Can you identify this part for me?

[frankgant]

It's off a 2000 1.9 TDI manual tranny. It had two hoses connected to it like the hose you can see in the picture and a two wire harness. What is the part called and what does it do and effect if it's broken? Thanks for the help.

[DZLBUG]

That part is the changeover valve (N239), it is the solenoid that controls the vacuum signal to the anti-shudder valve (ASV) on the ALH engine. The ASV is the butterfly that is in front of the EGR.

If it is not functioning correctly, the ASV will not operate. The purpose of the ASV is to shut off the air coming into the engine to smooth out engine shutdown and eliminate the "dieseling" effect as the fuel is cutoff. It is also designed (this has been debated and is still debatable by some) to function as an anti-runaway valve. If your turbo were to let go, oil gets fed into the engine. The diesel engine will happily burn this oil as fuel, and it will rev up uncontrollably and either run until all the oil is gone and it seizes up...or it will consume more oil than it can burn and the engine will hydrolock and bend connecting rods in the process.

It is generally believed that the ASV will stay closed until the engine stops rotating. But I don't know that anyone has confirmed that this will happen, or that it wont happen. I know all this sounds alarming, but it is quite rare. The best thing to do if you ever experience uncontrolled revving of the engine (if manual) is to quickly get off to the side of the road, turn off the key, shift to 5th gear, jam on the brakes and dump the clutch. As long as your clutch isnt shot, this should kill the engine. If your car is an automatic, good luck and hope that the ASV will stop it when you shut off the key.

My advice is to have it in place and functioning correctly...but I'm a belt AND suspenders type guy...gotta cover your arse.

[frankgant]

Okay, now one other question. On the EGR valve there is a black plastic piece where one of the tubes from the solenoid connects. The little nipple on that black piece is broken off. Is there a way to fix this or can this entire black piece be replace without replacing the entire EGR valve. I really really appreciate the help.

Originally Posted by DZLBUG

That part is the changeover valve (N239), it is the solenoid that controls the vacuum signal to the anti-shudder valve (ASV) on the ALH engine. The ASV is the butterfly that is in front of the EGR.

If it is not functioning correctly, the ASV will not operate. The purpose of the ASV is to shut off the air coming into the engine to smooth out engine shutdown and eliminate the "dieseling" effect as the fuel is cutoff. It is also designed (this has been debated and is still debatable by some) to function as an anti-runaway valve. If your turbo were to let go, oil gets fed into the engine. The diesel engine will happily burn this oil as fuel, and it will rev up uncontrollably and either run until all the oil is gone and it seizes up...or it will consume more oil than it can burn and the engine will hydrolock and bend connecting rods in the process.

It is generally believed that the ASV will stay closed until the engine stops rotating. But I don't know that anyone has confirmed that this will happen, or that it wont happen. I know all this sounds alarming, but it is quite rare. The best thing to do if you ever experience uncontrolled revving of the engine (if manual) is to quickly get off to the side of the road, turn off the key, shift to 5th gear, jam on the brakes and dump the clutch. As long as your clutch isnt shot, this should kill the engine. If your car is an automatic, good luck and hope that the ASV will stop it when you shut off the key.

My advice is to have it in place and functioning correctly...but I'm a belt AND suspenders type guy...gotta cover your arse.

[DZLBUG]

That is the actuator for the ASV, do you still have the piece that broke off? Is it in the vacuum line?

If so, get it out of there. Take a straw off an aerosol spray can, put it through the piece that broke off and into the actuator. Epoxy or JB Weld it and then snip off the end of the straw when it is cured. The straw has enough of an opening in it to allow the actuator to function normally. If you don't have the piece, you may have to get a little more creative or buy a new part.

Unfortunately, this part is not available separately. It comes together as part of the entire EGR assembly. This would be very expensive when bought new from VW. Keep an eye out on TDIclub for used EGR valves if you think you need a new one.