Does anybody know what size star bit it takes to remove the 2 bolts that hold it to injection pump, I wanted to buy a good quaility bit. Also can the plastic on these shutoff valves crack over time and leak or is it usually the o ring that attaches it to the injection pump. Thanks for any help

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84 300 Turbo / 320,000
96 E300 D / 55,000

Sometimes it's not that easy to tell just where the leak is coming from; however, I beleive I've had the valves themselves leak on each of my three OM606 motors ... all at around 200,000 miles. The leaks in my estimation seemed to come out of the electrical connection but everything was wet so it could have been a crack. When I replaced the valves on each car I also replaced all the plastic lines and o-rings which has gotten me at least 50,000 miles without any fuel leaks on each car. I'm not sure of the exact tool size to remove the bolts .... but it makes sense to get a good set because you can find those fasteners in odd locations and differening sizes around the vehicle. Good Luck.

Yup, buy yourself a torx bit set. Its a T-30.

A leaky SOV is typically the SOV oring or a fuel line oring attaching to it. When they fail, they usually get "sticky" where the valve fails to close fully when the key is turned off and the engine runs on a few moments before shutting down. A bad oring can also cause the same delayed shutdown.

Spray the bolt heads clean before you insert your torx bit. I think the torque is no more than 20nm.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

I've also had SOV's that leaked out of the electrical connection (on our '98 and '99). Never got around to cutting a failed one open but my guess is there's an O-ring or other seal inside that fails and lets fuel leak out past the electrical pins - and lets air leak back in when the engine's off. The O-ring between SOV and IP is the most likely culprit, but the valves can fail internally.

Now, Im working on a "bungied" up T-30. Wonder if they used some Loctite on it? Its mate showed no signs of thread sealer. It wont break with any normal Tq.

I had a similar problem with the screws holding in the shut-off valve on one of my cars (other two no problems). Since I was replacing the valve I just ended up drilling off the head of the screw, taking off the valve and then turning out the threaded stud that was sticking out of the injection pump. I suspect you could do the same but be careful not to drill through the valve if you want to save it. I ended up ordering new screws from the dealer for that car.

Took the manifold off and removed the shut-off valve had a hairline crack in it, about a year before I replaced every plastic line on the system and replaced all DV seals on injection pump, the only thing I did not replace was the shut-off valve, JUST MY LUCK!!!!!

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84 300 Turbo / 320,000
96 E300 D / 55,000

Well at least now with everything new you should get some 50,000+ miles without any leaking problems. The only thing left is the delivery valve seals inside the pump that can leak ..... that's a job that is a little more involved to address but it to is doable. I've also replaced those seals on all three of my cars. The dealer won't sell the seals for a 1996 so you have to tell them you have an 1987 300D to get the right seals and crush washers .... but that is another story. Personally I think a lot of the leaking problems are probably related to the reduction in sulfer content in diesel fuel in recent years. I read a techinical report on the matter from Chevron a few years ago that predicted that many diesel vehciles with older rubber seals exposed to high sulfer content fuel would eventually develop leaks with the new lower sulfer fuel due to shrinking rubber. But now that you have all the seals replaced you shouldn't have any more problems for a long while.