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73 450sl
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Discussion Starter · #1 ·
Well I've been looking at all the parts places and have come to the conclusion that this part is in the unattainable area of parts.
I did google the part number and found out that I can send the part back to mercedes and they can remanufacture my stock one.
I checked it in 150 plus water and it didn't close so I'm guessing it's stuck open or bad.
Rowdie said he cleaned his out with carb cleaner anyone else have a solution on how you cleaned yours out to get it to work.
 

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500SLC #2624. Black on Black.
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Well I've been looking at all the parts places and have come to the conclusion that this part is in the unattainable area of parts.
I did google the part number and found out that I can send the part back to mercedes and they can remanufacture my stock one.
I checked it in 150 plus water and it didn't close so I'm guessing it's stuck open or bad.
Rowdie said he cleaned his out with carb cleaner anyone else have a solution on how you cleaned yours out to get it to work.
Brad, it would really help if you filled out your profile, so we know what year and model and can better identify the correct part. A location would help too, so we know where is convenient to find one!
 

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Dad recently bought a new one from MB Classic. was very pricey $300ish if i remember correctly.

I may have one if yours compatible with a 1972, you didnt give any year, make, or model. info helps.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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Well I've been looking at all the parts places and have come to the conclusion that this part is in the unattainable area of parts.
I did google the part number and found out that I can send the part back to mercedes and they can remanufacture my stock one.
I checked it in 150 plus water and it didn't close so I'm guessing it's stuck open or bad.
Rowdie said he cleaned his out with carb cleaner anyone else have a solution on how you cleaned yours out to get it to work.
Soak the whole thing in solvent or even a soapy solution using dishwashing soap. I did both of those and also cleaned it in an ultrasonic bath. One of mine works well, the other moves, but does not close at the correct temperature. If it closes slightly higher than 150F, it should still be OK - Hard to measure anyway and they are slow to move. I put a hot air gun on mine and used an IR thermometer. Seemed easier than trying to use hot water.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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This auction ended May 11 but I sent the seller a question about the one we need. BOSCH IDLE CONTROL VALVE ICV FOR IMPORTS | eBay
Not the greatest feedback.
A 3-wire aav (aka IAC) off a mid 90's Saab or Volvo has been used instead of the thermostatic original (barri on Peachparts). This allows the idle air to be adjusted from the dash. I was going to do this mod, but then found a good AAV that seems to be working well. There are a number of these motor driven valves that would work, but it would be best to search the wreckers to find one with closest hose sizes and nozzle orientation. No such yards up here :( One of the ones in teh above auction "might" work.
 

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1973 450 SLC
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124 Posts
I cleaned it with Brake cleaner probably 1/2 a can. Then I used a heat gun to heat it up and once it moved I threw it in a bucket of ice water. Rescued it and thru the heat to it again. Repeated it a dozen times. I would spray it if there was any residue on the sliding cylinder. Soon the AAV behaved like it was designed.

Use gloves and pliers for protection. Keep the bucket of ice water several steps away from the heat gun.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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One thing I forgot to mention, was that if after cleaning, the AAV moves OK, (but does not close at 150F) it is possible to squeeze the bulb so as to increase the size of the indentations in the bulb. This should make the valve close at a lower temperature (There was a thread year about this several years ago).

I tried this but did not have great success, but it should work.
 

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73 450sl
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Discussion Starter · #9 · (Edited)
Ok updated car and location,
Thanks for all the suggestions. I've had it soaking in bp blaster for the last two days. Going to check to see if it has done anything yet. Will do some of the other cleaning solutions on it too.

Just took another look at Rowdies deconstruction of the valve. Has anyone tried to press the center section out and then remove the plunger to clean it?

I may give this a try as I have a press and the wild hair to just go for it.
 

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Outstanding Contributor, Vintage Moderator
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
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I have been considering visiting my somewhat local 1973 parts car that was complete when I started pulling parts from it. PM me a price you'd be willing to pay for a used one and I will make an offer.

Also. I don't know where it is or what the AAV looks like, so any pictures would be helpful. Hopefully I won't NEED to learn this for my car, but I'm sure it will be good to know.
 

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73 450sl
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Discussion Starter · #11 ·
Not to up on posting pic's just yet. I do know that it is on the front of the motor just above the distributor. the cold start valve, idle adjust screw and AAV all sit by each other. The AAV has the one rubber 90 degree pipe coming out on the right side and another one a little higher on the left side that goes to the throttle body. It is held in place by two 8mm bolts.
 

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Outstanding Contributor, Vintage Moderator
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
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From your desxription, I think I've got one of these in a box in my garage, from a fellow member's 1975 SLC. I will give you an email address to send him a few bucks via paypal. Let me know what you'd like to pay, and I'll give you they guy's paypal email and a picture of the part(s) I have. Then send me verification that you sent him funds and I will ship to you.

Just let me know. I think I should be able to ship Monday or Tuesday.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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Also. I don't know where it is or what the AAV looks like, so any pictures would be helpful. Hopefully I won't NEED to learn this for my car, but I'm sure it will be good to know.
Believe me, if you own a 73 450SL (or any D-Jet) you WILL need to find out where the AAV is ;)

This may help:
 

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Also, The rubber hose going to the AAV is critical. After this issue is cleared up, one of the test will be to squeeze the hose close to see if it affects the engine. If the hose is hard or leaking it will be difficult to diagnose future problems.
 

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73 450sl
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Discussion Starter · #15 ·
I had to go get new hoses as the ones on the car broke when I tried to remove them. Peanut brittle comes to mind.

I sent MBGraham and Rowdie a write up on how I cleaned up the valve. It comes apart very easily with a press which makes cleaning it very fast and effective.

I hope MBGraham can show the dis-assembly with pictures as I do not have access to a camera to have photographed the process when I cleaned mine today.
 

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That was slick! We have thought the AAV could be pressed out... but you did it Congratulations!!! Did you press from the Top or the bottom?
 

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1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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Why not post the method so all can understand?
We can wait for visual aids.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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Why not post the method so all can understand?
We can wait for visual aids.
Don't know if Brad is around, but this is how he described it to me:

Re: AAV cleaning
On my press it goes down from the top. I had the AAV with the top vent pointed toward the floor and supported by two plates with a 45 degree v cut out which was just enough to catch the shoulder above the lower vent hole.

Yes the socket went over the brass nub and then I just pressed the whole thing out of the outer case.
Using your pic Rowdie, picture below is how I envisage doing it. May use something other than the V-plates for bottom support, depending on what I happen to have amongst junk.

BTW, I did once try something like this, but without hydraulic press. Used a hammer but it wouldn't budge!!

Once separated and cleaned, next trick may be how to set it so that it will close at 150F. It would be best if this could be done in one step without dismantling a second time.
 

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1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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That is the way I thought it would work.
Thanks Graham. My spare doesn't close @ 150 either.
 

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Discussion Starter · #20 ·
MBGraham you have it correct. The hardest part is the vent tube. With the support plates I had to leave a gap so it would press out.
That is why the V shape worked so well as I could get 4 points of the shoulder supported.
Then it was easy to press the top back in first. Then flip it over install the spring, plunger and the bottom with the viscus fluid and press it back down.

One more piece of advise is to mark with a sharpie which way the vent tube is angled. Forgot to do this and had to semi put together on the motor to get the correct angle.
 
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