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oil leak

Discussion in 'T3 & T4 Tech Help Clinic' started by petersbilt, Apr 21, 2022.

  1. petersbilt

    petersbilt New Member

    hi all have a question about some leaking oil , coming from underneath it looks like its dripping off the starter motor securing nut. have rang my mechanic he says maybe the rear main seal has gone meaning the engine has to come out to fix it. has any one had the same problem and is it a big deal to get the motor out , its not leaking a lot of oil where I am topping it up all the time but can it get worse if I leave it thanks regard petersbilt.
  2. Luckyphil

    Luckyphil Well-Known Member

    Find a new mechanic. The gearbox needs to come out not the engine. Good opportunity to check the clutch components while at it.
  3. syncro

    syncro Well-Known Member

    Southern Highlands
    Is it normal to pull the engine or the box? I suppose the coolant would be the problem with dropping the engine. I've never removed an engine or gearbox on a water cooled T3 before. Done plenty of air cooled and it's much easier to take an engine out than a gearbox.
  4. Maccas

    Maccas Well-Known Member

    Gosford, NSW
    Sounds like a guess by the mechanic. You want him to pull the gearbox out on a guess?
    I know it's not easy and you may need to be persistent and in the end be unsuccessful, but first put in some effort to trace the source of the leak.

    Degrease as much as possible of exterior of motor, drivetrain etc components, then inspect regularly, you MAY get lucky and backtrack the oil leak to its source. Leave the checking interval too long, the source becomes harder to find. Good luck. :eek:
  5. Grantus

    Grantus Well-Known Member

    Southern ACT
    As already posted, a full degrease, (the rattle can degreasers from auto shops are very cheap), and pressure wash first, to clean up, and then to establish exactly the source on the externals, as to where the leak is originating. (A leak can track a long way, before it drips.)

    Should then be indicative of the next required step.
    Syncro27 likes this.
  6. Barry

    Barry Well-Known Member

    Abbotsford NSW
    dumb question ………but what oil would be that high?
    grumble likes this.
  7. Wiz

    Wiz Well-Known Member

    Near Ballarat
    Once cleaned up as described above...
    Establish if it's engine or gearbox oil?
    Oil clean or dirty?
    What sort of smell?

    If it does turn out to be rear main seal make sure you check wear on shafts, replace gearbox input seal at same time, and lubricate seal lips.
  8. T1 Terry

    T1 Terry Well-Known Member

    Mannum South Australia
    Maybe you parked it near a bay kombi and it's learnt how to mark its territory :lol:

    T1 Terry
    grumble and Luckyphil like this.
  9. hairyman

    hairyman Active Member

    Sydney, NSW
    As said by everyone else, taking the gearbox out to get to it is much easier than taking the engine out, in a watercooled van. Smell the oil that leaks out. If it smells like moly grease then it is gearbox oil, and if it smells like the dipstick then it's engine oil. I'd reckon it's more likely to be engine oil since that system is pressurised but the gearbox is just sloshing around. Consider getting your clutch replaced and CVs services while you are at to avoid having to do it again for a while.

    what happens (for my experience at least) is that engine oil seeps out of the crankshaft seal behind the flywheel and gets flung by spinning flywheel all over the inside of the flywheel/clutch housing as the engine runs, so it comes out all over the place.
    Wiz and Barry like this.
  10. Syncro27

    Syncro27 Well-Known Member

    Terrigal, NSW Central Coast
    In a water-cooled T3 manual, it definitely easier to remove the gearbox than the donk. Auto has coolant running through it unless it has been upgraded to an oil to air cooler and that creates an issue yet still easier to drop the box.
    grumble and syncro like this.

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