Hey, hoping you can help diagnose a problem we are having with our 1990 240 dl 5 speed wagon. The car has nearly 250000 miles on it, but seeing as we recently bought it used we don't have any of the service history. It has recently begun to make a strange noise as we drive it. It could be described as a howl, or near siren noise. The pitch does change as speed varies, but just slightly. Letting in or out the clutch, braking, turning, or accelerating seem to have no effect on the noise. It usually only lasts from 1-10 minutes, and sometimes won't make any noise at all. We have trouble recognizing where the noise comes from, most recently we decided it was probably from the front, middle of the car. The car displays no other symptoms, and has passed inspection since the noise started. I am lead to believe that our center support bearing has gone bad, my dad is confident that it is an oil level problem in the transmission. Any thoughts? Thanks
-Mike

I'm suspicious of a small vacuum leak, almost speed independent-if not present at idle, but from just off idle and beyond, partic under load, then it's a vacuum leak Has the car evidence of an impact front left? . Could be airleak in fuel vapour cannister in front of that wheel. That was where mine was. Test cannister & plumbing for leaks. Also, there are vacuum operated air controls in the dash-a ruptured one would cause such sounds-disconnect the vacuum feed to the firewall and block it to isolate them out-if that cures it-look in dash for this problem. ) check ALL vacuum hoses for hardness and cracks. They should be a supple fit without leaks. BTW-get under and look-Are there any oil leaks, have you checked the oil level in the gearbox? get under and make sure that your clutch release lever is pulling back fully (some models ommitted the return spring!!!), and NOT holding the bearing in contact with the clutch spring fingers. If so, it will be worn out. Motor speed should affect such. report pls