Engine coolant question

[Ter Uh P]

We just purchased a 2018 Foretravel Realm with 18k miles, 605 HP Cummings engine.

The coolant level in reservoir peep sight was not visible so I added exactly one gallon 50/50 mix to the reservoir which brought the coolant level to full cold mark and peep sight was full. Drove the coach from Ca. to La. I checked the peep sight today and it wasn’t visible. Added exactly one gallon to fill the reservoir to the full cold mark and the peep sight is full again. There are no visible leaks, no making engine oil. I’m thinking the expansion inside the reservoir is greater than design and that one gallon is expelling through the overflow tube at full operating temperature. What’s everyone’s experience on this subject?

[wolfe10]

First (inexpensive) step is to replace the radiator cap.


If not holding pressure, can allow of excessive flow to overflow reservoir.

[Dutch Star Don]

Was the coolant changed by the seller or by you after you bought it. If it was, it's a BIG system and it can be burping out air in sytstem.

[ArtJoyce]

Im thinking its a leak. Now maybe you were down 2+ gallons and one was air in the coolant system and you burped out the air.

I had a leak of gallon every 6k miles. Could not find the leak until one day i'm changing the oil on a hot engine and one drop of coolant fell on me. I had gate valves that the chassis manufacture installed so the coach manufacture could add the dash heat and engine coolant exchange into the water heater. The leak was at the gate valve packing nut. I found all 4 of my gate valves were wet at the packing nut. 1/4 turn on the nuts and no more leaks. I figure as it got hot and more presure it would leak more, but when it cooled down at slower speeds and backing up my drive. The presure dropped and no signs of a leak on my concrete driveway.

I just bring it up because it can sometimes be hard to find any signs of a leak

[High Road Travelers]

If you are going back to CA and haven't found the leak, you could stop off in Nacogdoches, TX and get the factory to check it. Also Motorhomes of Texas is very close to them and they could probably help.
Thanks,

[RichardE]

I use white paper towel pieces zip tied at suspected leak locations to check for leaks.

[Harleytoter]

I found a leak at the aquahot loop for the engine preheat. The previous owner had used a regular hose clamp on the check valve instead of a constant pressure clamp. When it gets hot would expand and as it cooled it would drip.

[Ter Uh P]

Originally Posted by wolfe10

First (inexpensive) step is to replace the radiator cap.


If not holding pressure, can allow of excessive flow to overflow reservoir.

I will do this

[Ter Uh P]

Originally Posted by Dutch Star Don

Was the coolant changed by the seller or by you after you bought it. If it was, it's a BIG system and it can be burping out air in sytstem.

I don’t think he changed the coolant, reason being only 18k miles

[Ter Uh P]

No more CA for me!

[BigEvi]

I had a very slight coolant leak. In cold weather the radiator cores would shrink and loosen on the side tanks on the radiator. It only leaked when cold. Would take 5000 or so miles to leak a gallon...but really only in the colder months. I put several bottles of Kseal in it while hot. Sealed it right up perfectly.



-E

[Tha_Rooster]

Originally Posted by Ter Uh P

We just purchased a 2018 Foretravel Realm with 18k miles, 605 HP Cummings engine.



The coolant level in reservoir peep sight was not visible so I added exactly one gallon 50/50 mix to the reservoir which brought the coolant level to full cold mark and peep sight was full. Drove the coach from Ca. to La. I checked the peep sight today and it wasn’t visible. Added exactly one gallon to fill the reservoir to the full cold mark and the peep sight is full again. There are no visible leaks, no making engine oil. I’m thinking the expansion inside the reservoir is greater than design and that one gallon is expelling through the overflow tube at full operating temperature. What’s everyone’s experience on this subject?

What kind of coolant did you add?

[Ilvmygt]

You could also add a temporary catch tank to the overflow tube to see if it catches any coolant.