Hopefully there are some smart cummins guys out there because this one has me stumped. 12 valve cummins has ran fine for quite a few years, I parked it for the winter and when I brought it out this spring and started driving it quickly developed the following problems. 1. a large oil leak coming from the push rod cover on the side of the block, gasket was pushed out. 2. excessive engine oil in the coolant. 3. engine crankcase filled with coolant. 4. an excessive amount of blowby out the dipstick tube and the breather. I checked the vacuum system for leaks and the turbo seals, both were ok. so I took the head off, and the head gasket did not appear to have any issues, I bought a new mahle head gasket and replaced it along with the pushrod cover gasket. At this point I'm thinking I took the head off for nothing and its an oiler cooler problem but I then pressure tested the radiator with 15 psi overnight and it held so the coolant wasn't getting into the oil that way. I put it all back together, torqued the head per ARP instructions and started driving it around. within a few miles the engine is up to the temp it normally runs at, about 160 degrees, I get on the throttle a bit up a hill and instantly the radiator boils over. I get it home and I can see the new head gasket is leaking coolant straight out the front of the engine from cylinder #1 and straight out the back of the engine from cylinder #6. I took the head back off last night, the gasket is clearly blown this time from the piston straight through to the outside. no penetration into the water passages that I can see though. I checked the head for flatness and I cant find anywhere where a 0.002" feeler guage will pass the straight edge. I have a new head gasket and oil cooler sitting at cummins for me to pickup today. I just don't want to put it all back together and have the gasket blow out again. Any idea what I'm missing? I didn't do a compression or leak down test but even if I had broken rings, that would explain the blowby, but not the head gasket failure? the engine does have 250K miles but the pistons look fine and the cylinder walls have no scoring that I can see. Before I put head gasket 3 into this truck, what else should I check?

 

Parked over the winter............. are you 100 percent positive you don't have a block that got nipped by Jack Frost?

Stranger things have happened........

 

I would have the head magnafluxed before doing anything else.

 

" excessive engine oil in the coolant. " any oil in the coolant is excessive!!!

 

I'd also check the block with a straight edge and a feeler gauge. Maybe the problem is there?

Magnafluxing the head is also good advice from Angry Johnny.
Pressure checking the radiator does not tell you anything about the oil/water heat exchanger in the block.
If you do not use ARP studs but stock Cummins bolts you will need to follow Cummins torque specs.
(And you need to check head bolt length before installation, a stretched bolt will "feel OK" while tightening, but will not clamp the gasket sufficiently)
ARP studs have a fine thread nut on top, Cummins bolts a course thread on the bottom. That may well be the reason for the Mahle gasket blowing so fast.

HTH

 

Definitely have head magnafluxed. Mine blew a head gasket, turned out my head had cracks between every intake and exhaust valve seats and at the injectors, my block deck was fine. I didn't have any coolant in oil, but did have some oil in coolant. New gasket, head and ARP 625 studs...no problems since.