Advice needed. Rebuilt engine, coolant leak.

[jimbo486]

I'm in need of some help with this.

Some of you have probably seen my engine build thread. Yesterday, in preparation for the first start-up and cam break-in, I filled the cooling system with straight water to save good coolant and to test for leaks. Sure enough, I had one. Unfortunately, it was coming out at the rear. The engine hadn't even been turned over yet. This was simply from the head pressure of the water within the system. As soon as I found it, I drained all of the water in case there were any internal leaks that could fill the crankcase or cylinders.

Today, I pressurized the system without water to 15psi. Of course, I didn't hold. Pressure dropped to 10psi after about 45 minutes. With the help of some soap and water, I found more than one leak. Seems like be on the exhaust side, mostly around the rear 3 cylinders and one spot out of the rear (I think). I took the best pictures I could with my phone using a mirror and flashlight.

Is this somewhat common after a fresh rebuild or with an o-ringed head in general? The head was machined prior to the o-ring grooves being cut. The machine shop that built the shortblock assured me that the deck was good. If I have to pull the head and find that the deck is out of spec, the shop will certainly get an earful!

I'm wondering about a retorque. Maybe the studs have relaxed some in the time they've been sitting after their final torque? Brandon (12vriviera) suggested a retorque followed by running the engine without water for the cam break-in, another retorque and then fill with water to check for leaks again.

Please help! I hope the fix is something simple. Thanks in advance for any information you can provide!

 

[Mooner1]

Damn dude, that sucks. That seems to be sound advice from 12vriviera though with where you are at with the build and all. I've been following along and look forward to see/hearing the new motor rip man.

 

[jasonc]

What protrusion is the o-ring wire on the head and what torgue did you get on the studs. With stock bolts I can usually get about 140 by going slow in 5lb increments and it needs that to crush into the fire ring to pull the head down enough against the block to seal the water ports. Before you do anything re torque the bolts again and if the get spongy after 135 go in 5lb increments with a long break in between to let the bolts cool down. If everything was done correct it will pull the head down and seal and be fine.

 

[jasonc]

After a couple of heat cycles re torque again, high o-ring protrusion holds the cyl pressure good but you have to get alot of torque to get the head sealed off. If you have 625 studs you should be able to go right to 150, I've got 145 out of the cheaper studs by being carefull and slow. Good luck!!

 

[Marq92]

How many re-torques have you done?

 

[jimbo486]

ARP 625s. No retorques just yet. After the head was set down, they were torqued following Cummins' 3 step sequence up to 89ft lbs., then incrementally up to 150ft lbs.

It's been a while since I measured ring protrusion but it's .010-.012".

 

[Marq92]

With o-rings, re-torques are needed. I would do 3-5. Break each one loose in sequence and bring back up to 150.

 

[9724VF350]

What brand gasket?

 

[jimbo486]

Thanks, Mike. I knew re-torques are needed but I only figured it was to be done a few times after some heat cycles. Sounds necessary even before the first heat cycle.

Victor Reinz gasket from the Mahle rebuild kit.

 

[fatty]

I'd say you must have some other problem. I don't see how unpressurized water could leak through a gasket clamped at 150 ft lbs. Are you absolutely, 100% positive the head is seated correctly?

 

[9724VF350]

Victor Reinz gasket from the Mahle rebuild kit.

Boom. Victor gaskets require .002-.003 less wire protrusion than a OEM Cummins gasket due to a more difficult to crush sealing area.

If you start it, it will probably also leak oil like a stuck hog.

Stick a OEM gasket in it and call it good.

 

[jimbo486]

Boom. Victor gaskets require .002-.003 less wire protrusion than a OEM Cummins gasket due to a more difficult to crush sealing area.

If you start it, it will probably also leak oil like a stuck hog.

Stick a OEM gasket in it and call it good.

What I've gathered is that VR has been making gaskets for Cummins for sometime now and more recently, Mahle.

 

[9724VF350]

What I've gathered is that VR has been making gaskets for Cummins for sometime now and more recently, Mahle.

Clevite/victor/Mahle is all the same company.

The Oring info is from a freind and customer of mine that has oringed over 200 heads in the last 4 years. He buys 90% of his gaskets from me, either oem or victor. I sell both.

 

[jimbo486]

What differences have been noted? It's common knowledge that all of them use a stainless steel fire ring. I can't imagine the gasket thickness varying at all. A standard is around .060".

 

[jimbo486]

Well, after a cold retorque, running the engine without water to about 180°, shutting down and a hot retorque, I still saw some bubbles from the same spots.

However, I figured the ideal test would be to fill the system again with water and pressurize it.

I saw no leaks from anywhere with just the head pressure within. So I pressurized the system to 16psi and so far I haven't seen a drop from anywhere. So far pressure has been holding steady for about 30 minutes and still no evidence of a leak anywhere. I'm gonna let it sit for about another hour just to be sure. Although, I'd like to think if it were going to leak, it would've by now.

So far, so good!