
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