Coolant Leak

[BubbaJo]

Hey guys,

Today, I noticed that my engine temp shot up like a rocket on my way back from a plant to my main office.

I stopped and noticed there was very minimal coolant in my overflow tank.

I took off from work and stopped and got some coolant.

Poured about a 1/2 gallon into my overflow tank, so it was between the min & max lines. I wasn't 100% level but figured it would be golden.

Drove home, temps were good the entire time.

I got home on a more level surface, and my coolant level was back to where it was before I poured the coolant in!

I only drove about an hour (45 miles).

There is no white smoke, no coolant smells, and no coolant in the oil (no foam on the dipstick or the oil cap).

I topped off the overflow tank in the driveway and let the truck idle for a couple of minutes while i brought my daughter inside. It never moved.

There are no signs the head gasket is leaking either.

The top coolant tube is nice and squishy; no coolant leaks around the head either.

Where else should I check?

2012 with no performance mods and bone stock drivetrain.

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[BubbaJo]

Right now I have a clean piece of cardboard under the truck while it's idling to check for leaks and nothing so far after 5 minutes of idling.

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[BubbaJo]

The coolant level in the overflow tank remained the same, no drops of anything, not even oil, appeared on the cardboard.

Held down the accelerator down at 1500 rpms for a brief period of time and let it off.

Did it twice.

Still nothing different.

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[Aboshan]

When we see this on the big Cummins, the EGR cooler leaks internally into the exhaust.

If you have all the emissions intact, it will not show any smoke or steam out the exhaust, but it will plug up your DPF much faster than normal.

That also brings the possibility of coolant entering the cylinder and hydro locking the engine.

The EGR is slightly different on the bigger Cummins as it sits lower than the ones on the 6.7L and isn't as prone to hydro-locking.

To be clear, I have not heard of a 6.7L hydro locking, but the way the EGR cooler mounts above the exhaust manifold, the possibility is there.

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[BubbaJo]

I did check the exhaust itself and it's dry.

How would I check to make sure this isn't happening?

Is there any signs that would clue me in on this happening?

Different sounds? idles differently?

Anything other than pulling the EGR itself?

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[TexNeck]

Following- 2012 with single radiator correct?

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[BubbaJo]

To my knowledge yes.

I forgot to add.

I've never seen any puddles or anything under my truck either.

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[Murph]

To my knowledge yes.

I forgot to add.

I've never seen any puddles or anything under my truck either.

I'd be pulling the egr and much like a radiator, pressure test that pig. especially after the better part a gallon added. Did you burp the cooling system after the two adds of coolant? Maybe just low? Have you flushed or performed any maintenance since you've owned the truck on the coolant system? Might as well ops check the T stat as well if you pull the EGR. Just some ideas as I read this and wish you luck Sir.

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[Murph]

To my knowledge yes.

I forgot to add.

I've never seen any puddles or anything under my truck either.

When was the last time the EGR and valve was cleaned?

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[Aboshan]

The only way we could tell was to pull the EGR or check the DPF filter which are removable on the big Cummins unlike the 6.7's.

There was no noticeable difference in the way the truck ran.

The telltale sign was losing coolant and no external signs we would replace the EGR.

Both of my 2016 ISX12 Cummins have had the EGR replaced that being over a year ago.

Being a 2012 I would certainly be on my short list to check.

I suppose if you could get the bolts loose on the downpipe to the DPF you could shine a light in there or maybe feed a small camera in through one of the sensor ports to see if the DPF filter is the same color as the coolant.

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