2018 Head Gasket - 2018 Crew Cab 6.7L Cummins

[Drake1]

Good evening; I purchased my truck brand new in March of 2018.

2018 Crew Cab 6.7L Cummins.

In March/April of 2020, I did a full delete with DRD MM3, 30hp tune, full 5” exhaust with EGR delete.

The truck has been great; recently, I’ve been smelling coolant after shutting off the truck and walking by the front end, I couldn’t find anything leaking, and the coolant reservoir seems to stay level.

The truck has only 33k miles.

Today I got home from about a 40-mile drive, not towing anything, and wasn’t hard on the truck; again smelled coolant, so I popped the hood to look again.

The upper rad hose was hard as it usually is after driving for a while, I opened the coolant tank, and it immediately overflowed coolant out of the tank?

This is my first Cummins, so I’m looking for some input?

Is this a bad head gasket already?

Is it normal?

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[steadly2004]

Did you open it up while still hot?

If it was hot, then overflowing would be expected, I believe, but I’m 100% sure.

I would be searching for any evidence of coolant leaking and burning/evaporating off.

If you are getting a smell.

However, if the level never changes, I wouldn’t worry too much about it.

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[AK Bob]

Agreed, I would expect the coolant tank to overflow when the cap is removed if the engine was still hot.

You could have up to 20psi of system pressure, and it will take the path of least resistance.


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit, and 50 Gallon auxiliary fuel tank.

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[Krazy8twofour]

If you did an EGR delete- you could’ve spilled coolant and have residual coolant burning off.

Or, I didn’t get the connections tight and are now leaking under pressure.

It sounds elementary, but just throwing out options.

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[Bpbertolacini]

I would check the notorious o ring that leaks on the coolant riser pipe from the delete fitting to the head coolant nipple.

I had that leak on mine on the bottom, and it took me a minute to find since it would drip down on the air intake by the turbo.

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[Drake1]

Yes, the engine was still hot; I just shut it off 30 seconds before opening the overflow bottle.

Hopefully, that’s all it is!

Thank you for the replies!

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[KJC]

Check water pump as well, and I've had water pumps that only lasted 30,000 miles.

If the water pump is leaking, you will see it on the front of the oil pan.

If you can't find any leaks anywhere and the coolant level stays constant, I wouldn't lose much sleep over it.

My wife's Chrysler 300 always smells like coolant after being driven for a while but never loses any coolant and has no obvious leaks.

The tiniest bit of coolant weeping out somewhere hot is all it takes to smell it.

Kyle

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[Cowwboyy]

It is a tough bet

Do you have it studded?

If you’ve put a couple of gallons in the reservoir over time and you’re getting the pressure build-up, and it’s still blowing out, it's a good indicator for sure the head gasket.

From having earlier 6.7’s and having studs put on them, the guys I’ve worked with swear up and down not to exceed 1150-1200 degrees for EGTs.

If you put that tune on and lug the shi* out of it, you’d be surprised how hot the EGTs can get.

I could be wrong, but suitable for thought?

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[Cole60]

Mine did the same thing.

I don't recommend ever opening the coolant tank while the truck is hot.

It will overflow and sometimes shoot coolant out everywhere and possibly burn you, but for the slight smell, I wouldn't worry about it as said above; if it's staying cool and level is good, then probably some burn-off.

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[Murph]

Good evening; I purchased my truck brand new in March of 2018.

2018 Crew Cab 6.7L Cummins.

In March/April of 2020, I did a full delete with DRD mm3, 30hp tune, full 5” exhaust with EGR delete.

The truck has been great; recently, I’ve been smelling coolant after shutting off the truck and walking by the front end, I couldn’t find anything leaking, and the coolant reservoir seems to stay level.

The truck has only 33k miles.

Today I got home from about a 40-mile drive, not towing anything, and wasn’t hard on the truck; again smelled coolant, so I popped the hood to look again.

The upper rad hose was hard as it usually is after driving for a while, I opened the coolant tank, and it immediately overflowed coolant out of the tank?

This is my first Cummins, so I’m looking for some input? Is this a bad head gasket already?

Is it normal?

If you chose to delete and leave in place the EGR, this could be a bit more difficult to detect.

As with some of the other members having eluded to, and my own personal experience that matches yours, I found the aft EGR coolant supply line leaking from the engine.

I finally found the leak and evidence of cooking off and no-drip (EGR removal and cleaning allowed a perfect visual).

The leak streamed to the back of the engine (under hood airflow) and left a visible jellied trail that tampered off at the back of the exhaust manifold.

Good luck!

Also, how about the turbo cooling lines and their path as well?

Great cooking temps there as well, LOL!

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