I'm also no expert ... but here's my thinking. Auto engines have an oil pan
located below the block where the engine oil is cooled to some extent
because it's exposed to the air (heat transfer to the air through the pan
that is). Boat engines don't have that luxury, the easiest solution for a
marine engine being to use a water cooled oil cooler ... my I/O for example
has an oil cooler ... I'm guessing most marine engines turbo or not have a
cooler. So I'm saying the cooler is not used so much to accomodate the
turbo.But ... I'm thinking the turbocharger will add further heat to the oil
.... yes ... as far as I know, engine oild is used to lubricate the turbo ...
just ask anyone who's lost a turbo seal to suddenly have all the engine oil
pumped outta the system. If it was me, and I wanted to lose the cooler, I'd
look into say a quality synthetic agreeable with your engine/turbo ... after
all, the purpose is lubrication (but high temperature is not good for that
standard oil).


Pascal Goncalves wrote in message
om...
Whay turbocharged engines have oil coolers?

I have a Volvo Penta 2003T engine in my 1992's 36 ft sailboat; this
a turbocharged version of the 2003 and it have an Oil Cooler
instaled inline, before the fresh Water cooler. The oil cooler is made
of aluminium with the inner tubes of cooper, and because it uses raw
water, is prone to corrosion. A new one, woul cost to me, here in
Brazil, about US$ 1,200.00 wich I think is unaceptable.

This engine is 45 HP, and has a turbocharge (turbine) but the
operating temperature is not so high; the thermostat begins open at
74 °C and is fully open at 87 ºC; the new Volvo Penta 2040 wich is
not turbocharged and has 40 HP, operate at a higher temperature
(82-95°C) but does not have an oil cooler. Both engines uses the same
lub oil (15W40).

The oil cooler, is a very critical piece, since it can cause the
complete desctruction of the engine, in case of the raw water goes to
the engine lub oil. I am tempted to eliminate this oil cooler
bypassing it and not refrigerating the lub oil at all. What would be
the drawback? I use this motor very lightly, at 2,000 rpm, not at
the maximum 3,200 rpm.

Thanks for the help

Pascal Goncalves
Salvador-BA-Brazi