74 450SL - Cold idle hi/low/hi/low cycling - Mercedes-Benz Forum

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post #1 of 4 (permalink) Old 02-20-2012, 08:39 PM Thread Starter
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74 450SL - Cold idle hi/low/hi/low cycling

Hi all, brand new owner of this vehicle. 116K miles.

After it's warm, idles well, but when starting, it idles hi/low cycles every 1-2 seconds. Seller mentioned idle control valve. I have a feeling this is a well-known symptom.

I appreciate any responses and thank you in advance!

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post #2 of 4 (permalink) Old 02-21-2012, 08:33 AM
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Head over to the 107 forum and check the sticky for Encyclopedia Germanica.

Tell tale signs of an Aux. Air Valve
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post #3 of 4 (permalink) Old 02-29-2012, 10:48 AM
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Sounds like the air valve to me. I think they are getting harded to find (and more expensive). Anyone had any luck freeing up sticky valves?
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post #4 of 4 (permalink) Old 02-29-2012, 03:20 PM
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Originally Posted by Peoria Benz View Post
Anyone had any luck freeing up sticky valves?
Can't say I've ever had a sticky valve, but if memory serves, a good soak in acetone (nail polish remover) followed by another one in WD40 or other penetrating oil does the trick. Try a general search in this forum - I seem to remember hearing about this before...
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