WJ grand Cherokee 2.7 CRD

[Geoffjake?]

I checked around the injectors for black death as the injector seals on this model are prone to leaking ,I noticed one of the injector clamp bolts was bigger than the rest ,I suppose the threads have been stripped out ,so an over size thread was tapped into the head ,the bolts are stretch type and have to be replace when removed ,my question is should I replace this bolt when I remove the injector ,and what amount of torque should I tighten it up to ,thanks for any advice ,by the way I live in England but I think Austraila is a wonderful country

[Deezelweazel]

This might be the wrong section to find advice, maybe some of the admins is moving it into the WJ section.

My advice:
Since strech bolts are used for a reason it makes sense to use them if possible. Spare bolts can be purchased dirt cheap at your local UK Mercedes parts dealer.
The oversize bolt can be brought back to the original size by using so called heli coil inserts. These coils, made of stainless stell are inserted with the appropriate tool into the hole. The heli coils are coming as a set with all required tools. They are used to reinforce or to get reliable threads in such soft materials like aluminum.

Be careful with bigger bolts since the cylinder head cover isn‘t that thick, it does like to crack. If you don‘t have the experience ask a shop to perform this task. But the result is worth it- you will get a reliable thread as good as new.

[Deezelweazel]

Thighten it with 7Nm, then a single 90 degree. Older manuals do demand two times 90 degree- thats to much force and was changed to a single 90degree turn.

Before inserting the new bolt- clean the thread by using an old bolt.
Cut a line into the bolt with grinder, use it as a thread cleaner. Take your time to get a pretty clean thread!