1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Fuel in Oil

Discussion in '1st Gen. Tacomas (1995-2004)' started by AtomicAutomotive, Nov 1, 2024.

  1. Nov 1, 2024 at 8:53 PM
    #1
    AtomicAutomotive

    AtomicAutomotive [OP] Member

    Joined:
    Jun 21, 2022
    Member:
    #399859
    Messages:
    8
    Gender:
    Male
    Vehicle:
    96 Tacoma 2.7L 4x4
    96 4wd 2.7l tacoma

    Bought it 4 years ago with a blown head gasket and a cracked exhaust. Drove it in such condition until it didn't start this morning. Spent a few hours tearing it down to the crank case from the top side. Cylinder 3 is the problem cylinder...was leaking water to the outside yesterday, and the engine lost all compression today instead of just having weak compression.

    Figure while I'm replacing the head gasket and exhaust manifold, I'd look into the cause of fuel getting into the oil at a pretty abnormal rate. In 20 years of wrenching I've only ever dealt with excess fuel in the oil on diesels. Not sure what to look at on a gas engine. Common sense tells me to clean and test the injectors for proper open/close; is there anything else specific to this engine, or gas engines in general, I should prioritize to check for the cause?

    regarding the rings, willing to open up the crank case and remove the pistons if absolutely needed, but wondering if pouring some low viscosity oil on top and taking precision (accurate to 1/10000th in) depth measurements an hour apart would be sufficient?
     
    cruiserguy likes this.
  2. Nov 1, 2024 at 9:31 PM
    #2
    TnShooter

    TnShooter The TacomaWorld Stray

    Joined:
    Sep 2, 2010
    Member:
    #42625
    Messages:
    21,393
    Gender:
    Male
    First Name:
    Deogee
    Vehicle:
    07' TRD Off-Road, Auto
    STOCK
    I'd suspect a leaking injector.
    I guess a no spark situation could cause the fuel issue too.
    But I'd think you know if you were running on 3 cylinder.
    As for rings, I'd do a compression test on cylinders 1, 2, and 4.
    That should give you a general idea of the rings.
     
  3. Nov 2, 2024 at 12:11 AM
    #3
    AtomicAutomotive

    AtomicAutomotive [OP] Member

    Joined:
    Jun 21, 2022
    Member:
    #399859
    Messages:
    8
    Gender:
    Male
    Vehicle:
    96 Tacoma 2.7L 4x4
    I went into the teardown a little zealously having seen the water leaking from between the jead and block yesterday so I've already got the engine torn down to the block. After I get the head back on I'll do a leakdown test before complete reassembly since the valves are still fully seated. Definitely going to clean and test the injectors, though, and replacing all the plugs. Cylinder 3's plug is going to need a helicoil...the old plug was definitely crossthreaded into the head and looked to be burned away. I'm thinking at some point before I came to owning it, plugs were changed, it got cross threaded, and when they were next due only the other 3 were changed and cylinder 3 went dead, leading to a chain of failures to follow.

    But yes, the engine has been running on just 3 cylinders the last 4 years...probably much longer.
     
  4. Nov 2, 2024 at 3:04 PM
    #4
    ControlCar

    ControlCar My Moto: Help & Learn…period.

    Joined:
    Jul 22, 2023
    Member:
    #429578
    Messages:
    3,617
    Gender:
    Male
    First Name:
    Steven
    Sugar Land TX
    Vehicle:
    1996 Taco 2.4L 2wd Automatic
    Clock Volt meter/LSPV Delete/Hyundai 16’s/FP gauge/after 9months of wrenching ZERO oil leaks
    Tn is right on point

    the only way fuel can mix with oil
    (aside from an idiot owner pouring gasoline into oil fill)
    Is in combustion chamber
    Worn rings and/or failed injector(s)

    as you confirmed, #3 is an issue
    Most likely combo of both
     
  5. Nov 2, 2024 at 3:07 PM
    #5
    TnShooter

    TnShooter The TacomaWorld Stray

    Joined:
    Sep 2, 2010
    Member:
    #42625
    Messages:
    21,393
    Gender:
    Male
    First Name:
    Deogee
    Vehicle:
    07' TRD Off-Road, Auto
    STOCK
    If you drove with #3 being dead, you might have washed out the cylinder with the fuel.
    Fuel is not a good lubricant, it won't protect the rings and bore like oil.
    See if you can tell a difference in the cylinder bore color and "texture" compared to the other cylinders.
    If it's washed out, you need to hone it at a minimum. You need crosshatch to retain oil.
     
    ControlCar likes this.
  6. Nov 2, 2024 at 4:04 PM
    #6
    AtomicAutomotive

    AtomicAutomotive [OP] Member

    Joined:
    Jun 21, 2022
    Member:
    #399859
    Messages:
    8
    Gender:
    Male
    Vehicle:
    96 Tacoma 2.7L 4x4
    Thank you for that tip. I'm picking up parts in the morning, so I'll check the surface before heading to get them in case I need new rings and/or sleeve for #3.
     
    TnShooter[QUOTED] likes this.
  7. Nov 3, 2024 at 11:38 AM
    #7
    Red_03Taco

    Red_03Taco Well-Known Member

    Joined:
    Nov 2, 2021
    Member:
    #381170
    Messages:
    1,814
    Gender:
    Male
    First Name:
    Jerad
    Vehicle:
    2003 Tacoma Xtra Cab 4WD
    Quite impressive that the motor ran on 3 cylinders for 4 years
     
    ControlCar likes this.

Products Discussed in

To Top