Antifreeze gone 2019 Cummins 605hp

[Jeff753]

No antifreeze in reservoir tank
Turns out it's 6 Gallons low
Test to 15psi no leak down.
What tests should cummins run and is this a possible huge repair?

[SafariBen]

Yes, this is a possible huge repair bill. Could be a huge bill just for diagnostics and not find anything.



What's the rest of the story? was it sitting for 6 months? or were you on the road everyday for weeks? how did you notice it was low, and when would it have been checked last?

[wolfe10]

After filling, do you see a leak under the coach?


Have you looked at the OIL? Is it clear black oil or "chocolate milkshake" colored?


Could it be expensive-- sure. Could it be a broken hose clamp-- sure.


Remember, coolant runs from engine to cash heater core and if motor-aid water heater to it as well. Check these as well.



Please update us on what you find.

[Jeff753]

Originally Posted by SafariBen

Yes, this is a possible huge repair bill. Could be a huge bill just for diagnostics and not find anything.



What's the rest of the story? was it sitting for 6 months? or were you on the road everyday for weeks? how did you notice it was low, and when would it have been checked last?

We are looking at buying this 2019 Cummins 605hp RV and have seen the service record for a standard service in 23. In that write up Cummins states "no coolant in reservoir" "Added 7 Gallons to bring up to level"
"Pressure tested coolant system to 15PSI Could not find a leak at this time."

[d23haynes57]

If it always leaks down the same amount I would be looking for a defect in the radiator and/or a bad pressure cap. Front heater can also cause a same level drop. Look for any signs of the orange trail. Another possibility is combustion gasses getting into the cooling system and blowing the coolant out.

[Old Scout]

Depending on your rig, the avg 605 coolant system will hold 20 plus gal of anti-freeze--so 7 gal is a lot but not all of it. Three options: 1- it's leaking externally--should see puddles; 2- it's leaking internally--would see it in the oil--bottom of oil pan--"sample" tap plug, or 3- it's burning it, white smoke??? Whichever, funny you are not getting an engine fault warning? If no water in oil, get engine to ops temps and pressure--then look for leaks, engine dash heater, aqua-hot, radiator. Burning it--head gasket or EGR--harder to detect.

[hastemaker]

Check the intercooler, this mounts on the heads & is cooled with water from the radiator & looks just like a radiator (on the insides) & if it gets a core leaking it will put into the piston cylinder & will be blown out the exhaust, so you will never see a leak.

I had a 400 Cummins in a car hauler truck that was using water without any leaking that could be seen, I would ad a can of K&W sealer to the radiator & it would stop using water for awhile but start again, after many months of doing this I lost a cylinder one day, but was able to return home on 5 cylinders, pulled the intercooler off the heads & the K&W sealer had completely seal the intake for that cylinder & that was how I found out my water leak was the intercooler.

[Jeff753]

additionally the seller has driven it 8k miles since 23 when the 7 gallons was added and the reservoir tube was observed full....so its probably not the motor??

[Gr8bawana]

Walk away now. It's not like the antifreeze mysteriously disappeared, it went somewhere.
That could be why it's being sold.
I wouldn't buy something that might end up being a can or worms.

[wolfe10]

Originally Posted by hastemaker

Check the intercooler, this mounts on the heads & is cooled with water from the radiator & looks just like a radiator (on the insides) & if it gets a core leaking it will put into the piston cylinder & will be blown out the exhaust, so you will never see a leak.

Suspect you are referring to the OIL COOLER, not intercooler.

[justcheckn]

Check the rubber seals on the reservoir cap
This happened to me. The upper gasket was split and not sealing on the neck. FYI. Tried to find the cap online and it was $75 everywhere I checked, got one from the auto parts store for $8. The split allowed the coolant to leak out through the overflow tube and Yes the replacement cap was the correct pressure rating and fit correctly.
Bobby in Colorado.

[jacwjames]

I'd have a Cummins shop provide a mirror image of the ECM. This will have the Abuse History showing if the engine ever got hot along with a bunch of other criteria (oil pressure, etc).



I'd do an oil sample of engine and transmission.



Not sure what the coolant capacity in that motor but I would be surprised that the amount didn't trigger some alarms.

[OMMM4747]

Hmm, a one-time occurrence or signs of a poorly-maintained rig. IMHO 7 gals is a lot! What other hidden problems may you be purchasing? Highly recommend a professional inspection to include an engine shop. Hindsight is always 20-20!

Good luck

[hastemaker]

Originally Posted by wolfe10

Suspect you are referring to the OIL COOLER, not intercooler.

No I am talking the after cooler, that bolts to the heads & has a tube that connects the turbo.