Coolant loss

[Waterloo]

(03-20-2021 )03maxpower Wrote:  

(03-20-2021 )tree98 Wrote:  BEFORE YOU PULL THE HEAD!!!!!......drop the pan and pressurize the cooling system to 20 psi, let it sit overnight and then check for coolant running down between a liner and the block. You might have to slowly bar the engine over, look closely it can be easily missed.

I would bet a lot of money you dropped a liner, especially if cummins just worked on it not long ago. You really shouldn't let those guys anywhere near your engine.

I’m a little ignorant to this so I have to ask. How does that happen? Could it have been prevented and how? I know what’s done is done, but if that’s it I don’t want something like that to happen again. Thank you

The liner(s) break loose internally from the ledge they sit upon due to the increase in lateral thrust, which is caused by lugging the motor under loaded conditions. The rod and pistons bust them loose, more like beats them loose. The liners simply drop in from the top of the motor and sit on the slimmest, very narrow ledge, and the weight of the head keep them intact. Hit them with side pressures often enough, that lateral thrust, and they break loose from that ledge and take out the head gasket and eventually the head.

ISX heads and gaskets do not fail on their own, other than through abuse or age. Under normal conditions an ISX head and gasket can go darn near two million miles without issue with proper care.

This pressure test of the cooling system that Tree mentioned is the only sure way to find if a liner has broken loose and has taken out the gasket. And it does not take much, just a few thousandths of an inch will do it.

Pressure up the motor to 20psi via the cooling system, drain the oil and drops the pan. Let sit overnight, if it falls more than a few PSI you have other issues, a loose clamp, etc, so make sure everything is tight before you pressurize. Let sit, in morning you will need to be able to bar over the motor. You will need someone barring the motor and someone under the motor with a good strong flashlight. you will be looking for coolant droplets on the cylinder walls. Normally it is cylinder five or six. Mine was five. Also, make sure you are in a quiet space when barring the motor, as you will hear the leak, a swishing/woosh/gurgle sound as the crankshaft is turned, you will hear it up at the head through the liner opening. Odds are you will hear the gurgle/swoosh sound before you will see the coolant. It sounds like lightly blowing air through a straw into a glass of water.

If a head gasket fails, there is a 99.9999% chance a liner has broken loose and the motor will need to be in framed. And only use a new OEM Cummins head, they are not refurbishable, no matter what Cummins says, one time use and send to the scrap yard.

The fix for your issue is to disassemble the motor, pull the liners and cut the ledge for the liners, then add shims to get the liner height up to .0014 of an inch protrusion. That is your only fix.

The problem is, very few shops ever follow the Cummins manual and machine the block and add the required shims, much less do they even measure liner heights. It is very rare that even a real Cummins shop will follow the manual and do this step. Even some Cummins factory re-manufactured motors have this step skipped, they are junk the day they are installed. They throw the liners in, and slap on the new gasket and head and call it good. The Cummins manual is very clear on the step requiring the block be machined and shimmed to accept the new liners. There is no plan B. The norm is to skip this crucial step, as the tools required to do this are not cheap, and it requires a bit of skill to do this step correctly. Most shops totally ignore this step, even if they tell you they do not. They have no issue lying to you, they got your money, and odds are the liner will hold until after the warranty expires. Then you can go suck an egg.

I was a victim of this myself, cost me $38,000 the first go around. Rawze saved my bacon by inviting me to his house to fix, we in framed the motor in his driveway. That first in frame, it lasted 70,000 miles, as that is about the time my head gasket failed, and it destroyed my new head.

Two in frames in two years, do not be that guy. Unless you have deep pockets and or a masochistic streak in you.