CCU or Blower squealing

[szvook]

Ok, so finally my car has something that failed to work. My CCU or blower started squealing/whistling two days ago (although, I heard it a year ago, but it went away) and today no air is blowing through the vents at any speed: hot, cold, A/C or windshield defroster. Can it be the fan bearings that made the squealing/whistling noise? I don't think it's the blower regulator. Maybe its just a fuse, but I think it's the blower that had it.

 

[mistermiata]

Funny you should bring this up....my 94 with 105k miles just started an annoying noise when the fan is on. Very faint click/whistling, almost like something (maybe a leaf or debris) is caught in the fan.

Hope its not the bearings like in your car, Steve!

 

[szvook]

Very faint click/whistling, almost like something (maybe a leaf or debris) is caught in the fan.

I didn't hear any clicking, just a whistling sound. And no crackling or moaning noises like here -

[video=youtube;s_DDk1s9rB8]http://www.youtube.com/watch?v=s_DDk1s9rB8[/video]

 

[gsxr]

A squeak or squeal, which eventually turns into zero airflow, is almost guaranteed to be a failed blower motor. When it's just making noise, you may be able to lube the bushings with ATF and squeeze another few months to a year out of it (if the brushes have any life left). But when it stops working, that usually means the brushes are worn out. A new blower motor should cure it. Remember the 94-95 blowers are different than the 86-93. Replacements run around $200-$300 plus about an hour labor. It's a medium DIY that requires removal of all the windshield trim and the entire windshield wiper mechanism. Feel free to check the fuse, but a fuse won't cause squealing noises...

 

[szvook]

Thank you.

Btw, are there any plastic clips or panels underneath that might need replacement?

 

[Jelmer]

This is something that's also coming up for me, soon. I found this guide: http://www.peachparts.com/Wikka/W124BlowerMotor which seems pretty decent.

 

[500ESpain]

Seems an epidemic. The blower on my 320CE started squealing yesterday.

 

[gsxr]

The Fruit forum writeup (link above) is pretty good. I would recommend NOT buying the aftermarket bare motor and trying to swap the plastic fan cages, they are fragile and difficult to remove/install. Just buy the complete motor+fan assembly. Mercedes only sells the complete assembly, btw. There aren't really any parts or clips which always need replacement, but there is a lot of little hardware involved - be careful not to lose any, and be careful when tugging on the platsic clips.

BTW - the procedure shown is applicable to 86-93 models without dust filter. The 94-95 with dust filter is similar, but not identical.

 

[gerryvz]

Here's another pretty good link to the procedure. I did the blower + regulator replacement on my wife's E320 wagon earlier this year. It's not horrible but as Dave says there are quite a number of small parts that extraordinary care must be taken to not lose.

You can get a good quality blower (with motor) part on the aftermarket (AutohauZ). Indeed it is advisable to replace the motor + cage as one unit rather than trying to retrofit an old cage on a new motor. Just spend the moderately extra $$$ and get the entire unit as a whole. And be cognizant that the regulator (a fairly expensive part) is often the culprit, and is a good part to replace at the same time "while you're in there" as it's only about 15 minutes of extra labor to do so.

http://www.davebarnhart.com/mb300e/Blower/Blower1.htm

Cheers,
Gerry

 

[jano]

The blower motor was one of the first DIY repairs I've done in my life, and I survived, followed the peachpart's wiki and got the replacement motor from autohausaz. As Dave said, procedure is slightly different for the '94 models, but hey, *I* figured it out

Just a note of caution, watch out for those insanely deadly little rubber-trim-keeper-in-place-spikes. They are extremely sharp and pointy.

 

[mistermiata]

Steve (and others that have experinced this problem),

Where does the noise seem to be located? Mine seems to be on the driver side of the dashboard, almost directly behind the gauge binnacle....

Still trying to determine if mynoise is the blower motor or some debris in the fan? My noise is also more prevalent in the "Auto" mode, less prevalent in low fan mode, and not present in high fan mode.

Andy

 

[gsxr]

Andy, the typical blower squeak/squeal noise is located from the center of the dash. It's easy to prove if it's the blower: press the "O" button on the controls to turn it off, and you can hear the noise slow down and stop. Turn it back on and the noise should return. It's usually present at low fan speeds and may go away at medium or max fan speed. All these signs point to a blower motor in need of lubrication or replacement.

 

[mistermiata]

Thanks Dave......that pretty much sums up my situation. Guess I will add it to list of things to do in the near future.

 

[gerryvz]

It's not a horrible job -- can easily be done on a weekend afternoon.

 

[szvook]

Ok, I got the motor and regulator ordered through my shop and we’ll test if the regulator might be the culprit - the regulator can be returned with no problems, if it's not the culprit. And yes, the whistle/squeal was coming from the front and when the climate control was turned off or the speed was set higher, the whistle/squeal went away.

Btw, were all 1992 500E without filters for CCU? My shop told me that some 1992’s did come with filters.

 

[gerryvz]

No, they are mistaken with regard to the cabin filters. They are off by a long way.

Only 1994 and 1995 model year W124s came with cabin filters. 1993 and earlier cars did not (though there is an aftermarket retrofit kit available, which 2Phast has documented).

Cheers,
Gerry

 

[gsxr]

Gerry is correct on the filters - only 94-up model years, period.

If the blower spins at all and will vary the speed, the regulator is fine. When the regulator fails, you either get zero fan speed, or a fixed speed that never changes.

 

[szvook]

No, they are mistaken with regard to the cabin filters. They are off by a long way.

That's what I thought as well, thank you for the confirmation.

 

[Hollybrook]

I think I remember somebody writing up instructions on adding a cabin filter to pre-94 cars. Certainly not factory installed, but a shop might have seen a modified car...

 

[gsxr]

There was a writeup on adding the factory 94-95 filters to an 86-93 heater box. However this is not recommended, as the procedure shown will cause the main air flap to not be able to close completely, which will impact AC performance on hot days. If you have an 86-93 car and want to add filters, the aftermarket external JR filters are the best way to go. Unfortunately, they are bloody expensive to import to the USA. JR claims they need replacement every year or so, but they can be used for years, and washed out if necessary.

 

[Jelmer]

Pardon my ignorance, but what's the improvement one would gain by adding these filters?

 

[maw1124]

Also, what's the price and function of the "regulator" folks are discussing here? Pardon my ignorance as well. I'm kicking myself for not doing this the first time I heard the noise. Now it's the holidays, I need the car, and... you folks know the rest.

 

[gerryvz]

Jelmer,

In reality, nothing. These cabin filters are rather thin filter material and don't contain charcoal or anything else that is designed to really clean the air, eliminate odors, etc. as is the case with the W210 and W140 cars, which have much more robust cabin filtering systems. I think the purpose really is just to keep airborne dirt and debris (dust) out of the HVAC system and cabin air. But, I don't really see that particulates are a huge problem with cabin air. The filters have always seemed to me to be more an afterthought than anything else. Just my opinion though.

If you have a pre-1994 W124, you're really not missing out on much if anything.....

Cheers,
Gerry

 

[gerryvz]

Also, what's the price and function of the "regulator" folks are discussing here? Pardon my ignorance as well. I'm kicking myself for not doing this the first time I heard the noise. Now it's the holidays, I need the car, and... you folks know the rest.

The regulator is the mechanism that directly controls the speed of the fan. It has an array of splines that stick up into the airflow and based on the ACC hard-programming and the user's settings (and interior temp sensor) on desired interior temp and fan speed, it variably adjusts the fan speed accordingly. The regulator is, technically (electrically) a resistor that connects to the fan via two leads (red and blue, if I remember correctly). When the regulator goes out, the ACC system & driver essentially lose control of the blower fan speed, so it typically defaults to a "no-op" or a "full on" setting with nothing in between.

I had my regulator die earlier this year in my wife's 1995 E320 wagon on the drive home from Phoenix/Tucson to Houston, and I had no fan. I could still control temp but it had to rely on the little airflow provided by the car moving at freeway speeds to actually move air through the system (luckily it was in January, so winter time). The regulator is also known as the "porcupine" because of its array of splines. It sits directly BELOW the fan and thus the blower motor/squirrel cage fan assembly must be removed to access the regulator. I recommend replacing both at the same time simply because you're already doing the labor to get in there. Once done, it's good for another 10-15 years.

When buying regulators, be wary of aftermarket products. The Benz regulators are the best, but also the most expensive (and they differ between earlier and later cars). The factory units list at well over $400. You can get aftermarket units from Behr or KAE; the KAE regulators are not a good idea in terms of quality so if you can get a Behr for your car, it's highly advised. The Behr units should be available for $150-200.

Cheers,
Gerry

 

[maw1124]

Got it. Thanks, Gerry. The guys are German Sarasota have the car now. Hopefully they can work some magic and get both in today. Parts are ordered. I'll see which ones they ordered.

Happy Holidays,

maw

 

[gsxr]

The filter primarily keeps the evaporator clean. The evaporator fins can get pretty gunked up with crud on pre-94 cars without filters. The 94-up factory filters are extremely effective, when I've opened those up the evaporator always looks shiny & new. Pre-94 evaps can vary from a little dusty to significantly plugged up. While you have the blower motor out, this is a good time to clean the fins if necessary.

Adding the JR filters to a pre-94 car is sort of closing the barn door after the horse is stolen, as they would have been more effective if installed when the car had zero miles. But if the evap is clean, they will help keep it that way, or at least slow down the gradual dirtification. I have the JR filters on my '87 and '92 cars. Our other cars are 94-up with factory filters.

If the evaporator ever fails on a pre-94 car, that would be the time to upgrade to the 94-up heater box assembly, as the heater box has to be removed to replace the evaporator. Might as well swap in the later style while it's apart. They're obscenely expensive new ($3k wholesale!), but you can get them used for a couple hundred bucks and swap in a new evaporator before installing. Since this is a 20-40 hour job, it's not something you'd ever consider unless the evap failed and could not be sealed chemically.

 

[szvook]

Issue fixed, it was the blower motor. Btw, the zero airflow at all speeds was actually a loose cable underneath the console. Once the cable was reattached, the old blower motor did work, but still with the squealing/whistling noise. We did lube the old motor and gave it a shot, but is still whistled. A new Behr motor went in and all is back to normal. I didn’t replace the tray for the motor, as it looked and felt good without any hint of falling apart.

 

[gerryvz]

Well, that's good you got it fixed. So I take it they didn't bother with the regulator then, just the fan/motor assembly. If I may ask, what was the amount (hours) of labor they wrote up for that job on the blower motor?

Also, what is the "tray" for the motor? Not sure what you mean by that term. I wonder how that cable came loose.

 

[szvook]

Well, that's good you got it fixed. So I take it they didn't bother with the regulator then, just the fan/motor assembly. If I may ask, what was the amount (hours) of labor they wrote up for that job on the blower motor?

Also, what is the "tray" for the motor? Not sure what you mean by that term. I wonder how that cable came loose.

We left the regulator as is, for now, as it didn’t seem to show any issues. My tech did the job in 1 ¾ hours, which included looking for the loose cable. Maybe the cable got loose from all the track days, with launching the car hard off the line, over and over. There was no break in the cable or exposed wires, just got loose.

The tray is the housing where the motor resides, my tech told me that sometimes they get quite brittle and can break. He has seen one or two ever break and on cars with higher millage.

Btw, the new motor came with new squirrel cages attached.

 

[gerryvz]

Maybe the cable got loose from all the track days, with launching the car hard off the line, over and over.

Ahh, could be. Or it could be the "revenge of 400Eric" where he slyly disconnected the cable to spite you

Btw, the new motor came with new squirrel cages attached.

Yep, that's how they come when you order them. I don't recommend retrofitting old squirrel cages onto new motors (or vice versa) -- best just to get the whole she-bang.

Good show!

Cheers,
Gerry

 

[szvook]

Or it could be the "revenge of 400Eric" where he slyly disconnected the cable to spite you

I wouldn't put it past him...I have been leaving my hood open for cool down while watching the races and leaving Eric alone next to my car.

I don't recommend retrofitting old squirrel cages onto new motors (or vice versa) -- best just to get the whole she-bang.

Ditto.