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Gas in the oil


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I bought this Comanche maybe 2 years ago and have yet to have the time to fix this all up. This has been a farm truck its entire life so it has not been taken care of. It is 1987 with the 4cyl in it. The rockers have maybe 1/2 inch of carbon build up on them is that gives you any indication to the care this vehicle had. It also has 65k miles on it so its not much. I have a tick in the rear cylinder and low oil pressure when the engine is warm. The bad part is that there is gas in the oil. Not just a smell but you can see it rising on the dipstick just after a 10 minute ride. I have checked compression and they are all the same except the rear cylinder which has maybe 15 more pounds of compression. I have also did a leak down test and that turned out without any problems. The exhaust manifold is cracked and will be replaced and the engine will be flushed but I have to get the gas problem fixed before anything else. Spark plugs are burning like they should be so I am stumped as to where the gas is coming from since I have good compression.

 

Any help would be appreciated.

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The injector may be gummed up and not closing when "off." The fuel system is under pressure. When you shut off the engine, the pressure may be forcing raw gas into the intake manifold. On a later 2.5L with MPFI this gas would drip directly into the cylinders, but with yours it may be getting sucked in during those few revolutions afte you shut off the ignition while the engine is shutting down.

 

You're sure it's gasoline and not coolant?

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Thanks Eagle. I am sure is is not coolant. I verified it with UV dye. I thought the injector may be leaking when turned off so I checked it and there is no leakage when turned off either. Now I do not remember if this is normal or not but I do have a slight amount of gas coming from the top of the injector like a bad o ring. Not a lot but just a small bit. The throttle bore was clean by the butterfly but up top it is dirty. That may be a sign of the fuel at the top of the injector also. It has me puzzled to no end.

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Do I have everybody stumped like I am?

 

My theory is that since the manifold is leaking the O2 will see a lean condition and try to richen it up, makes sense. But how is the gas getting in the oil since I have great compression and no leak on the tester?

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