200Tdi Wastegate

[varleym]

All

Had to take the exhaust manifold/turbo assembly off the engine 'cos the exhaust manifold gasket needed replacing. Got that job done fine but while I had the turbo off I found that the wastegate actuator mechanism was stuck solid. I disconnected the adjustable rod and the shaft that runs into the turbo housing and actually opens the wastegate is stuck rigid.

I'm trying to free it off with a combination of WD40 and small tool No 1 but in the meantime, a few questions:

1. How free should the actuation mechanism be when it's not connected to anything.?

2. Assuming I get it freed up is there anything I can do to stop it happening in the future, bearing in mind the engine's probably 20 years old and chances are no one's checked this part for years?

3. What are the implications of the wastegate not operating?

4. This could have been stuck for years - could it have caused any other damage to the turbo, etc?

Cheers

Mark

[Santa]

Hi the arm in to the turbo should be free to move , dependent if the arm is stuck open or closed , if open you will have low boost pressure as pressure will be going past the waste gate , if fully closed then possible problems with fuel mix as pump will be set up for a set pressure at full boost 9-11psi dependent on where engine from (discovery or ninety) also could cause problems with hoses, or arm could be stuck just open which could explain not having to may problems thus alowing some boost but not full amount.

[varleym]

Cheers Bob. The arm was stuck in the closed position but managed to free it off now. If it was stuck shut would that account for the clouds of black smoke when accelerating hard from low revs?

ALso, just noticed that the adjustable rod from the actuator to the arm I've been talking about is about a quarter of an inch too short to reach the pin on the end of the arm, as though the rod has been shortened. Should I adjust it so that it just reaches the pin 'cos that's maybe what's been causing the arm to stick shut (ie. a lot of spring tension on it when it's idle?).

Cheers

Mark

[Bo]

Hi Mark, the job of the actuator is to hold the wastegate closed until boost is reached at which point the boost behind the diaphram moves the actuator opening the gate. For it to hold it closed it needs some tension on it. The only way to set it correctly (or with a bit more boost) is to use a boost guage. You need 1 bar (14psi) in the inlet so the best way is to drill and tap for a boost pipe as close to the head as you can.
6mm short on your actuator rod sounds about right to me so you could just apply the "if it aint broke don't fix it approach".

[Santa]

Hi mark , yes should be short the arm is set at factory with correct pressure to open actuator then when set pressure removed and wastegate closed - to assembly on motor you can apply through a regulator air pressure . wind up from zero until actator moves cheak pressure when arm will engage , will normaly be a few psi short then increase to engines set pressure to make shore arm opens then remove air , you can tee into pipe to test boost pressue (manual states 11.3 psi for discovery 200TDI, 15psi for 300TDI)