Blown Head Gasket D6 9U

First with the head off check for any visible cracks as that happens after an overheating.Also prechambers can leak too so if your in doubt take it to a shop that knows what they,re doing. Also have the surface checked for flatness and also if the liner projection is ok but they need to be drawed down in place and held there while checking.Also going back cover the gasket with a coat of #2 Permatex as the long heads on them D318s had a habit of leaking out the side as I,ve seen it on dozens of them and the Permatex did the trick. Also install all new seals on the ferrules between the head and block.Torque down to the specs for the head and go half torque the first time around and then the final torque.Do the smaller nuts last for their torque.

I have rebuilt dozens of gasoline engines but I have never worked on a diesel. I have access to an engine machine shop. Should I surface the head?
On gas engines I do hard seats and cut them down on the Serdi. Is that done on this style head? Do you know how much the head weighs? Any ideas on what caused it to overheat in the first place? Thanks JP

Usually if fire has got under the head or coolant leaking it shows up as pitting and burning so yes the head should be shaved and also if it,s not flat end to end after checking with a long straight edge.If seats are bad in the head the head can be bored out and replaceable seats put in as they normally don,t hve seats in your engine.Sometimes just grinding the seats and narrow them up is all that,s required. I don,t have the weight of a head but probably is 150 lbs. or more (guessing). A few things can cause overheating, low coolant, bad prechamber gasket,or a low liner too letting compression in the coolant causing an air lock and a cracked head.Also a loose fan belt isn,t good either.

Check the radiator fins, they can be clogged and cause overheating. I would clean them out anyway just to be on the safe side. Charlie

Yes Charlie keeping the fins clean is one very important thing as I didn,t think of that.A fan blade on backwards too will cause it not to blow or suck but just spin and not drive the air whether it,s a suction or blower fan on backwards.

Since you know it is prone to overheating, while you have the head off, remove the block drain plug and perhaps the waterpump housing from the front of the block and make yourself a long probe for an air line or use a pressure washer wand that will fit down the block holes and wash as much crud as you can out of the block.

I would also be keeping the radiator in mind if you find lots of crud in the block. Removing the top tank and rodding the flues out will make a huge difference if it is like many of them with more than half of the flue clogged. I plumbed a garden hose into the bottom of the radiator and turned it on full blast so it pushes water up through the flues and you can see which are open and it also pushes out anything you dislodge as you work your rod up and down in the flue. We did flush the radiator with muriatic acid @ ~3% solution before we took off the top and it didn't do much good on the overheating, there was just too much crud in there. A lot of it was just laying on top of the flues keeping coolant from going down them, but by reversing the flow, you could see that the flues were mostly open a little bit.

If you deck the head (skim) check the hight of the dowls in the block, to make sure they dont cause any snags.

tctractors

Is there anyway to tell if the water pump is working corectly? It turns smoothe and doesn't make noise. Thanks for all the advice. JP

I say TC Old Boy, I feel the need for some translation into Colonial Speak here. Roughly translated TC means if you or anyone before you ground the deck of the block The dowels may be too high for the depth of dowel holes in the cylinder head. Thus the heads will not fully compress the gasket when torqued. Been there done that.
Wishing you a belated Merry Christmas TC, and a Happy New Year.
Later Bob