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ZZR250 Coolant in oil

Discussion in 'Technical and Troubleshooting Torque' started by lotec, Mar 21, 2011.

  1. Hi Guys,

    Thought i'd ask your opinions on what the issue might be. A while a go, i noticed that the oil had turned a milky brown. There was no overheating issues, and she didn't blow any smoke. So i parked her up for a few months, then finally got around to changing the head gasket on Saturday. There old gasket didn't look too bad, there didn't appear to be any visable cracks in the head, and a quick run over with a steel ruler didn't pick up any obvious warping on the head.

    So I bolted her back together with the new gasket, and it appeared to have fixed the problem. After taking her for a 5min ride, I get back and have a look, and now the oil is a very milky white. I've had it suggested that it may be the water pump seal that's leaking? Or possibly a hairline crack in the head?

    Any thoughts guys?

    Thanks :)
  2. Try the water pump seal, if it fixes it, you dont have to buy another head/engine(cost)
  3. Nod to me next time and I won't pour water in your oil.

    Beat you to it boy.racer:angel:
  4. Try the water pump seals. Get a pressure tester on it. If the cooling system won't hold pressure ... and if you can strip a head off and rebuild it, you know that.

    Good luck.
  5. I stripped down the water pump last night and she's all good (actually, she's in great nick - i'd say it's been replaced by the previous owner). But when i had to drain the oil to get the water pump out, i noticed that it was actually *OK*. Yet the window glass was still milky white, and the oil cap has a bubbly ring of white around it. Is it possible that these are just left over's and that the problem is fixed?

    I put more oil in it, took it for a ride, and drained it again, and it was the same (clean oil, but still milky glass window & oil cap).

    Any thoughts?
  6. You may have left over water or you may be getting condensate in the sump. Take it for a decent ride and get it nice and hot. This should drive out any residual water.

    Take a dip stick and check it regularly.
  7. It looks like the white residue is just leftovers from last time.. Especially if you didnt clean it off.
  8. I'm with ibast. Thrash the hell out of it until you can see the waves of heat coming off the engine, then thrash it a bit more.

    That should boil off any residual moisture.
  9. Don't thrash it. Dump the oil and filter now. Then fill with a cheapo oil and new filter, run for 500kms, then refill with a good oil and another filter.Motorcycle crankcase ventilation systems are very poor, not a positive system as we see on auto engines, you can't rely on the system to actively scavenge what will be a lot of moisture.
    Coolant RUINS bearing material really, really quickly and can also do bad things to some plated surfaces (like Nikasil). Just get that coolant out by flushing it out.
    Even if coolant was pure water, I woudl still state the above.