thomase

Problems again. My air conditioning compressor has been making several
noises. When the weather is wet it sounds like the motor from one of those
big industrial refrigerators. That noise is the same regardless of whether
the I have the air cond turned on or not. Then at times it makes the noise
of a pepper grinder running at 1000rpm. Still at other times it makes a
light knocking sound which increases if I actually turn the air
conditioning on. Even stranger, my power steering pump also makes some
whistling noise and the alternator also makes a similar noise. What is
going on? Is this one and the same problem or 3 problems? I have checked
the tension on the belts and they are not overtight. Sometimes in the
summer, I can hear the air conditioning belt slipping for a split second
once every minute or so as the compressor engages and disengages while the
air conditioner is on.

thomase

Today I removed all the belts and indeed without any belts the engine is
very quiet. I only run the engine this way for 30seconds though because,
of course, without belts the water pump was also not running. Then I added
the 3 belts back one by one and the noises also returned one by one. Adding
the alternator/water pump belt added a chirping/hissing sound, which seemed
to be coming from the alternator. Adding the air conditioner belt added
that “old refrigerator” and light knocking sound and finally adding the
power steering belt added another chirping sound.?!

Another strange thing is that with the belts off I inspected the rotation
of all the pulleys. There does not seem to be any play in any of the axes
and bearings (air cond pump/alternator/power steering pump and pulleys and
water pump). Also when I rotate the axles by hand the operation seems very
quiet and smooth ???!

The truck has 72K miles.

thomase

Yesterday I bought a “belt quieting” spray and applied it on all the belts,
I was able to spray the power steering and air conditioning belts while the
engine was running but I had to turn the engine off to spray the water
pump/alternator belt. The noises did not go away, although there was a
small (I underscore small) change in the noise pitch. Then when I
restarted the engine a few hours later, the noise(s) were more pronounced
but that could have been a coincidence since just as the noises started
gradually from nothing, I expect them to get worse with time.
So I’m still puzzled. It’s really difficult to determine where the noises
are coming from although it seems that the hissing sound comes from the
direction of the alternator, the chirping sound from the power steering
pump and the knocking sound from the air conditioning compressor, does
this make any sense?

Oh yes, BTW there has been another unrelated noise that I’ve had for a
while now. When I make a close left turn with the steering wheel almost
completely turned and I simultaneously happen to hit a bump, I very
briefly hear this very loud screeching noise which does not sound good at
all. Seems to be coming from the right front wheel. I’ve ignored it and
just stopped taking close left turns if there are bumps, however any
advice on that would be appreciated. I had once taken the truck in at the
dealership and they told me that they lubricated something and the noise
stopped for about 3-4 months but then reappeared.