Sprinter wastegate valve

Pegasus

New Member
Joined
Jun 24, 2013
Messages
3
Reaction score
0
Location
Ireland
Your Mercedes
Sprinter 312D 2000 2.9L
I have a Sprinter 312D - Hymer campervan. It seems to lack power when climbing hills, i.e. down to second gear on moderate hills. So I have been trying to find the cause.

I have discovered that the actuator for the wastegate valve on the turbo does not appear to move when the engine is revved (to about 3000rpm). I am not sure if it is meant to move or not when no load is on the engine. I also find that I cannot move the crank or control rod. I assume that it should move when the engine is running and it should be possible to move the crank manually when the engine is not running. I would be very grateful if someone could let me know:
If it is seized or is it meant to be like that?
Would this cause a lack of power?
Is it likely to be the actuator or the wastegate that is seized?
Are they easy to replace?

Many thanks.
 

NW_Merc

Banned
Joined
Apr 27, 2008
Messages
801
Reaction score
0
Location
Oop Norf
Your Mercedes
Mercedes W202
If the wastegate actuator isn't working (i.e moving as it should, pushing the connecting rod to the wastegate and opening the wastegate to bleed off boost) then your car would be boosting up like buggery, going very fast indeed with probably lots of engine pinking, and finally melting down / blowing up! (Though the last one is a little extreme)

The actuator's job is to bleed off boost as it builds, not to 'help' boost. It's a valve that is controlled by an electronic solenoid that allows engine vacuum into the unit to make it open up, and in turn open the turbo's wastegate to bleed off excessive boost, and hence not allow massive boost pressure to build up and destroy the engine.


If you are experiencing low / no boost, it could be that the wastegate or wastegate actuator are stuck in the 'open' positon.
 
OP
P

Pegasus

New Member
Joined
Jun 24, 2013
Messages
3
Reaction score
0
Location
Ireland
Your Mercedes
Sprinter 312D 2000 2.9L
  • Thread Starter
  • Thread starter
  • #3
Thanks for that. I guess that it is stuck partly open then. This would figure with the power only coming on in the top third of the engine rev range.
 

HiluxDriver

Active Member
Joined
Feb 16, 2010
Messages
26
Reaction score
0
I wasn't aware that the actuator on the turbo controls a waste gate. I thought the vacuum operated actuator controls the plates within the turbo which in turn alter the inclination of the driven blades and either increases or decreases boost pressure.

I know that on my old Peugeot camper the actuator operated a waste gate to prevent over boost. In my current Merc 316 turbo the actuator alters the blade inclination. Effectively the turbo action is very limited until vacuum calls for boost. If the blades are stuck in the minimum boost position then the call for power, which controls the vacuum to the turbo, cannot change the blade inclination. The result is poor performance.

Take a look at this video which shows how the bits inside move. As these plates are in a hostile exhaust environment they tend to block up.

http://www.youtube.com/watch?v=twwiV5YvHA0
 
OP
P

Pegasus

New Member
Joined
Jun 24, 2013
Messages
3
Reaction score
0
Location
Ireland
Your Mercedes
Sprinter 312D 2000 2.9L
  • Thread Starter
  • Thread starter
  • #5
I removed the wastegate valve actuator which runs pneumatically from the turbo boost side, and discovered that the linkage between valve and actuator was seized. I freed it and refitted the actuator. Goes like a rocket now compared to how it was. Many thanks for the help.
 

AIB understand your special Mercedes deserves a special insurance policy. We have a refreshing attitude to insuring high performance, modified, imported or classic and vintage cars and deal with the UK’s leading insurers. We offer discounts for length of ownership, where the vehicle is kept overnight and limiting the mileage and can also cater for those clients who need higher mileage and business use. To obtain a quotation please call the team on 02380 268351 or visit us atAIB Insurance
Top Bottom