On Thu, Dec 02, 2010 at 09:35:47PM -0600, Kaleo wrote:
> Hello fellow liveaboards,
Hi, Matt! I was following you folks on Twitter a while back, and found
it rather amusing to see you pop up here on the list. Welcome!
> This evening the bilge pump seemed to be running more than usual which
> led me to discover that one of the thumb screws on the speed seal for
> the raw water impeller was loose. I tightened it and while back behind
> the engine decided to check the oil, upon pulling the dipstick water
> came gushing out, under pressure and continued to do so for quite some
> time. It cycled the bilge pump about 4 times.
Wow. Even given a really small bilge and a pump that dewaters it down to
almost nothing, that sounds like a *lot* of water. How much water would
you say came out, roughly? Some number of gallons? Also, just to confirm
- the motor _wasn't_ running when this was happening, right?
> While it was coming out
> I popped the radiator cap to check fresh water coolant level. It was
> fine and it did not seem to be draining.
There's no oil in it, correct?
> I tasted the water and it seemed quite salty but I can't imagine that
> salt water got into the crankcase.
I gather you're cruising in fresh water, then?
> Obviously, cooling water is getting in somewhere. Any thoughts on
> where to start trouble shooting?
Depends on your engine configuration, but the most likely place for a
raw water to oil connection would be your water pump - i.e., in certain
(poorly designed) pumps, a rear seal failure would allow the water to be
pumped into your oil system. There are other possibilities, but most of
them involve water from your cooling system. Actually, if you have a
heat exchanger and the oil line in it develops a hole, then
theoretically, water _could_ get forced into the system. If that's the
case, don't buy a new exchanger (they're very expensive); getting one
repaired is fairly cheap by comparison.
Last option in that regard: if you have an essentially flat (no water
trap) exhaust line, and you get water into it - e.g., stern seas while
you're sailing with the engine off - then the water could flood up into
your exhaust manifold, at which point things get rather sticky. The
right answer there - after flushing the engine as below - is to redesign
and rebuild that exhaust system.
Something I find very confusing in your description is, why would the
water *keep* spouting as you described? I can certainly picture a short
spurt, but... the only explanation I can come up with is 1) a completely
gone rear seal - i.e., free communication between your oil and water
systems - and 2) a water reservoir, such as a waterpot in your exhaust
line that's significantly higher than your oil sump.
Hopefully, you carry a spare water pump aboard Kaleo (if you don't, you
should - along with perhaps a spare alternator and a spare starter,
something I consider a part of even a minimal cruiser kit).
If I was in your situation, I'd pop off the water pump and take a good
look at it. Assuming that it was indeed at fault, I'd replace it. Then,
I'd drain all the oil, fill the crankcase with diesel (right up to the
'full' mark and even a little above), and slowly turn the engine over a
couple of dozen times while keeping the kill switch down (you don't
really want it to start at this point.) Drain the diesel, refill with
oil up to the right level, and crank it up. After a minute of two, stop
and check the oil - i.e., make sure your diagnosis was correct, and
water is not still coming in. Watch it carefully over the next few hours
of running time, too; if there's some deeper cause that created the seal
failure in the first place, the problem will come back (yes, I'm a
suspicious untrusting engineer type. Anybody got problems wid dat? :)
I'd also check it pretty promptly after the next incident where you get
stern seas.
> Now I'm at anchor and unsure what to do next. Do I dare drain the oil,
> change it and try to motor into the nearest port (about 10 miles)? Or
> call the tow boat?
Based on what I can figure out, I'd say that you're most likely OK to
run once you've flushed the system; it doesn't sound like a cracked
block or blown head gasket (that would result in your cooling system
fluid mixing with the oil.) If it's the result of a badly-designed
exhaust system, then don't move on a day when you're going to have stern
seas - at least not without the engine running. If it proves to be the
pump, then you're good all around: replace it, flush well, and keep on
cruising.
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