Behind dash knocking thunking?!?

Trippen Out

Trippen Out

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As the title says. the there is a clicking/thunking/knocking sound behind my dash when i start my car. sometimes it would do it for a minut or so others it wouldnt stop till i shut the car off. I really cant think of anything behind the dash that would do that.

I wondered if it was the blend door. Do they go through some process when you start the car? Its been happening for a now. It has finally goto the point where its really annoying now. I'll just turn the radio up but id like to figure out. I don't really wanna have to pull the dash if i dont need to know what i mean.
 
I'm guessing your car is a 1st gen? 96?

Its the blend door actuator worm gear and ring gear jumping on themselves. Mine did it. I figured out a system.... turn your temp all the way to cold before you shut your car off. When you turn it on, it clicks a lot less.

Not as easy to fix as on a gen2

I replaced my actuator when I changed out my dash, and it made no difference. Some have said the pivot point on the heater box wears out and egg-shapes makes something out of alignment or hard for the little electric motor inside the actuator to turn. I took my old actuator apart and it was perfect.
 
If you want it to stop fast, turn the heat up to 82 and when you feel heat coming out the bottom (floor), little by little, start turning the temp back down and by the time you hit 74, it should have stopped by then. You can go ahead and set it where you want it but that will get it to stop the fastest.
 
NoLimit95 said:
If you want it to stop fast, turn the heat up to 82 and when you feel heat coming out the bottom (floor), little by little, start turning the temp back down and by the time you hit 74, it should have stopped by then. You can go ahead and set it where you want it but that will get it to stop the fastest.
Click to expand...

yea i think i saw you post that in one of the other threads i replied in. I also saw that it might not be the blend door its self. but something that was over bored or something.
 
I see several places that list a Blend door Actuator for the Gen 1
Rockauto:
1993 LINCOLN MARK VIII 4.6L V8 :
Heat & Air Conditioning : Heater Blend Door Actuator
MOTORCRAFT Part # YH1768
Blend Door Actuator
$33.99
1 In Cart

Is this the infamous no longer available blend door motor for the First Gen?
 
davidm said:
I see several places that list a Blend door Actuator for the Gen 1
Rockauto:
1993 LINCOLN MARK VIII 4.6L V8 :
Heat & Air Conditioning : Heater Blend Door Actuator
MOTORCRAFT Part # YH1768
Blend Door Actuator
$33.99
1 In Cart

Is this the infamous no longer available blend door motor for the First Gen?
Click to expand...

yea i saw a few places that sell those parts. im just waiting for some confirmation that those are indeed what is needed to fix the issue. in one of the links i posted above someone else had the same issue and replaced the actuator but that wasnt really the problem.
 
davidm said:
I see several places that list a Blend door Actuator for the Gen 1
Rockauto:
1993 LINCOLN MARK VIII 4.6L V8 :
Heat & Air Conditioning : Heater Blend Door Actuator
MOTORCRAFT Part # YH1768
Blend Door Actuator
$33.99
1 In Cart

Is this the infamous no longer available blend door motor for the First Gen?
Click to expand...

I would be careful of any that say they fit a 1st gen. At my work we bought one from Factory Motor Parts that said it fit 1st gens. It looked right in the pic, but when we got it, it wasn't the right part. This was for a customer's 96. I ended up pulling one out of my parts car to fix it.
 
It's just the gear that is stripped. I deal with it for maybe 2 min and then it's over and I choose not to get that much involved to make the sound go away. I'm not selling the car to anyone so, it's what I have to deal with until the wheels fall off. If I had known what I know now, I would have taken so many more parts off the 93 and 94 I had out back. Neither of them clicked when it was cold. Never heard that noise until a year after owning the 95
 
There are two possibilities.

The first one is that the plastic gears in the actuator itself are stripped. They put grease on the gears and eventually it causes them to break.

The second and worse possibility is that the square arm coming off of the actuator has stripped the hole it goes into. If that is the case then the repair is much more involved but fixable.

I replaced the actuator in my old 96 back in 2004. The gears in it were stripped and made the noise when the car came on as it was trying to move the blend door to the proper setting.
 
NoLimit95 said:
It's just the gear that is stripped. I deal with it for maybe 2 min and then it's over and I choose not to get that much involved to make the sound go away. I'm not selling the car to anyone so, it's what I have to deal with until the wheels fall off. If I had known what I know now, I would have taken so many more parts off the 93 and 94 I had out back. Neither of them clicked when it was cold. Never heard that noise until a year after owning the 95
Click to expand...

I keep trying your trick but it fails for me.

marked8 said:
There are two possibilities.

The first one is that the plastic gears in the actuator itself are stripped. They put grease on the gears and eventually it causes them to break.

The second and worse possibility is that the square arm coming off of the actuator has stripped the hole it goes into. If that is the case then the repair is much more involved but fixable.

I replaced the actuator in my old 96 back in 2004. The gears in it were stripped and made the noise when the car came on as it was trying to move the blend door to the proper setting.
Click to expand...

if its the worse possibilitiy. what is the "hole" and how do you fix it?
 
Interesting development or possible fluke i dont know.

went behind the glove box to snip the head light warning wire. while back there my friend noticed that a little "pull cord" like device that appears to open a flap for the defrost on the passanger side is broke off and dangling there. also it seams as if moving a few things around back there has cuases the thunking to stop all together. not sure what the deal is at this point.

any ideas on the defrost flap cable deal :)

edit:

i take that back its still thinking but only does it for a few seconds and stops. so i have no clue whats up with this ish.
 
Here's a pic of the hole the actuator goes in on a 96.

thermostat 004a.jpg
 
I would be removing the actuator to examine first to find out the exact problem before removing the entire dash.
 
Warm the car up before you go somewhere, start with the temp on cold, and move up a degree or two, every 3-5 minutes. If it clicks, just back it off a notch or two until it shuts up, wait, and advance it again. I do that with mine and I can take it up to max heat (90 degrees I think?) w/o any clicking. Now if you shut the car off it will click til it is turned down to somewhere in the 70's on temp. Did this until I swapped dashes. Replaced actuator, still clicked in the cold but not as loud, and went away quicker.
 
what pisses me off is i dont even have the hvac stuff turned on and it clicks. kind of scares me that you swapped out a dash and replaced the actuator and it still did that. what peice did you not replace.

personally ill sell the damn thing if i cant fix it. i love my 96 and i can take most of my work off the car and put on a new one. except for the valve kit because the next one i get is a 98 lsc with no moon roof.
 
Turn your hvac temp all the way down before you shut it off. It shouldn't click until you turn the heat on. If you turn the heat one before car is at opperating temp it will click.
 
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