LOSING COOLANT- no signs of a leak

[TonyMac]

I would have to ditto everything Country B has said, sorry about that. I too would try the pressure cap, and tighten all the hose clamps, look carefully for signs of leak, but it sounds like you've already done that so it's likely coolant going out the exhaust if it's not showing up in the oil. And maybe it's just me, but I would NEVER use any sort of coolant sealer. Find the leak and fix the leak and be done with it.

[Gorlininc]

Originally Posted by MSHappyCampers

Rick, I'm about as far from being a mechanic as possible, but that sounds like a serious problem! Hope it turns out to be something simple!

Thanks Joe
Me to.
Have a Merry Christmas

[Gorlininc]

Originally Posted by TonyMac

I would have to ditto everything Country B has said, sorry about that. I too would try the pressure cap, and tighten all the hose clamps, look carefully for signs of leak, but it sounds like you've already done that so it's likely coolant going out the exhaust if it's not showing up in the oil. And maybe it's just me, but I would NEVER use any sort of coolant sealer. Find the leak and fix the leak and be done with it.

I agree.

[oldguy70]

The way to tell if you have a blown head gasket or a cracked head is to check and see if you have bubbles coming out into your over flow tank. If you have bubbles coming into the over flow tank the air will push coolant out your overflow. If no bubbles check for
leaks again. Remember you have heater hoses running to the heater in the front. I had
a slow leak in my Dynasty and it was a loose heater hose clamp at the heater. Good luck

[Gorlininc]

Originally Posted by oldguy70

The way to tell if you have a blown head gasket or a cracked head is to check and see if you have bubbles coming out into your over flow tank. If you have bubbles coming into the over flow tank the air will push coolant out your overflow. If no bubbles check for
leaks again. Remember you have heater hoses running to the heater in the front. I had
a slow leak in my Dynasty and it was a loose heater hose clamp at the heater. Good luck

There are no bubbles in the overflow tank. I checked that yesterday. I also pressurized the cooling system to 13 pounds and it held for over an hour.

[Outbound]

Metal expands when it is hot, not sure if you have but can you let engine run to raise temp for a visual check.

[Gorlininc]

Originally Posted by Outbound

Metal expands when it is hot, not sure if you have but can you let engine run to raise temp for a visual check.

I’ll try it again tomorrow and let it heat up to full temperature. I didn’t think of that. Thank you

[guardrail53]

Did you check the freeze plug at the front of the motor (the back side in a MH) in behind the water pump, more to the center of the motor behind a pully?
There was a thread on here a year or so back of those rusting out! Just one more place to look!
I think with that much coolant loss, you can rule out leaks, unless you have more than one? I would think you could slide a big piece of cardboard under the MH, let it sit for a few days, as cold water leaks, are very hard to find! Slide one piece under the front where the heater core is, and one under the motor area?
I'm hoping for you to find a easy fix, but it does sound like you are burning the coolant! Good luck! Rail!

[1doodadd]

Has anybody said or thought about the trans oil cooler? Have you checked the trans oil for contamination? If not that, then My bet is the Head Gasket. I have had it happen to 2 cummins engines I ran years ago. Hydraulic on #4 cylinder on 1 rig.

[Bubba1]

If you still have the original aluminum radiator, check around the upper radiator hose neck on the radiator. Mine developed a leak on the bottom side of the neck where it was welded to the radiator tank. The leak didn't show up until the engine was over 195 degrees. Never saw any coolant on the ground. When the radiator was pulled, the leak trail was very obvious once the fan shroud was pulled.



Mike H

[RobRoy]

Pressure test the cooling system....Does it hold pressure?

If not ?...Do a thorough visual check from stem to stern for traces of coolant.

Pressure test the cooling system cap for proper function and pressure rating.

Is the cooling fan functioning correctly once warmed up?

If you pass these tests?... I would purchase this and test further.

Diesel test fluid https://www.amazon.com/Lisle-75730-D.../dp/B000I16L90

You will also need this https://www.amazon.com/OEMTOOLS-2714...PS6K0RTMMP3KT0


If it test's positive for combustion in the cooling system...I would also have the oil analyzed for contamination first, you certainly would not want to put $3 -$5k in the upper-end repair only find out your engine has ingested enough coolant to start taking out the lower end

https://www.blackstone-labs.com/


Happy Trails

[Gorlininc]

I’ll do that.
It does hold pressure when pressurized.
Can’t find any traces of coolant anywhere.
I’ll try getting a new radiator cap. Cheap idea.

I’ll get the diesel tester. I’ll order it today. I’ll post the results.
Thank You
Merry Christmas

[TomAndPeg]

Does your ISC have a coolant filter? That is a common point of leak/failure in the ISL.

[Outbound]

Does anyone know what would be the most common factor to crack a head on one of these monsters, I know overheating is a major one. Is one size/hp motor more apt to crack a head as other size/hp motors.