I did not know I even had one, but found that the driver's side valve cover vents to the idle valve via a valve (part number 1160900275). MB calls it a "starting Valve".
Tomguy on Peachparts tells me this is a PCV valve. It is a crankcase vent valve, but what concerns me is that it connects directly to the idle valve assembly. If more air passed than it was designed for, it would be similar to a stuck AAV or a vacuum leak on our D-Jet cars.
My shop manual and the one for W116s say that there is a 2mm orifice where my car has this valve. See pics.
Do other D-Jet owners have this valve (Item 98 in pdf)?
I did not know I even had one, but found that the driver's side valve cover vents to the idle valve via a valve (part number 1160900275). MB calls it a "starting Valve".
Tomguy on Peachparts tells me this is a PCV valve. It is a crankcase vent valve, but what concerns me is that it connects directly to the idle valve assembly. If more air passed than it was designed for, it would be similar to a stuck AAV or a vacuum leak on our D-Jet cars.
My shop manual and the one for W116s say that there is a 2mm orifice where my car has this valve. See pics.
Do other D-Jet owners have this valve (Item 98 in pdf)?
Yep, I have this and just replaced it a month or so ago. Makes a big difference in performance and starting. It was about $90 from MB with MBCA discount.
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My Mercedes keep me so broke, I can't even pay attention!!
Yep, I have this and just replaced it a month or so ago. Makes a big difference in performance and starting. It was about $90 from MB with MBCA discount.
Interesting! What made you change it? Was it something a mechanic or dealer suggested? It's not something that seems to come up when D-jet owners are asking about starting or performance problems.
Rowdie - seeing you have idle valve apart, can you see how it works? Would vacuum at idle suck it closed?
I put a clamp on and pinched the hose off, just to see if that makes any difference. It made no difference to rpm on cold start at idle, but will check again with engine hot.
If a 2mm orifice will do the job, I wonder how much better a $90 MB valve would work
Oops - different part in my post. My part was #89, the thing that looked like a PCV valve that is at the end of the hose from the valve cover to the start valve that Rowdie is showing. My valve got all gummed up and didn't seal up the back flow to the crankcase. I changed it because I was getting excess smoke out the exhaust.
Oops - different part in my post. My part was #89, the thing that looked like a PCV valve that is at the end of the hose from the valve cover to the start valve that Rowdie is showing. My valve got all gummed up and didn't seal up the back flow to the crankcase. I changed it because I was getting excess smoke out the exhaust.
I think 89 is the idle valve casting, is it not? And 98 is the PCV type valve that screws into that casting and is supposed to close when car has high vacuum such as at idle.
Rowdie's picture was of the complete idle valve assembly including the PCV type valve.
From what I can see, air comes into the passenger side valve cover from the air filter and finds its way through the engine to the driver's side. The car's vacuum pulls the air & fumes from the drivers side valve cover through the PCV valve and into the car's intake. The PCV valve should partially or fully close at idle and low rpm so as not to lose vacuum.
If the PCV valve sticks open, it would be like the AAV sticking open and could cause hot start problems and lean mixture.
Oops - different part in my post. My part was #89, the thing that looked like a PCV valve that is at the end of the hose from the valve cover to the start valve that Rowdie is showing. My valve got all gummed up and didn't seal up the back flow to the crankcase. I changed it because I was getting excess smoke out the exhaust.
Oops - different part in my post. My part was #89, the thing that looked like a PCV valve that is at the end of the hose from the valve cover to the start valve that Rowdie is showing. My valve got all gummed up and didn't seal up the back flow to the crankcase. I changed it because I was getting excess smoke out the exhaust.
On the valve cover side is a flat plate inside with a spring under it. In the intake side there is a , never mind I can't describe it. Any way the intake vacuum pulls and closes the valve. Here are a few pics. #1 valve, #2 Valve cover side, #3 the indescribable thing that pokes out when you push the plate in.
On the valve cover side is a flat plate inside with a spring under it. In the intake side there is a , never mind I can't describe it. Any way the intake vacuum pulls and closes the valve. Here are a few pics. #1 valve, #2 Valve cover side, #3 the indescribable thing that pokes out when you push the plate in.
Thanks for pics Rowdie! From what I have read:
Pic 2 the flat plate side - Shuts off breather if there is backflow caused by say a backfire through intake.
Pic 3 - The indescribable thing that pokes out - Valve stem that should seat and shut off flow when vacuum is high in intake.
Sounds like earlier MBs, like some domestic cars, had just a plate with a small (2mm) orifice in place of the valve with the indescribable thing...
Anyway - always something new to learn about these old cars!
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