getting fuel in my oil still

[Tremblor]

I posted awhile back about having my oil level increase even though the oil level sensor is leaking very badly. I'll check my oil before i go uptown, then when i checked it when i got back it had climbed a quarter liter. the oil has a green tint to it, but no milky in the oil. it also smells of exhaust or gas... any ideas? my coolant level seems to be fine.

 

[jd4242]

Next oil change change your water also and put a uv dye in the water then check your oil with an uv light.have you done a compression test yet?

 

[JDraper]

Pull the vacuum line off the fuel pressure regulator and check for presence of fuel. If you have fuel in the vacuum line, you have a bad fuel pressure regulator, which will suck fuel into the vacuum system. If not, at least you can rule that out easily.

 

[Tremblor]

I did a compression test and it was 1 - 170 2 - 168 3 - 171 4 - 145 5 -170 6 - 170. i checked that vacuum line from the fuel pressure regulator and there was nothing in it. but some days it wont let any fuel into the oil some days it will?

 

[shaggymane]

You've got an odd problem for sure. I've had mechanical fuel pumps breach the seal between crankcase and fuel pump. That one was also dripping oil out it's vent. I've also had a mechanical pumps spray a fine mist of oil from the pivot pin. wouldn't have thought such was possible had I not seen it. But that's no help here.

It's been a while since i replaced my FPR but I do remember there's an O-ring to seal it where it goes in. I don't recall looking down the that hole. Maybe some one else knows what's down there. I'm wondering if that goes down to the crankcase. Don't know why it would but then don't know why there's an O-ring there either.
Heck, go for it. Pull the FPR out and have a look at the bottom of it.
See where the hole goes.

 

[rhauf]

if you have a bad fuel injector, one which leaks, every time you shut off you're engine, the residual pressure in the fuel rails/lines/regulator etc, will dribble out that leaky injector, into the cylinder, creep past the piston rings and end up in the crank case.

my guess is bad fuel injector. does it ever kick out a little black smoke on startup?

 

[Tremblor]

It never kicks up black smoke when i start it, and all the spark plugs burn flawlessly. If an injector was leaking wouldn't it foul a plug? I also did a fuel pressure test, it was 35 psi on ignition, 38 while running, and held 38-40 for 10 minutes. and didnt go down it went up. If a fuel pressure regulator isnt that expensive i might just replace it and see if that changes anything. If i drive the truck really careful and keep it below 2000 rpms it does not seem to leak fuel into the oil, but that is just a rough test.

 

[rhauf]

The fuel pressure regulator is not the problem. those fuel pressures are fine and there is no way for the regulator to fail causing fuel to get into the oil.

i still think it's an injector leaking after the engine is shut off. dribble, dribble down and gets past the pistons into the crank case.

have you ever had a carb'd car with an electric fuel pump, and forgotten the fuel pump on? the carb will drip now and then and in the morning you'll have extra high oil level (full of fuel) i think the same thing (on a smaller scale) is you're problem.

 

[Opera House]

I would pull the drain plug and fill a tall glass jar. Let it sit for a week. Gravity will sort things out. That should be telling. Can't fix a problem unless you know what it is. Green sure points to coolant. Gas tends to darken oil quickly as it cleans the engine.

 

[Tremblor]

With doing that fuel pressure test and leaving it on for 10 minutes afterwards and the pressure not coming down at all, wouldn't that signify that the injectors are not leaking, and wouldn't the plugs be fouled if fuel were to leak through the cylinder?

 

[Tremblor]

I would pull the drain plug and fill a tall glass jar. Let it sit for a week. Gravity will sort things out. That should be telling. Can't fix a problem unless you know what it is. Green sure points to coolant. Gas tends to darken oil quickly as it cleans the engine.

Funny you say that. I have a container of oil sitting in my garage from my last oil change a week ago, ill go check it. And also, the oil i use is mobil super 1000 5w30, and it looked pretty green when i put it in fresh. And my coolant levels are not low.

 

[rhauf]

With doing that fuel pressure test and leaving it on for 10 minutes afterwards and the pressure not coming down at all, wouldn't that signify that the injectors are not leaking, and wouldn't the plugs be fouled if fuel were to leak through the cylinder?

If it is still presurised 10 minutes later that would indicate that the injectors are fine... hmm...

however, a leaky injector wouldn't cause a fouled plug, if it were only leaking when it was off it'd only run rich for one or two firings, it takes continuous running rich to foul plugs.

 

[Tremblor]

Well, in the beginning of January i am going to install a new fuel pressure regulator, and new upper and lower intake manifold gaskets. the only 2 things it could physically be at this point. i just need to wait for the funds.

 

[Opera House]

I'm not a big fan of just replacing things willy nilly. There is no sign that you need a FPR. Did you check the gas tank venting system? Those little see through gas filters in vacuum lines are a good way to check for fluids that might show up. This isn't magic. There are only so many sources and they leave clues.

You are due for a transmission vacuum modulator leak at this age.

 

[Tremblor]

yea, willy nilly aint a good way to do things. I'll check the fuel tank venting lines. Is it actually possible to seep fuel through the intake manifolds into the oil?