This started with a little blue smoke and a slight miss at idle. So I start a diggin and this is were I'm at, head still on (waiting for my buddy 'tiny' to show up and help) and oil all in/over the exhaust manifold on cylinder number 5. I'm ready to pull the head but worried as to what I'll find, this could be bad... Could a bad head gasket pass oil through to the exhaust? What could I be looking at here? Thanks fella's.

 

maybe a valve guide?

 

It doesn't usually happen that way with a HG, but anything's possible.

Before you yank the head, pull the #5 rocker box and have a look. If you put the piston at TDC you can pull the valvesprings and let the valves sit on the pistons while you check sideplay on the valves and replace the seals if you find a bad one.

 

If it is lots of oil, I would think it might be in the rings. Since there is basically no vaccum on a diesel(usually ), I would think the valve guide would have to be really bad to cause a problem like this.

I don't think the HG could pass oil directly to the exhaust. It might be leaking oil into the cylinder though.

Let us know what you find.

 

I'm a slow typist.

 

OK, the head is off and it's my lucky day! It's the head gasket. I'm going out to take a couple pictures, for you all to see, I've never seen one go like this. The metal sealing ring broke away and was letting enough oil in the cylinder to smoke like crazy. I was really happy to see the pistons and bores looking so good at 290,000 miles, cross hatch and all. Thanks for the tips BTW! I did pull the rocker on #5, pulled the springs, and checked play in the valves. Both intake and exhaust valves were in great shape. I replaced the head gasket with a cummins part about 20k ago, had myself convinced it was in the bottom end, should have known better, the old truck has done me nothing but good for the last 14 years!

 

That's the best news you could have hoped for.

 

Now I'm rereading the post, I'm doubting valve guide based on your miss you had. That is pointing towards rings if you were loosing compression/ getting oil.... or a hole in the piston??

Are you 100% it's engine oil? Wondering if your injector is shot with no or little pop pressure. maybe just spraying with no atomization... there for a miss and the diesel is in the exhaust manifold?

 

... now I'm the slow typer

 

I started with the fuel system, looking for an answer but no luck there. Moved on to the turbo and found oil in the exhaust pipe, pulled the turbo found it in the manifold... I have a photo of the gasket in my gallery of what I found. Very good news indeed! Thanks guys.

 

Make sure that head and block are flat! And the bolts/studs are holding down good. Are you letting the truck warm up a little before driving it hard?

 

Was that the original head gasket? Probably got worn thin over the years from all the slight movement. Saw the same thing happen on my mom's Pontiac minivan, only it was coolant instead of oil, but the same thing happened to the head gasket.

 

It was a replacement gasket from about 20k ago, I replaced it then because of a water leak up by the thermostat, the original head gasket made it to 170k. I had the head reconditioned then, although it didn’t need much because it was in such good shape. I always let it warm up before heading out, and never any real power till I have good water temp. I've had a little smoke for awhile, I wonder if it was a defect in that replacement gasket. When it finally let go it made a little blue smoke and had a slight miss at idle, when you gave it any throttle it would really smoke and shake the truck as would take that cylinder down.

JD730, thanks for getting that picture up.