I thought I had the belts tight enough; as this was my first theory for the
source of the noise. Last night I took apart the raw water pump and removed
the impeller (wow that was easy). It did not have any worn flat spots,
however, there were a couple of large chunks mssing from a couple of the
impeller blades. Also the rubber impeller was dry and relatively hard. I
have a volvo shop manual and it says that the impeller should be lightly
lubricated with grease. There was definitely no lubrication left on this 4
year old impeller. I will replace, adjust belt to proper tension, and see
what happens. I am thinking that this was likely the source of my noise.
--
John A

"Rod McInnis" wrote in message
...

"John A" wrote in message
...
I have a 1999 3.0L volvo engine that has developed a loud screeching
sound
that lasts for 2 - 5 seconds after starting. Originally I thought it was
a
belt, but the belts all look fine.

Does "looking fine" include being tight? This is a typical symtom of a
belt that is not tight enough. When the engine starts, and the belt is
cold,
the poor belt friction has a tough time getting one of the pulleys to
start
turning. After the belt slips for a few seconds the friction heats the
belt
up and its grip improves. Once the pulley starts to turn it is far easier
to keep it turning so it doesn't slip any more.

When I take off the belts and turn
these pullies, they all turn freely except for the water pump (volvo has
a
belt driven water pump on the engine, not in the outdrive, that pulls
the
water in). I can turn this pully but it is very hard to turn. Should
this
be
hard to turn by hand?

If this is the circulating pump (like a car would have) then it should
turn freely.

If this is the raw water pump, which contains the rubber impeller, then
it
would have a significant amount of resistance to turn, especially when it
is
"dry". This is why you can't run the engine on the trailer without
providing water to the inlet, as this friction will quickly cause the
impeller to heat up and self destruct.



I am now suspecting that this may be the root of my
screeching sound. Maybe a new impeller and/or bearings are in order?

First, make sure all the belts are tight.

Second, change the impeller. If you haven't changed it in the last couple
of years then it needs to be replace anyway.

If that doesn't fix the problem, then try to eliminate which device is or
isn't causing the problem. If you have more than one belt, try removing
one
and start the engine (just briefly). If it still squealed, you can rule
out
anything driven by just that one belt. If the squeal stopped, then either
that belt was too loose or something it is driving is too tight.

Rod