Engine/Transmission (1994 - 1998) Head Gasket

[jw3500Ram]

My 12V is leaking coolant at the front corner of the head. Time to replace the head gasket. Does anybody have any advice on which gasket to use. Some say use a marine gasket, others say the new gaskets are marine gaskets?

The truck has 300K+ so I assume that rebuilding the head while it is off the truck is not a good idea? If you rebuild a head on a gasoline engine with high miles is almost certain to cause bottom end failure. Does this apply to the 12V Cummins as well?


Is there anything else I should do while the head is removed? The truck is basically stock; air filter, fuel plate etc. and makes about 32 lbs. of boost. I have 4500 LB springs for the injection pump and plan on adjusting fuel pump timing when re-installing head and fuel injectors next.


Any advice is appreciated.

 

[GrantP]

The truck has 300K+ so I assume that rebuilding the head while it is off the truck is not a good idea? If you rebuild a head on a gasoline engine with high miles is almost certain to cause bottom end failure. Does this apply to the 12V Cummins as well?

I don't see how you can correlate bottom end failure with a rebuilt head, other than the engine already had high mileage anyway. If you're going to go through the trouble of replacing the headgasket I would have the head redone while you're at it. 300k is no big deal for the bottom end of these engines.

 

[BigPapa]

^^^ I agree with this. Never heard that one before.

I just did a bit of research for a friend of mine on head gaskets. The consensus was the stock Cummins gasket on a moderately modded engine.

 

[Woodenhead]

Absolutely use a stock gasket from Cummins. If you're going to have the head rebuilt and decked then you should be able to stick with the stock thickness head gasket.
Hopefully you have a reputable shop nearby that can do a good job on the head, be sure it's magged for cracks before they bother doing any other work on it.

 

[DonFitzwater]

Fwiw- every 12 valve that I've replaced a head gasket on has ended up getting a new head due to cracking. They always seem to have a crack around the injector hole or between the valve seats. *This has just been my experience. None of my machine shops would rebuild them with cracks. New heads assembled are less than a grand to buy now a days.*

 

[Woodenhead]

Fwiw- every 12 valve that I've replaced a head gasket on has ended up getting a new head due to cracking. They always seem to have a crack around the injector hole or between the valve seats. *This has just been my experience. None of my machine shops would rebuild them with cracks. New heads assembled are less than a grand to buy now a days.*

I don't doubt that, it could go either way. When I pulled the head on my '96 back in 2007 it was fine, had it decked, o-ringed and rebuilt. I pulled it again in 2013, magged it again, still no cracks so it went into my '98 that had a crack on the exterior near one of the rear injectors. The '96 got a $450 Chinese head and sold to a friend, has been going strong for 3 years now.