Tumble Flap Actuator Replacement
11-09-2015, 01:53 PM
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2008 CLK 550 Cabriolet
Tumble Flap Actuator Replacement
I did this task on Saturday, I have a few pictures and thoughts. (EDIT) The engine is an M272 in my '06 CLK 350. Symptoms were a very noticeable lack of power, especially from a stop. There was a code stored in memory for the actuator according to the MB dealer I had the car at.
The hardest part about this procedure is getting the engine wire harness out of the way. I will not go into much detail there but suffice to say it is a little difficult and requires time and patience to make sure you do not break anything. Once the harness is more or less out of the way, the injector fuel rail can be easily removed and the eight bolts that hold the intake can be removed. I did not completely remove the intake manifold as there are connectors below the MAF that I found difficult to get to & in any case I had enough room to work on the front of the manifold (where the actuator is) just standing it up in the 'valley'.
I must emphasize here that it is very important to be sure you do not let any debris fall into the intake ports of the cylinder heads. I stuffed paper towels into the ports and protected the mating surfaces with clean shop towels.
In the pictures below, shown is the front of the manifold with the broken actuator in place, next is a closeup of where the break occurs, next is a comparison of the broken and replacement aftermarket part and the last picture shows the aftermarket part installed.
Be sure you order new manifold gaskets with your new part. Mine were only @ $4.50 each, cheap insurance to make sure there are no vacuum leaks once back together. It was a little tricky to get the manifold back in place with the gaskets doing it the way I did it, but do take care to make sure the gaskets do not move or slip when you place the manifold back over the head ports. There are locating pins on the mating surface of the intake manifold for the gaskets, so this helps.
Again, I cannot emphasize enough the importance of keeping debris out of the intake ports.
Reassembly went fairly quickly. Once the engine started I had a problem with cylinders 4 and 6 misfiring badly as fuel was not getting to the injectors. I have had this problem in the past when I have had to pull the fuse for the fuel pump in order to depressurize the fuel system for other repairs I have made. #4 cleared up pretty quickly but #6 took a long time to get back into the game, really had me worried for a while there... I have a feeling air pockets form in the injector rail and the affected injectors starve for fuel until the pockets disburse. Just my theory, if anyone else has an answer to this problem please chime in.
In any case the operation was a success, full power restored.
The hardest part about this procedure is getting the engine wire harness out of the way. I will not go into much detail there but suffice to say it is a little difficult and requires time and patience to make sure you do not break anything. Once the harness is more or less out of the way, the injector fuel rail can be easily removed and the eight bolts that hold the intake can be removed. I did not completely remove the intake manifold as there are connectors below the MAF that I found difficult to get to & in any case I had enough room to work on the front of the manifold (where the actuator is) just standing it up in the 'valley'.
I must emphasize here that it is very important to be sure you do not let any debris fall into the intake ports of the cylinder heads. I stuffed paper towels into the ports and protected the mating surfaces with clean shop towels.
In the pictures below, shown is the front of the manifold with the broken actuator in place, next is a closeup of where the break occurs, next is a comparison of the broken and replacement aftermarket part and the last picture shows the aftermarket part installed.
Be sure you order new manifold gaskets with your new part. Mine were only @ $4.50 each, cheap insurance to make sure there are no vacuum leaks once back together. It was a little tricky to get the manifold back in place with the gaskets doing it the way I did it, but do take care to make sure the gaskets do not move or slip when you place the manifold back over the head ports. There are locating pins on the mating surface of the intake manifold for the gaskets, so this helps.
Again, I cannot emphasize enough the importance of keeping debris out of the intake ports.
Reassembly went fairly quickly. Once the engine started I had a problem with cylinders 4 and 6 misfiring badly as fuel was not getting to the injectors. I have had this problem in the past when I have had to pull the fuse for the fuel pump in order to depressurize the fuel system for other repairs I have made. #4 cleared up pretty quickly but #6 took a long time to get back into the game, really had me worried for a while there... I have a feeling air pockets form in the injector rail and the affected injectors starve for fuel until the pockets disburse. Just my theory, if anyone else has an answer to this problem please chime in.
In any case the operation was a success, full power restored.
Last edited by Bill51sdr; 11-09-2015 at 06:36 PM.
