This is my first Volvo, a 91 740 turbo wagon 4 speed
with o/d, 126k miles. I got it only less than 3 weeks ago. There
were a lot of little things not working or not working
right. I’m almost done fixing them. I remember that
the first few days I drove it, I can hear the hissing
or whining of the turbo when I step on the gas pedal
(I assume that's how it should sound like.). Started from
a few days ago, instead of that sound, I hear a light rattling or
clicking clunking sound (not too loud, but it’s there)
whenever I step on the gas and when the turbo gauge
needle just turns past the mid point. The sound feels
more obvious as soon as my foot gets of the pedal and
stops in a second or so. It never does that when the turbo gauge needle is on the left region and can not be reproduced by just reving up
the engine at neutral. What’s wrong? Could it be
something else or I just plainly need a replacement
turbo? Thanks for your help. Erwin