I'm at a loss. Has any one developed a whistle noise that comes in at about 60mph and is effected(reduced increased) by throttle. Seems to take a few moments to develop but does appear at a sustained 60Mph. Seems to come from dash/front area. Not a wind leak/noise. Very annoying. Any help appreciated on this one. Cat? Vacuum?

Thanks ahead of time,
Randy
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84- 240 dl non turbo

Air leak between the rubber seal that joins the heater/blower/AC unit with the cowl vents on the firewall.
Air hits the bad seal and sounds like the old trick of blowing between two blades of grass.

I STILL have that problem.

Duct tape over the cowl vents to stop air coming in stops the squealing, but also prevents use of fresh air intake.

I have had my entire dash apart to change the blower motor and other things but could not get at this seal without venting the AC freon and removing the AC coil core behind the blower. !!!!!
One of the few design flaws on the 240.

Bert

91 245

Bert, I know 'xactly what you mean...had to pull the box to change a heater core on this 91. Got away with the A/C intact by loosening or removing every relevant clamp under the hood on these 91-up hard-plumbed ACs. Had to take apart the cruise servo, and the left side air plenum, to clear it with the box. I think I was lucky; you're not supposed to do it this way.