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Has anyone ever had a leaking Washer Fluid tank / pump?

8K views 25 replies 12 participants last post by  silvercar 
#1 ·
I have a drip coming from either the washer fluid reservoir or the little pump that drips about once every 30 seconds.

I can't pinpoint where exactly the leak is as it's a ***** to get to either component.

Just wondering if anyone else has had this problem? :(
 
#2 ·
Windshield Washer Reservoir Leaking:

I have heard of this happening before. A lady in our smart club had rats chew through both the reservoirs in her two smart cars parked in her garage. She was able to get her insurance to recompense her for part of the replacement costs. Freezing of the solution and vibration as well as excessive heat causing the plastic reservoir to degrade are also possibilities. In any event, replacement is the only way to repair the reservoir, but I have also read where someone was able to patch theirs.
 
#9 ·
Ask and thou shall receive :D

Windshield Washer Reservoir Repair​

(This was another member's fix )​



The washer reservoir is indeed removable without having to disassemble the entire front end. There is a nut right behind the wiper plug. Used a small 10mm wrench to work the nut off. I also removed the bolt in front of the wiper motor to be able to move the motor ever so slightly so I could work the reservoir off the bolt.

The other connection point is a little harder to get to. If you pull the washer pump out of the reservoir and look below and to the right of it, there is another nut sticking out. I didn't have a swivel socket, but it looks like if you did you can access the nut from above. For me, I had to remove the bolts that hold the plastic cover on the underside front and stick my arm up with the 10mm wrench. It's tight but easier to get off than back on.

After the nuts are off, push the bottle to the right to disengage it from a plastic stud on the air box and carefully work the bottle out of the opening. It is tight but does come out.

My reservoir had a small crack or hole at the point where the bottle is formed together from the factory. It was at the spot where a hose from the radiator goes across the bottle. Don't know if it was a factory defect or if the heat from the hose caused the bottle to separate.

To repair my crack, I used a 35w soldering iron to gently heat the reservoir plastic and seal the pieces back together (chief used a piece of Eternabond :D). Additionally, I applied a couple layers of plastic from an empty gallon jug of washer fluid and melted and worked the plastic together, welding them to the reservoir.

After the welding, I ran the reservoir bottle under cold water to harden up the patch.

The bottle went back in easier than it did coming out, but I did have to reach up from the bottom to push the small radiator hose up that goes into a groove in the front of the bottle.

After the reservoir bottle is back in, put the nuts back on, push the pump back into the hole in the reservoir bottle, fill with fluid, and don't forget to plug back in the wiper motor plug.
 
#12 ·
Hello everyone, I'm a new member here, my first post, thanks for all of the great information.

I just purchased a 2008 convertible with 14,000 miles. I have it at my local smart/Mercedes dealership for a post-purchase inspection and general check-up and to check for the interior sensor alarm going off intermittently.

The car required an update and decal for the traction control(?) (no charge) and I needed to have my spare key reprogrammed.

They found a leaking washer bottle, estimated cost to fix was indeed $450.00.

Along with $300.00 estimate to replace the spark plugs and a $1,000.00 estimate to replace the microwave unit and a harness in the alarm system.

The charge to program the key was $60.00.

Quite an expensive little car to fix, luckily I can do most of the work myself.
 
#13 ·
Wow! and exactly why did they want to replace the spark plugs? The factory interval is 30K, you're only at half that. Plus, you can get the Iridium replacements which will go about 50-60K for 1/2 what the dealer wants for the factory copper...

As for the interior alarm, I'd just keep it off...:)
 
#15 · (Edited)
Thank you dogbreath, I spent a lot of time lurking on the forum and researching vendors and I appreciate your recommendation.

Wow! and exactly why did they want to replace the spark plugs? The factory interval is 30K, you're only at half that. Plus, you can get the Iridium replacements which will go about 50-60K for 1/2 what the dealer wants for the factory copper...

As for the interior alarm, I'd just keep it off...:)
I asked the service writer the same question about plug replacement at 14k miles. The answer was "because they are 6 years old". While I don't agree 100% with that reasoning, it does have some validity in that I've seen plugs get seized in engines with extended plug service intervals. If you're going to take them out to prevent them from seizing up, then you might as well replace them I suppose. But $300.00 seems crazy expensive for 3 plugs.

For now I will just disable the alarm or try to remember to hit the switch before I exit the car. I'm the type of person that if a part or accessory is on the car I want it to work. I'll do some more research and see what happens. The service writer said that there was no Mercedes considerations for the price of the repair at this time, but that I should check back. There is apparently a service bulletin issued. In all of the research I've done on the alarm, this was the first time I've heard of an updated alarm wiring harness. I can understand that electrical parts can fail, but an updated harness seems like a design issue. Parts were quoted at $600.00 and the labor at $400.00. I've seen the microwave unit priced at around $200.00 from Mercedes, so that means the harness is $400.00.

I already had the console removed before dropping off the car as I had replaced a cracked shifter sleeve. The microwave unit is right there on the floor, but it still might require removing the seat and carpet to replace the harness and could take a little time.

While the prices for repar seem expensive, the dealer has been nice to deal with so far. They even gave me a 2013 smart loaner to drive. I can feel quite a difference between the 2008 cabrio and the 2013 hardtop, it's much more refined it seems.
 
#16 ·
Why does it need both an ultrasonic sensor module AND a harness? Unless the harness and sensor module were melted together.
My 09 used to drive me crazy with false alarms. A smart center diagnosed a defective alarm module which they did not have in stock. They closed the next day, so the next smart center diagnosed a mal-adjusted tailgate alarm switch. They adjusted it. When I arrived home 4 hours later, the car would attempt to lock and then unlock. Could not lock the car. I dismantled the tailgate, unbent the grossly over bent microswitch actuator lever to the proper position and have not had a false alarm since. Apparently that was a common issue for some of the 08 and 09's.
It is a simple thing to check.
 
#17 ·
Why does it need both an ultrasonic sensor module AND a harness?
I'm under the impression that the Mercedes service bulletin told them to replace the microwave sensor and a harness. Perhaps the harness has been upgraded with extra shielding or a resistor wire or something, but that's just a guess. It could also be the sensor was upgraded and requires a different harness for installation. I'll try to get more information when I pick up the car.

My alarm will not sound if I turn off the alarm switch inside the car before locking the doors. It only misfires if I forget to turn off the motion sensor. I'm making the conclusion then that it's not a micro switch, but must be in the microwave sensor system somewhere. The alarm functions normally if I bypass (switch off) the motion sensor.

I'm thinking I'll buy a used microwave sensor that has a later production date than mine and see what happens.
 
#18 ·
Mine did that exactly as well. I used to turn off the motion sensor for about a year just like you did. The solution was the microswitch. Go Figure.
Are you coming to Outsmarting the Dragon this year? I'll bring my spare ultrasonic module for you to try. If not, I'll send it to you to try. I've not needed it since the microswitch fixed it.
Interested? pm me, I'll loan it to you, or sell it to you one.
 
#19 ·
If there is one thing I learned fixing cars for 30 years, it's that micro electronics can have a mind of there own sometimes. We're usually not informed of their basic programming either. One open micro switch could be ignored when the microwave sensor is disabled, but if the sensor is activated it could cause an alarm. Who knows.

Thank you for the offer of a tester unit, that is very kind of you. I will test the micro switches when I get the car back and let you know.

I think as these cars continue to depreciate and become more affordable to more people, forums like this will become invaluable.

Mercedes Benz North America, are you listening? If your smart cars get a bad reputation for unrealistically expensive repair costs, they will become even harder to sell here.
 
#21 · (Edited)
The Mercedes Dealers are so used to a clientele that takes pride in owning an expensive car to maintain. smart owners don't usually fall into that same category. We have a different kind of relationship with our cars. We love them but don't expect to spend a college educations' worth of funding to maintain them as a status symbol. After all, there is no MB star on the front, from the factory anyway.

I'm goin in for service, pass the lube. :D Forget the lube, It's going to hurt anyway.
 
#22 ·
I thought I'd post an update to the alarm issue.

I checked the microswitch in the tailgate and it functioned fine.

I located a used microwave sensor for $50.00 and installed it. So far, it hasn't false alarmed, and it will alarm when set and you reach into the car through an open window (I waited about 15 minutes, it wouldn't alarm immediately upon locking the car.). In hindsight, I had tried to set off the alarm by reaching in through the open window after locking the car and it never worked. I had just bought the car and thought I was doing something wrong setting it. That may be a clue towards diagnosing the intermittent sensor.

The dealer told me that I wouldn't be able to drive the car with the microwave sensor unplugged, this wasn't true. The car drives fine and the standard alarm seems to work with the microwave sensor completely removed from the car.

My original sensor was made the 28th week of 2007, the replacement sensor was made the 21st week of 2009. Hopefully in two years they figured out the problem and made the sensors better quality.

I took the old senor apart. It's a circuit board that has what appears to be an antenna on one side. It looks like the label should face down in the car, towards the carpet. It would be possible to put it in upside down if you weren't careful.
 
#24 · (Edited)
Woody14619

I found someone parting out a smart on craigslist, contacted them and made an offer for the sensor and a few other items.

There are a few used microwave sensors on eBay, some accepting Best Offer. Average asking price is around $85.00 and I found some dealers selling them around $180.00 new.

Search for MDD Sensor, that's what's printed on the smart label on the controller so that's how they are being listed.

The production date is also on the unit, I'd guess newer is better.

P/N: A 451 820 01 10 / 004

(actual size 2.5 x 3.0 x 0.75 inches)

 
#25 ·
Just another piece of the puzzle. If your car is parked on a slope, and a heavy bus or in my case a train goes by, the vibration is enough to set off the alarm's tilt sensor.
I had the wheels off, the rear up on jackstands and the train went by shaking the ground enough to set off the tilt sensor that was tilted making it extra sensitive. It is the first false alarm I've had in several years. I used the disable button and had no more alarms the rest of the night while tilted up on jacks. A steep driveway could make the alarm sensitive to shaking more so than on level ground.
 
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