where can I get a new overboost protection valve? - PeachParts Mercedes-Benz Forum

JB3 · #1 07-20-2013, 02:14 PM

cant find one on fastlane, where have people sourced these?

sixto · #2 07-20-2013, 03:34 PM

Pick-n-pull.

[edit] Oops, you specified new. Get the part number and shop Fastlane or the dealer.

Sixto
87 300D

sixto · #3 07-20-2013, 05:36 PM

Part number is 001-540-86-97 and depending on the phase of the moon it'll be listed as a transmission valve, intake manifold valve, EGR valve, air pump valve, etc.

Sixto
87 300D

Diesel911 · #4 07-20-2013, 07:41 PM

From the M Dealer Part Number 0015408697- MSRP $65.00 ; Online Price from the same place $48.75

JB3 · #5 07-20-2013, 08:06 PM

Awesome! Thanks guys!

winmutt · #6 07-21-2013, 11:32 AM

JY cost $3 and not made in China... Can fund them on just about any benz.

Graham · #7 07-21-2013, 03:59 PM

Would another option be to just bypass the valve? Hard to see what it is needed for. Seems like overkill. Having said that, I syill have mine, but did replace the connection which were leaking and a cause of major loss of power.

JamesDean · #8 07-21-2013, 05:20 PM

If the turbo pushes too much pressure the valve is opened and allows boost to push down on the ALDA cutting back fuel, which will in turn cut back boost..

AFAIK

Graham · #9 07-21-2013, 07:57 PM

Quote:

Originally Posted by JamesDean

If the turbo pushes too much pressure the valve is opened and allows boost to push down on the ALDA cutting back fuel, which will in turn cut back boost..

AFAIK

MB presumably put the overboost valve there as a secondary safety control to limit the boost pressure that the ALDA would see and therefore limit the amount of fuel that can be injected in the event that the wastegate (the primary boost control) failed closed (unlikely)

It is no big deal to have a valve properly connected and working. For it to work, there is a pressure sensor that must also be working.

There should be no problem to run with valve bypassed for short periods. I have heard that many owners run that way all the time!

winmutt · #10 07-21-2013, 08:15 PM

Without additional fuel the engine will not simply blow up when overboosted. It will however age prematurely. A much better solution is a boost gauge.

Diesel911 · #11 07-21-2013, 09:08 PM

Some where in one of the Threads is a proper description of what the Valve is there for.

Generally what I got from it is that it is to prevent a situation that can happen if you are heavily loaded down or towing something up Hill.
That would cause your Cylinder Pressure (I am speaking of the Pressure in the Cylinder when the Fuel is burning) to rise and at the same time increase the Boost Pressure that you do not need at that particular time because increased Boost would increase the Cylinder Pressure even more.

I also thought that the Valve did something to the Transmission?

winmutt · #12 07-21-2013, 11:25 PM

Quote:

Originally Posted by Diesel911

Some where in one of the Threads is a proper description of what the Valve is there for.

Generally what I got from it is that it is to prevent a situation that can happen if you are heavily loaded down or towing something up Hill.
That would cause your Cylinder Pressure (I am speaking of the Pressure in the Cylinder when the Fuel is burning) to rise and at the same time increase the Boost Pressure that you do not need at that particular time because increased Boost would increase the Cylinder Pressure even more.

I also thought that the Valve did something to the Transmission?

No.

Govert · #13 07-22-2013, 08:15 AM

Quote:

Originally Posted by Diesel911

Some where in one of the Threads is a proper description of what the Valve is there for.

Generally what I got from it is that it is to prevent a situation that can happen if you are heavily loaded down or towing something up Hill.
That would cause your Cylinder Pressure (I am speaking of the Pressure in the Cylinder when the Fuel is burning) to rise and at the same time increase the Boost Pressure that you do not need at that particular time because increased Boost would increase the Cylinder Pressure even more.

I also thought that the Valve did something to the Transmission?

Why would you not need the extra boost pressure and extra fuel when driving up a hill? The valve simply opens if the boost pressure is above 1.1 bar plusminus 0.15 bar. That can only occur if the wastegate isn't functioning properly. It opens under every driving condition, not only when you are driving up a hill.

The valve is an extra safety device: it is cheaper than an engine overhaul.

Quote:

Originally Posted by winmutt

No.

The early turbodiesels with 722.1 transmission had a transmission overload protection for driving slowly under full load.

winmutt · #14 07-22-2013, 02:53 PM

Quote:

Originally Posted by Govert

The early turbodiesels with 722.1 transmission had a transmission overload protection for driving slowly under full load.

Yes they did.

JB3 · #15 07-23-2013, 02:02 PM

Quote:

Originally Posted by winmutt

JY cost $3 and not made in China... Can fund them on just about any benz.

old benz's are getting pretty thin on the ground local junkyards. Only diesel ive been able to find was a 116 someone looks to have been in a fatal collision in, nothing in the engine compartment useful. the engine is smashed back into the passenger compartment, pretty horrible.

Anyway, im at the point where im starting to not find any spare vehicles for my various drivers in yards any more. This valve im going to have to buy new for what I need it for.