|
I
have a 3.0L, four-cylinder in-line gasoline stern drive and do most of
my own maintenance. Lately I’ve noticed some oil leakage around the
oil pan. What could be causing this?
A.V., via e-mail
Oil
leakage around the oil pan can be caused by several factors.
One is excessive torquing
of the oil pan screws when a new gasket is installed, causing the gasket
to be deformed and squeezed out. While the typical one-piece silicone
rubber gasket includes metal spacers around each of the screws to prevent
this from happening, over-tightening is still possible. You’ll have
to replace the gasket. Refer to your engine manual’s specs on the
correct torque for this application.
Two other possibilities
are a defective gasket and one with insufficient contact or "crush"
in certain areas to make a good seal. This is commonly caused by residue
from an old gasket that was not removed during installation. Yet another
cause could be deformation of the pan’s flange. If this is the case,
you can usually straighten out the flange by tapping it lightly with a
hammer. If not, a new pan will be needed.
Finally, the leak may
be coming not from the pan but from either the front or rear main-bearing
seals. The seals could be worn or defective, or if you’ve had any
work done on the crankshaft, the problem could be mismatched surfaces.
If this is the case, you’ll either need a new crankshaft or have
to have yours machined.
During
a routine maintenance inspection of my cooling system’s freshwater
pump, I found the impeller blades to be pitted. What could have caused
this? T.L., via e-mail
Besides
the obvious culprits–sediment, rust, and similar contaminants causing
abrasion–air in the cooling system can cause a condition known as
coolant foaming that will promote pitting of water pump impellers. The
situation is worse if the air is caused by exhaust gases.
Leaks are the usual
cause, so regular inspection to ensure hose and clamp integrity, proper
seating of all seals, and proper pressure cap and thermostat operation
is important. Flush your system regularly, following the engine manufacturer’s
directions, and always refill with approved coolant. You may also want
to check your engine owner’s manual for recommended coolant additives,
many of which contain defoaming agents.
Next page
> Total Base Number, and more > Page
1, 2
|