Gas in the oil?

[tgreene92]

So i took my new rig for a test drive after finishing everything up, it was running a little funny so i ran some tests and then looked at the oil, what do i see, white on the oil cap. I took a whiff of it and theres definetly gas in there. I was going to rebuild the injectors anyway so i pulled down to them and there definitely clogged, im hoping thats it. Any ideas what it could be? Im considering just replacing the head gaskets and everything up just to be safe. BTW its a 98 xlt 4.0 sohc.

 

[fsumotorhead]

clogged injectors woudn't cause gas in the oil, but stuck open ones may.

I would start by doing a compression test to see if your rings are in good shape.

 

[SkyJumper]

Many things can cause this, some are, from a short driving cycle that doesn't allow the engine to fully warm up, to a faulty fuel pressure regulator, to leaking fuel injector/s, to worn engine parts, like piston rings, valve guides, faulty spark plugs resulting in poor fuel burn ect, ect.

Cylinder ring blow-by is a common occurance, along with bad valve seats.

 

[tgreene92]

Many things can cause this, some are, from a short driving cycle that doesn't allow the engine to fully warm up, to a faulty fuel pressure regulator, to leaking fuel injector/s, to worn engine parts, like piston rings, valve guides, faulty spark plugs resulting in poor fuel burn ect, ect.

Cylinder ring blow-by is a common occurance, along with bad valve seats.

yea i knew it could be all those, actually read that exact quote somewhere else, still have to check the pressure regulator. the engine was run enough that sitting wouldnt cause the issue. piston rings are assumed to be good since neither the engine or exhaust are smoking. EGR passed its test, 02 sensors are good. clogged injectors wont directly cause gas in the oil, but when they get clogged the o rings and caps can break which would then cause a leak. 2 injectors have busted o rings and the 2 others are clogged pretty good which leads me to believe that the clogs are what busted the orings.Im going to rebuild the injectors, clean out the upper and lower intake, reassemble then run a compression test. I ran one a few months ago when i got the rig and everything checked out. Any other ideas what it could be? Im also going to replace the spark plugs and wires, as i might not be getting enough fuel burn either.

 

[ctiggs88]

ya if its not running very well id say you have poor spark which isnt burning fuel correctly and transfering it into the oil or a bad injector. is the check engine light on at all? it would be helpful if you could narrow it down to 1 cylinder. ive ran into this problem with a few vehicles at the shop in which they wont really smoke no matter what becuase of 4+ cats doing there job a little to well lol if you have a dead misfire id say go 1 by 1 and pull off each plug wire 1 cyl at a time until you pull off one that doesnt cause the engine to run differently. that way you can start by just putting 1 spark plug in the cylinder with a misfire to see if it fixes your problem and u dont waste your money on tune-up parts just in case it doesnt fix it. just my 2 cents! good luck man!

 

[ctiggs88]

thats saying your injector replacement doesnt work...from what it sounds like you need those anyway!

 

[Pontisteve]

Are you sure it's gas in the oil? Gasoline is a solvent, and generally is invisible in the oil. It just thins it, and makes it stink like gas. The concern with this issue (besides the cause) is that you could cause crank bearing failures due to hot spots and lack of lubrication.

White foamy looking stuff on the oil cap is usually a sign of water in the oil. Plenty of it, usually on the dipstick as well, is a sure indicator of a blown head gasket, cracked block, cracked head, and possibly a blown intake gasket. Anything that leaks water into nearby oil passages. Most often, this is a blown head gasket.

Head gaskets can blow in different ways. Compression from cylinder to cylinder, or cylinder to outside. Water into oil and vice versa. Or compression into water. A compression or leakdown test would find if compression is leaking, but not necessarily if water is leaking into the oil. For that, you would have to pressure test the cooling sytem.

It's also entirely possible, if only a very small amount of water is present in the oil, that its just condensation. I see that in race motors every so often when we pull the valve covers. Surprising amount of white oil, sparcely spread.

An unexplained loss of water over time would be an indicator of a head gasket also.

If it's an EFI engine with an electric fuel pump, then there's only one way that fuel can get into the engine. And that's due to leaky injectors. If one sticks open, it can drip (engine off) or continually spray (engine on) into the combustion chamber. There, it will end up washing oil off the rings and cylinder walls, contributing to premature cylinder wear if not fixed. After rinsing past the rings, it ends up in the oil pan and mixes/dilutes the oil.

Injector O-rings generally only seal the injector to the fuel rail or the intake manifold. O-rings should not cause any flow issues. If O-rings are bad, the injector leaks externally.

To a much lesser degree, a weak ignition (bad plugs, wires, possibly coil) could cause a misfire, and enough misfires will leave unburned fuel in the combustion chamber. Left misfiring, fuel could wash the bores and end up in the oil. But the motor would run like crap, and you would know it.

 

[tgreene92]

Are you sure it's gas in the oil? Gasoline is a solvent, and generally is invisible in the oil. It just thins it, and makes it stink like gas. The concern with this issue (besides the cause) is that you could cause crank bearing failures due to hot spots and lack of lubrication.

White foamy looking stuff on the oil cap is usually a sign of water in the oil. Plenty of it, usually on the dipstick as well, is a sure indicator of a blown head gasket, cracked block, cracked head, and possibly a blown intake gasket. Anything that leaks water into nearby oil passages. Most often, this is a blown head gasket.

Head gaskets can blow in different ways. Compression from cylinder to cylinder, or cylinder to outside. Water into oil and vice versa. Or compression into water. A compression or leakdown test would find if compression is leaking, but not necessarily if water is leaking into the oil. For that, you would have to pressure test the cooling sytem.

It's also entirely possible, if only a very small amount of water is present in the oil, that its just condensation. I see that in race motors every so often when we pull the valve covers. Surprising amount of white oil, sparcely spread.

An unexplained loss of water over time would be an indicator of a head gasket also.

If it's an EFI engine with an electric fuel pump, then there's only one way that fuel can get into the engine. And that's due to leaky injectors. If one sticks open, it can drip (engine off) or continually spray (engine on) into the combustion chamber. There, it will end up washing oil off the rings and cylinder walls, contributing to premature cylinder wear if not fixed. After rinsing past the rings, it ends up in the oil pan and mixes/dilutes the oil.

Injector O-rings generally only seal the injector to the fuel rail or the intake manifold. O-rings should not cause any flow issues. If O-rings are bad, the injector leaks externally.

To a much lesser degree, a weak ignition (bad plugs, wires, possibly coil) could cause a misfire, and enough misfires will leave unburned fuel in the combustion chamber. Left misfiring, fuel could wash the bores and end up in the oil. But the motor would run like crap, and you would know it.

Ok this might be a long post, yes im sure its gas in the oil you could clearly smell it on both the dipstick and oil cap, and when i drained the oil it also smelled of gas as well as had an odd tint to it. the little bit of white foam im sure is just from moisture in the gas it really wasnt much at all, ive seen blown head gaskets and what the white foam will look like with that, and that is much much worse than what mine looked like. i also pulled the valve covers yesterday and they were spotless. Yes the injectors were defintely leaking externally because there were puddles of gas all around them, i pulled the injectors apart yesterday and the filters and hats were also in bad shape so i have no doubt they were leaking internally. I defintely also have a weak ignition. the plug wires were newer but the plugs definetely have not been changed in a long time. I think this is just a mix of leaking injectors and and weak spark, theres no other symptoms of more serious problems.

 

[Pontisteve]

Just a reminder, but these motors are under about 40 psi of fuel presure. Any leak at an o-ring could be a very serious fire hazard. Nobody wants fuel squirting on exhaust at 40 psi!

Any gas in the oil must have come from an internal injector leak, or sticking injector. As easy as they are to come by, I would just get some different injectors. But be sure to use stock Ford injectors. If it has the orangish-yellow top 19# injectors, those can be found used very easily, as many Mustang V8s had that injector, and those guys constantly upgrade. Not sure what comes in a 6 cylinder explorer though.

Another route is guys like WitchHunter can clean and flow test your injector, as well as replace the o-rings and injector buckets. But price-wise you can spend nearly as much as just getting new or even used injectors, and new o-rings.

 

[tgreene92]

Just a reminder, but these motors are under about 40 psi of fuel presure. Any leak at an o-ring could be a very serious fire hazard. Nobody wants fuel squirting on exhaust at 40 psi!

Any gas in the oil must have come from an internal injector leak, or sticking injector. As easy as they are to come by, I would just get some different injectors. But be sure to use stock Ford injectors. If it has the orangish-yellow top 19# injectors, those can be found used very easily, as many Mustang V8s had that injector, and those guys constantly upgrade. Not sure what comes in a 6 cylinder explorer though.

Another route is guys like WitchHunter can clean and flow test your injector, as well as replace the o-rings and injector buckets. But price-wise you can spend nearly as much as just getting new or even used injectors, and new o-rings.

yea fortunately i realized the problem before any serious damage was done or something caught on fire, i think theres no sense in buying new injectors or finding other ones, i can rebuild them the same as witchhunter or anyone else would and i have a buddy that said he could test em for me even tho im sure there fine because the truck had no misfires or sign that an injector wasnt working at all.