Head crack question

[Can30Diesel]

Hi All,

I apologize in advance if this has been covered already. Here is the story.

I was changing my injectors out since I have never removed them since I rescued this truck from a farm a few years ago. The rear most passenger side injector bore had a bunch of carbon built up in it, so I cleaned it all out before installing the new injector. Once the carbon was gone I discovered what looks like a hairline crack or possibly 2 of them that seem to have filled with carbon. I have included a picture for reference.

I can only imagine I have been running around and pulling a trailer for the last 2 years with this crack in the head. I'm not loosing coolant or oil, and nothing seems to be mixing with anything in that area.

The truck has about 350,000K on it and it runs well. But regardless, this only has to fail once to be a pain in the .... so I'd prefer to replace the head.

Has anyone had a crack like this before and if so is it something to be concerned about?

Thanks for any help!

Here is the picture. Top is passenger side of engine, you can see the glow plug on the bottom as well for reference.

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[yARIC008]

It looks to not be cracked down in the seat which seems good... I've never seen a crack like this, i think its odd it formed there. Could water maybe have gotten down in the bore with the injector and then froze? Either way, doesnt seem good, but hell it may run just fine forever like that or blow up tomorrow. Hopefully someone knows more about it here...

 

[Wyreth]

The excess carbon build up in that hole makes me think the head should be replaced. I'd have to have the head off and look at it before I could begin to tell you how it could have happened, or what problems it is causing. However it's obviously doing something bad to cause that.

 

[Can30Diesel]

Well the truck did sit for a couple years on a farm, so I wouldn't be too surprised if some moisture got in at some point and froze.

I've done quite a bit to this truck already so I am no stranger to mechanical work, however, when dealing with a head, I want to be sure I am on the right track if I go to replace it.

So the part I am unsure about is what do I look for on the surface of the block in regards to warpage or other things that might need to be done before installing a new head.

I might have a line on a set of rebuilt heads which may or may not be used, but they are from an 86 6.9 whereas mine is an 85 and I am going to be looking into the history of them before I go ahead and buy them.

I am reasonably sure that other than possible structural changes (I read somewhere that the early 6.9's had some head cracking issues which were fixed later on) they should be the same head. If this is the case, would it be advisable to replace just the one head, or since I am in there anyhow just replace both of them? I'd be inclined to replace both just to retain the whole "matching set" thing. But then again I double my chances of having a head bolt snap inside the block.

Again, any thoughts, opinions or ideas are more than appreciated.

Thanks!

 

[hesutton]

I've not seen a crack like that in the injector bore. Mel has a cut cylinder head. One of the cuts goes right through the injector bore. I'll see if I can't find some photos of it (they are on here somewhere, I've seen them posted before) and see what's on the other side of those cracks.

Heath

 

[hesutton]

Ok I found the photo of the cut away head. As you can see below, there are no water jackets or oil passages near/at the injector bore. Not sure why it cracked, but if you aren't having problems and it isn't mixing fluids, I'd say keep a close eye on it, but leave it alone.

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Heath

 

[Can30Diesel]

Heath, that is the picture I was hoping to find. I didn't know where the coolant and oil passages were within the head and that is what I was worried about. I'll keep an eye on it and signs of mixing fluids for now and carry on.

If anyone else wants to chime in, please do, but with a pending camping trip I have been promising my family for a year now, I can feel the blood pressure going down.

Thanks again very much for the quick and useful help on here.