Nasty noise from 1990 740T Interior Fan (Heater)

There is this whining noise coming from the interior heater fan, when I turn
on the heater. Its on the passenger side and it sounds like a cat being
killed slowly. I think I'm gonna have to get behind the glove compartment
box and take a closer look.

Any tips as to what this might be or how to handle it?

Thanks.

Matt

 

If it's the same as the '87, it's the same fan motor as a Chevy Celebrity
uses, I think they may have updated the heater box design by that year
though in which case I don't really know. In the older cars you get to the
fan from underneath the dash, it's covered by the same cover to the right of
the passenger's feet as the ECU is behind.

 

I just had to replace mine. It is located to the right of your passengers feet.
You can locate it by sound pretty easily. On my car I had to loosen the plastic
piece on the floor in the doorway which enabled me to remove the plastic kick
panel. Remove the computer brain leaving it plugged in and tuck it out of the
way and remove the housing so you can get your hands in easily. I had to pull
the carpet and padding way back out of the way and found it much easier than
leaving things in place. When I was doing my fan replacement I saw online where
someone mentioned the new fans do not always have the drain holes. Sure enough
the old fan had the holes and not the new so I added them to match the old fan.
Just be careful to put the fan in straight and that it is not bound up when you
tighten the fasteners. I would recommend turning the fan on and making sure it
sounds right before you button everything back up. It did not take too long if
you discount the breaks I had to take to get feeling back in my hands from
trying to fit them in before I removed the bracket and carpet.
Good luck.
Chris V

 

Thanks Chris,

That was helpful. Where did you get the replacement and what does it cost
and what is it called exactly?

Thanks again,

Matt

 

BTW,

Can't I just WD40 the motor?

 

WD40 is not a long term lubricant. If you could get a drop of oil on
the bearings, that may help, or it may only extend the life of the motor
a couple of days. However, it's hard to get that drop of oil where it
will do any good, especially on the fan end. To much oil will foul the
brushes.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Also the motor is pretty cheap, I got mine for under $20 brand new, not
worth mucking around with the old one.

 

Hi Matt: Water comes in through the air vent/cowl and sometimes gets
trapped at the base of the motor, which eventually rusts the motor shafts
and causes the howling, or ruins the motor. There is a rubber heater tube
that is designed to dry the motor, but this doesn't always work. I
documented the procedure on a 1985 740 I owned, along with some possible
aftermarket sources.

http://cvolvo.com/Central/Repair/740.html

Good luck... Cam

--
Cameron Price Newington, Ontario, Canada
http://cvolvo.com
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