Weird noise from inside!

I have a 1998 Dodge Mini-van. It has about 150,000 miles on it, but we
take care of it and it is still good transportation.

Today, something new and weird. When I first start the van there is a
knocking noise on front passenger side down near the floor. It just
knocks a few times like someone is at the door and then it goes away.
A couple times it did it on and off for a while, but mostly it is done
within 30 seconds. It sounds like it is from inside the cabin, maybe
from the ventalation?


Anyone have any ideas?

Thanks

Noises are hard to answer on line. It sounds to me like you arent sure if
it is engine related or something inside the vehicle. Try to isolate the
problem by turning the key to the run postion before starting it. If the
noise continues with the key off I would say it is possibly an HVAC
actuator motor/door binding.

Glenn Beasley
Chrysler Tech

damnnickname wrote:
> Noises are hard to answer on line. It sounds to me like you arent sure if
> it is engine related or something inside the vehicle. Try to isolate the
> problem by turning the key to the run postion before starting it. If the
> noise continues with the key off I would say it is possibly an HVAC
> actuator motor/door binding.
>
> Glenn Beasley
> Chrysler Tech

Thanks for the reply. I will try that. I'm reasonably sure it is not
engine related, though. In fact, your suggestion is exactly what I was
thinking of. So, what do I do about it?

Oh, and also, if the air controls are not changed, let's say they are
set on a mix between floor and dash, would you get this actuator
motor/door binding? I figured that would only happen when you changed
your settings to, say, all floor air flow.

Thanks again for your help.

Actuators are "powered" by engine vacuum. Some systems have large
reservoirs of vacuum, others very little for this use. Try running the
engine for a few minutes, then shutting it down ; Then try moving the vent
controls. If that is the problem, either ignore it or lubricate the hinge
point.
"shacky" > wrote in message
ps.com...
>
> damnnickname wrote:
>> Noises are hard to answer on line. It sounds to me like you arent sure if
>> it is engine related or something inside the vehicle. Try to isolate the
>> problem by turning the key to the run postion before starting it. If the
>> noise continues with the key off I would say it is possibly an HVAC
>> actuator motor/door binding.
>>
>> Glenn Beasley
>> Chrysler Tech
>
> Thanks for the reply. I will try that. I'm reasonably sure it is not
> engine related, though. In fact, your suggestion is exactly what I was
> thinking of. So, what do I do about it?
>
> Oh, and also, if the air controls are not changed, let's say they are
> set on a mix between floor and dash, would you get this actuator
> motor/door binding? I figured that would only happen when you changed
> your settings to, say, all floor air flow.
>
> Thanks again for your help.
>

"shacky" > wrote in message
ps.com...
>
> damnnickname wrote:
> > Noises are hard to answer on line. It sounds to me like you arent sure
if
> > it is engine related or something inside the vehicle. Try to isolate the
> > problem by turning the key to the run postion before starting it. If the
> > noise continues with the key off I would say it is possibly an HVAC
> > actuator motor/door binding.
> >
> > Glenn Beasley
> > Chrysler Tech
>
> Thanks for the reply. I will try that. I'm reasonably sure it is not
> engine related, though. In fact, your suggestion is exactly what I was
> thinking of. So, what do I do about it?
>
> Oh, and also, if the air controls are not changed, let's say they are
> set on a mix between floor and dash, would you get this actuator
> motor/door binding? I figured that would only happen when you changed
> your settings to, say, all floor air flow.
>
> Thanks again for your help.
>
The next time you get in the vehicle move the temp control knob to see if it
does it, if it doesn't, put the a/c on and then hit the recirc button to see
if the noise is there.

Glenn

"George Jaynes" > wrote in message
. ..
> Actuators are "powered" by engine vacuum. Some systems have large
> reservoirs of vacuum, others very little for this use. Try running the
> engine for a few minutes, then shutting it down ; Then try moving the vent
> controls. If that is the problem, either ignore it or lubricate the hinge
> point.
> "shacky" > wrote in message
> ps.com...
> >
> > damnnickname wrote:
> >> Noises are hard to answer on line. It sounds to me like you arent sure
if
> >> it is engine related or something inside the vehicle. Try to isolate
the
> >> problem by turning the key to the run postion before starting it. If
the
> >> noise continues with the key off I would say it is possibly an HVAC
> >> actuator motor/door binding.
> >>
> >> Glenn Beasley
> >> Chrysler Tech
> >
> > Thanks for the reply. I will try that. I'm reasonably sure it is not
> > engine related, though. In fact, your suggestion is exactly what I was
> > thinking of. So, what do I do about it?
> >
> > Oh, and also, if the air controls are not changed, let's say they are
> > set on a mix between floor and dash, would you get this actuator
> > motor/door binding? I figured that would only happen when you changed
> > your settings to, say, all floor air flow.
> >
> > Thanks again for your help.
> >
>
>
Chrysler Hasn't used vacuum reservoirs on the vans since 1995. They are all
controlled electrically.

Glenn Beasley
Chrysler Tech

A very helpful fellow wrote me an email and pinpointed the problem.
Thought I would wrap up this thread with the info. Behind the glove
compartment is a door and actuator that opens and closes the door and
either lets the air in the cabin recirculate or bring in fresh air.
When the car starts it operates the actuator and over time the gears in
it strip and the knocking noise is the gears.

It is fairly easy to take off. I took it in to my Chrysler dealer and
have a replacement ordered at the cost of about $53.

So, that weird knocking noise when I started the van; the recirc
actuator.