Has anyone ever had a head bolt "break" for no reason.
The bolt is sucking air and leaking but for no reason that we can tell?
This is on a 1986 F-350 with a 6.9

 

Not me. Which bolt is it (just curious)?

It must be possible, that's why they upped them to 1/2 inch for the 7.3s

 

I havnt seen it yet a employee of mine has it and is bringing it back in the morning.

 

So nobody has any ideas why this would happen?

 

If the engine heads were removed before and new bolts were not installed, the old ones have stretched, when they are re installed (bad thing) they will occasionally bottom out in the block 1) if the bolt holes are not bottom tapped to remove all debris. 2) if they are stretched too long they bottom out and get twisted and can snap later. The 6.9 is bad for head gaskets leaking.

There is also one other possibility if it is a rear head bolt, if there was oil entering the intake via the CDR valve.........

CDR info..........
All 6.9L and 7.3L diesel engines are equipped with a CDR (Crankcase Depression Regulator) valve. Even the new 7.3L Power Stroke is also equipped with the same valve. The CDR valve is one of the leading causes of head gasket failure in these engines. The CDR valve is responsible for controlling the pressure/vacuum in the engine crankcase, and seperating the oil mist from the air and returning the oil to the crankcase. The CDR valve should be serviced every second oil change or when signs listed below are seen.

When the CDR valve is not properly serviced, engine oil enters the air intake and is drawn into the engine. The diesel engine will burn this oil as fuel, however, it is heavier and thicker than diesel fuel and, having greater BTU output, causes excessive heat in the cylinder. Due to the intake manifold design, most of the oil will migrate to #7 and #8 cylinders; the last two cylinders in the rear by the firewall. The increased temperature here will cause the cylinder head to lift off the gasket and allow water or oil to leak out the back of the cylinder head where it meets the block.

To check your CDR valve, remove the air cleaner hold down bolt and inspect it. If the bolt is covered with engine oil mist, it's time to service your CDR valve!

To service the CDR wash with a solvent, allow to dry, do not use compressed air to dry. There is a small hole in the CDR back cover, ensure it is clean and open. If black chunks of rubber are visible in the intake, on the screen then the rubber membrane has disintegrated, replace the CDR.

 

Thank you thats what i was looking for.
Nobody has touched the head bolts in the last 6 years that I know of so I knew there had to be another reason.
Things like bolts dont usually just break.

 

Ok is the CRD a silver can about the same diamiater as a soup can only shorter?
Two bolts holding it on.
Just remove those bolts and it come off?
Thanks.

 

I'm kind of curious about this whole theory. I've never seen a dry CDR valve, and there is always oil laying around in the intakes of these things when you pull the air cleaners. If this was the reason for a broken head bolt, I'd think this would be a widespread problem. I do think they can get enough oil in them to increase consumption, but the head bolt? It was probably streched at the last head gasket job and just finally had enough.