240 smoke under hood - not oil leak

My 1985 240 has high miles, so maybe this is a belt problem, but I don't
know. Smoke comes from where the crank shaft (I don't even know if I'm
using the right terminology here) goes forward to meet the belts - toward
the front center under the hood. It's most noticeable when first running
after car has been sitting for a while.

Belts look okay to me, but I really don't have a clue. There's no
screaching sound, but I do hear a fluttering sound which is also
noticeable when first starting up, then goes away. Both symptoms seem to
have started around the same time. Wonder if these are related.

Any ideas, anyone? Thanks so much for imput.

 

The crankshaft damper pulley is defective. The outer sheave set is a
press fit over a rubber sleev to the hub. When they get older the rubber
shrinks and the sheaves spin reluctantly over the rubber causing smoke.
Once the rubber heats up the whole mess sticks together for a while and
then repeats the process over again each time the car sits long enough
for the parts to cool. Eventually the sheave section will just fall off
and all the lights on the dash will come on. You will lose operation of
the water pump, alternator, power steering and air conditioning if
equipped. Usually the pulley just falls off toward the motor as the car
is moving, however if it falls off during braking it can damage the
radiator. I'd get it fixed fairly soon.

Bob



-- The goal when driving is to miss the maximum number of objects.

 

It happened to our 765T when my wife was tooling around town. Imagine her
surprise to see a big chunk of her car rolling into the ditch behind her
after the lights came on and the steering got heavy!

Mike

 

Thanks very much to the two good people who replied. I just looked under my
hood again this morning, and I see that coolant is collecting (in a little
pool) on top of the case, just behind the fan and below the housing for
what I assume is a concealed belt. (Is that the timing belt? Again, I
really don't know a thing about car parts.)

So, it's just coolant that blows off the first few minutes of operation. I
wonder where the leak source is. I don't think it's a hose. All the hoses
to and from the reservoir and radiator are below the coolant "pool." Can I
assume the metal engine case above the spot is leaking around some seal of
another?? Does this make sense? The car has 260K miles, so nothing would
surprise me at this age. If so, can I assume this would be a very
expensive repair, as everything must be taken apart.

Thanks again, Volvo people.

 

Water pump is probably shot. But have the other issue checked out as
well since it has the potential to be dangerous.

 

Aha. The water pump is housed in the same compartment as the timing belt,
right? If so, that's just above where the coolant is collecting, I think.
Assuming the water pump needs to be replaced, I'm wondering about the
labor and parts costs. Does the timing belt need to be removed, or is this
a quick and inexpensive procedure (assuming an experienced Volvo mechanic
performs the work)?

 

Since the timing belt should be replaced every 50,000 miles or so, you
might as well have it all done at once. The water pump can be replaced
without removing the timing belt, but not vice versa. This is pretty
standard stuff, any competent mechanic can do it. But the water pump
won't be the cause of the smoke that is being seen.

 

think a jammed or binding bearing on one of the pulleys or the main
crankshaft pulley might have lost its rubber damper allowing the pulley to
move in and out on the crank shaft .