blow by at injectors on V3300 3.3 liter S220 2003

[tymwltl]

Has anyone had an issue with the injectors not seated down in the head of a V3300-T engine? The hold down plates that secure the injectors down into the head seem to not be holding the injectors down solid against the sealing washers. We are getting compression blow by up the side of three injectors under the valve cover. Has anyone had this issue and if so what did you do to make it right again? Is there an issue with the hold down clamps used to hold the injectors in the head ? [email protected]

 

[mmsllc]

I'd pull the injectors out & inspect them for missing crush / sealing washers. It kind of sounds like they might be missing all together. Or, maybe they are the wrong length / type injectors from a previous repair. I'd pull them out to inspect them for proper fit & type. It just sounds a little sketchy to me.

 

[Tazza]

I'd pull the injectors out & inspect them for missing crush / sealing washers. It kind of sounds like they might be missing all together. Or, maybe they are the wrong length / type injectors from a previous repair. I'd pull them out to inspect them for proper fit & type. It just sounds a little sketchy to me.

There is no reason why they shouldn't be sealing. If they were loose at one point, the gas escaping could have cut a groove in the copper washer. I had a 743 that had this issue, they were not tight and cut the copper washers up.
One thing to check is that the seat is nice and clean. If it has been by-passing for a while, there could be carbon build up on the seat of the head. A pick or even a screw driver and compressed air will blow it out of the way.

 

[mmsllc]

There is no reason why they shouldn't be sealing. If they were loose at one point, the gas escaping could have cut a groove in the copper washer. I had a 743 that had this issue, they were not tight and cut the copper washers up.
One thing to check is that the seat is nice and clean. If it has been by-passing for a while, there could be carbon build up on the seat of the head. A pick or even a screw driver and compressed air will blow it out of the way.

Exactly, carbon build up could cause a false sense of being tightened. Just imagine that they wiggled / got loose before, then someone ran into this similar issue, then removed the injectors & replaced the copper seals, then put the injectors back in the engine without ever cleaning out the carbon. Eventually, the carbon could have burned off & that left the injectors loose once again. Every time injectors are removed, there bore should be cleaned with a wire brush to eliminate this possibility of a future problem. Granted, very few of us clean the bores every time. It can lead to problems, but what can you do??