Engine/Transmission (1994 - 1998) Cracked Head, What to do?!!!

[ctdf]

I have a 96 cummins 12 valve, I'm getting water in the oil, minor problem because the water is more steam and come out the breather pipe, nice creamy slime, I had the head off 6 months ago, leaking out in front of the thermostat housing and the shop said there was two cracks when he magnafluxed it, one was under the #3 exhaust spring and this appears to be where it is leaking. It wasn't leaking internally until after all the work was done, maybe the hot tank cleaned the crack out.

Any suggestion on how to fix this problem, block seal didn't work, I know another head would fix it, but has any tried welding a cracked head on one of these, or having one fixed, and is this a common thing or place to crack, any suggestion or info is helpful, or a good head cheap. Thanks for the help in advance, Chris

 

[Joseph Donnelly]

Cracks are common, not common to go all the way to water. Be sure your oil cooler behind the oil filter is not leaking, and try pressure testing the engine to try to find the problem (remove one injector at a time and check for coolant blowing into that cylinder.

 

[Jim Fulmer]

I've got a bone stock truck sitting in the shop right now that has the same issue, I did just like Joe says because it didn't make since, did the cooler pressure test... good, cracked under the valve cover about 2 inches long right to the exhaust valve on #4... ..... pressure test is a beautiful thing but not for the customer.



Jim

 

[The patriot]

Try e bay. I was going to get a spare about a week or two back.

It went for under $400. 00. It was "slightly used".

What do new ones cost? Is this a good price? It was a complete head.

Eric

 

[RHARVEY]

I seen one of those heads on Ebay about the same time you are talking. The only problem with something like that is ... unless the seller has taken the time and money to have the head magnaflux'd you make get the same problems.

And yes I know that most of the time when things like this happens... the funds are not there. But you can get a stage 1 head from Piers for about $1250. I do believe that it has been ported and some polish work. . and some other things. . This way you know what you are getting



Rick

 

[Jim Fulmer]

Piers's heads are band new ones, the one I got to replace the cracked one is stock but I had then O-ring it.



Jim

 

[Forrest]

ctdf ... ck my "Readers Rig" pictures. I had some cracks & PDR did the O-Ring job on a new head.

 

[JGheen]

Is head cracking related to one spinning the engine faster than 3000 rpm and/or with water or methanol or nitrous or even propane?? I would think all that extra stress on a stock head would cause it to crack. Just curious if I am in danger of cracking at all...

 

[RHARVEY]

I think its more related to heat... .



Rick

 

[JGheen]

Originally posted by RHARVEY

I think its more related to heat... .



Rick

Thanks, that was just about the reasoning that was going through my skull.

 

[Piers]

Heat doesn't bother the cyl. head... ... ... just tooooo much of it does. Keep the pre turbo temps to 1200 and under and you won't crack a head

 

[Jim Fulmer]

Keep the pre turbo temps to 1200



My gauge goes to 2000 for a reason!



Jim

 

[krs]

Jim, you're different.

 

[JGheen]

Originally posted by Piers

Heat doesn't bother the cyl. head... ... ... just tooooo much of it does. Keep the pre turbo temps to 1200 and under and you won't crack a head

Thank you for that confirmation from the professional.

 

[ctdf]

I pulled #3 valve cover and could see where the coolant has been leaking out and that valve cover had a lot worse buildup of the coolant and oil mixture in it. I didn't know you were to let off the power when it hit 1200 , I never did it pulling trailer, but thats what fun costs, I guess:{ . Thanks for the info, keep it coming. Chris

 

[Joseph Donnelly]

Around 1998 Cummins changed the valve spring seat area on the 12V head. The new heads have a generous radius from the seat to the valve guide. Old heads have a sharper radius and a big boss at the base of the valve guide area. Cummins said the reason for the change was to prevent cracking.

 

[Jim Fulmer]

I didn't know when they changed the head design but knew that they did it.



You can take it one step further and pressurize the coolant system with a tester while you watch the leak pour out if need be, the one I'm working on, I didn't see that till I was pulling the head off, yours and this one sound like the same truck almost.



Jim

 

[JGheen]

Could the 60# valve springs cause this cracking at all due to the increased seat pressure from the heavier springs... ... and maybe this and a combo of extreme EGTs??

 

[Jim Fulmer]

Could the 60# valve springs cause this cracking at all due to the increased seat pressure from the heavier springs



Nope, it's heat or a bad casting or both! Cool thing is I now have a New head from PDR with the correct surface and an O-ring to replace it.



Jim

 

[JohnE]

Originally posted by Piers

Heat doesn't bother the cyl. head... ... ... just tooooo much of it does. Keep the pre turbo temps to 1200 and under and you won't crack a head

Good to see you posting again.



Now heat. . Is this the pot calling the kettle black? The time I met you was freshly after you did a quick spin in the infamous blue truck at BD Dyno Days.



Don't say cracks.

Got oil in my coolant and hoping it is only a head gasket that let go. I get studs and o-rings now..... Cannot afford a new head.