Valve stem guide cracked... What now?

[AlexTatar]

I have been changing the valve stem seals on my CLK 270 CDI today, after taking off all the valve stems seals I realised one of the guides have cracked! I've put one of the old stem seals back on to see if it would seal the gap which it does by a few millimetres, however I think under pressure it will start to let oil in. So what do I do now? - Alex

[ShiningWit]

Take the head off and have a new guide put in.

[Boosted LS1]

Yep, what he said. A local garage or car workshop/engineering repair place will just press it out and press in a new one.

[stevieturbo]

Have a new guide put in it, looks like head is already off anyway so no big deal.

[CarsOrBikes]

It won't let it in under 'pressure' as such, if it's an inlet vacuum will pull some through or if it's exhaust some may seep through with the engine off. If the seal is as tight refitting as the others it may work, but that will be considered a bodge. Some would even fix it too, but ultimately there is fatigue there to break the guide, or damage by someone, so pull the head, decoke it, and put a better engine together. I assume you know the glow plugs come out? If not try it now, because they break, and better to know now if facing head removal.