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RVing message boards => Tech Talk => Topic started by: Kim (skyking4ar2) Bertram on September 10, 2017, 11:41:45 AM

Title: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on September 10, 2017, 11:41:45 AM
Long read….

We have a 450hp ISL 9 Cummins, rear radiator, in our 2012 Thor Tuscany 42RQ. Five years on the road full time and 42,000 miles with zero issues with coolant of any kind.

Coolant is disappearing from my system and Freightliner 24/7 and Freightliner shops have been engaged and we are still struggling to isolate the issue. The story follows and I am looking for any user insight into the issue.

The issue began with a top radiator hose clamp that was loose, forcing a catastrophic coolant loss, and a resulting $1,000 wrecker ride. Farmington Freightliner replaced the clamp, refilled the radiator with Alliance 50/50 coolant, pressure tested the system for leaks and off we went.

Over the next 5,000 miles from NM to Alaska, we would periodically get a low coolant light, stop, refill the tank with the same Alliance coolant, 50/50, and proceed. Over the course of the trip and back, this issue continued to occur, especially on long grades, and ultimately with a stop engine light. During these times, and with a five year history of driving this rig, I never saw abnormal temps, and typically any time temps rose to 212 digital, the fan would kick in, and the temps would immediately respond lower.

Just in case, I replaced the radiator cap with a 16# Freightliner cap after recommendation from FCCC Service, while getting ready to cross back to the US.

Fast forward to returning to the US, we made a stop at Freightliner Great Falls, MT, and had the shop attempt to diagnose the continuing coolant loss, usually 16 to 32 oz every couple hundred miles. The pulled the EGR cooler tube to see if the EGR cooler had a leak and determined it did not.

I once again pressure tested the radiator and cap, and there was no leak down. I also tried to clear the radiator coils from the exposed side with biodegradable solvent and a water hose.

We drove down to Idaho Falls, ID Freightliner and once again had a full diagnostic run per Cummins spec for a coolant loss. He ran a bubble test for compression leaks. No evidence of water in engine oil or transmission fluid. We replaced the low coolant probe, refilled the coolant tank, pressure tested again, turned off the heater valves in case the 40’ heater hoses were leaking, and once again went down the road. No leaks or wet spots were observed anywhere during this diagnostic, nor had they been observed at any time previous.

A regen was done in the shop and the tech indicated there was no way we could get those kinds of exhaust temps with a head gasket or cylinder head issue. Every Cummins test on the laptop showed everything normal.

We are now in Gunnison, CO, I am still having some coolant loss, especially after climbing at elevation, and yet the engine temps continue to look normal, sometimes going as high as 217, but always falling back around 210 or below.

Given all of that, I am now suspicious that the one thing that has not changed is the coolant. I went five years on my old coolant without issue, had it tested in the spring at Empire Freightliner in Pensacola (which was before we blew the hose) and in all of that time had used just a little over a gallon over that time period.

Is it possible that coolant is not up to spec even though it was the Freightliner shop’s preference? At this point, it is the one thing we have not changed out. I will tell you that on the last hot fill, the tank gurgled and steamed for almost 10 minutes before I added coolant again. Is it possible we are vaporizing coolant which escapes via the overflow tube and we never see the mist?

I have never been so vexed and had so many people involved and still have the problem unresolved. I have to pull two more major passes this fall, and while I can drop the towed, that may not prove anything.

All told, I am almost $5,000 into this coolant issue without a resolution. Surely, there is a logical explanation somewhere.

I have an open case with Freightliner, but it won’t hurt to get some user experience.

Thanks for your thoughts.

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Alfa38User on September 10, 2017, 11:50:15 AM
Cracked head or head gasket??  Hope not though!!!
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on September 10, 2017, 12:03:59 PM
See above - bubble test completed without issue. No compression leakage into coolant.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kevin Means on September 10, 2017, 12:29:36 PM
Kim, does your overflow holding tank have coolant in it ? The internal chambers in Cummins engines, apparently, hold a lot of coolant, even when the coolant has been drained from the radiator. Is it possible that your coolant was never topped off to begin with?

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Gary RV_Wizard on September 10, 2017, 12:47:59 PM
I don't think Kim has an "overflow tank" like in a car system. The Freightliner system uses a reservoir, which is pressurized just like the radiator itself. The reservoir also handles coolant expansion, so there is no overflow mechanism like on a car.

I don't see how the coolant itself could cause the problem. The Alliance diesel coolant is just one of the major brands, private labeled with Freightliner's Alliance brand name. Last I knew it was actually Old World's Fleet Charge, one of the most widely used diesel coolant formulas.

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on September 10, 2017, 01:03:55 PM

This system does not use a coolant overflow system. It has a pressurized reservoir which in turn has a simple overflow tube that exits at the bottom of the radiator. As you loosen the 16# radiator cap, the pressure releases via the overflow (or in your face if you not smart enough to just crack it).

You can fully pressurize the system at that cap and there is no leak down which rules out a crack in the plastic reservoir itself.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: jubileee on September 11, 2017, 12:14:27 AM
I bought a new Peterbilt (03) with 550 Cat that took a 1/2 to 1 gal of coolant every 5000 miles from the day I drove it off the lot. Peterbilt and Cat gave up trying to solve problem. I had Cat's 5 year/500,000 mi warranty, but Cat said they would honor the coolant loss problem ( if it caused other problems) as long as I owned the truck.
At about 3 years, I was adjusting the waste gate on the turbo, and I noticed some whitish build up at the base of a silicone hose in between turbo and block. Lo and behold, I found the problem. Turned out the hose nipple that screwed into the head had a hairline crack that extended between the bottom of the hose and the threads. It must have only opened up at around 200 degrees or above and the leaking coolant was instantly vaporized by the turbo. I always thought I could get a whiff of antifreeze after a hard pull, but never sure. I don't know how many times I pressurized that system to 18-20 lbs., let it sit all night, and hoped to find a drop or two of coolant the next morning. Never happened. Anyway, that's my coolant loss story that the dealer and engine manufacturer could not solve. Also, Cat had that truck on the dyno once to try to find if it was a "hot" leak. Don't know how they missed it.

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on September 11, 2017, 09:08:17 AM
I don't think I would mind a coolant loss that was easily replaced. My particular problem is that when the coolant is down as low as 16 oz, on a grade, it will trip the low coolant sensor, and if I don't crest the hill in about 30 seconds, the stop engine light comes on. That, in itself, is not the worst thing, except when it happens on a two lane with no shoulder.

I, too, think the coolant is getting vaporized, and I will certainly go down that road with Freightliner and discuss the turbo. I had hoped the EGR cooler was the primary plumbing, but I need more information. Like you, I have imagined a whiff of coolant on a long pull, but talk myself out of it.

This cannot be the first time someone has run into a problem like this. Thanks for your story, it just might help someone get on track with a solution.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kevin Means on September 11, 2017, 11:17:34 AM
Poor choice of words on my part Kim... that reservoir is what I was talking about. Jubilee's experience with a similar problem is interesting, but that would sure be tough to diagnose and locate. Too bad there isn't some kind of dye you could put in the coolant - like we do when trying to locate a leak in the air conditioning system.

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Boonieman on September 11, 2017, 08:46:51 PM
One clue is you mentioned you heard the radiator "gurgling" for about 10 minutes before removing the radiator cap. At 16# pounds ( the pressure rating of your radiator cap) water won't boil until around 250 degrees F. But you said you already replaced the cap, but maybe for some other reason your system is not holding pressure during operation, which would let the liquid boil at a much lower temperature, and vaporizing off as you suggested. Difficult problem, but go back to the original radiator hose leak. Something obviously changed right there, because you had no prior issues.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on September 11, 2017, 09:14:12 PM
As noted, and after three different radiator caps, three pressure leakdown tests, and a bubble test at temp, there is absolutely no indication of a pressure leak, in or out.  >:(
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Ken & Sheila on September 11, 2017, 10:40:34 PM
I assume that every hose clamp in the coolant system plumbing has been checked, but if were me (and in this case it was a few months ago) I would personally check every clamp. I did find a clamp from 1 1/2inch hose to pipe that while not damp showed signs of maybe a leak. Tighten the clamp and 95%= of my coolant loss stopped. Since then I've lost maybe a quart+ over 9,000 miles this summer. Not fun climbing around the engine looking for leaks but I did it from thee back, from underneath and from the top to hatches. Used a powerful LED flashlight.

Title: Re: Cummins ISL 9 Coolant Issue
Post by: SargeW on September 12, 2017, 07:11:39 AM
I too am thinking vaporizing fluid. I had a similar issue with my first car when I was a kid. Went for months and could never find it. Finally accidentally solved it while putting a new thermostat one day. The thermostat housing had a hairline crack under one of the bolt holes that would only open up under heavy load. Since it was on the thermostat housing, when the thermostat was closed, no fluid was being passed to leak out. Only when the thermostat opened AND it was under heavy load did it leak out and burn off.

In my experience when a radiator gurgles it is because air is getting into the system from somewhere.  A crack, a failing hose or hose clamp. High heat and expansion of the part lets the fluid out, and air in.  I too would recommend changing all the hoses and clamps on the motor as a starting point.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Boonieman on September 12, 2017, 08:50:44 AM
Might not have found any indications of a leak, but you definitely have one or you wouldn't be losing fluid. A couple things, I just got done working on my old 8N Ford tractor and part of what I'm doing involved having to drain the coolant from the block. When I drained it the antifreeze looked nice and green like normal. Some of it missed the bucket and went on the floor. Right then, I got a phone call and had to quit, so I locked up the barn with a mental note I had to wipe that up because sometimes the dogs come in there with me while I'm working. I went in the next day and the water/antifreeze mix had evaporated overnight. Any proper antifreeze mix I ever dealt with doesn't evaporate, at least overnight, but mine sure did. It tested ok with one of those little squeeseball testers. So, it's feasible that you are leaking some and it flashes off and you never see signs of a leak. The other thing that comes to mind, is in my job before I retired we used large heater exchangers. As routine maintenance these would get pulled and a spare put in. The spares where always supposed to be hydro water pressure tested by the maintenance guys. On several occasions the spares leaked after being installed. After many accusations that the mechanics weren't actually doing the pressure tests, investigation found that they were actually conducting the tests, but at high pressure. So they had a 300# gauge on there, pumped up the pressure to 200#, held that pressure for 2 hours and called it good after no visible loss on the pressure gauge. We found out that on very small leaks, the movement on a gauge with a measurement span that large wasn't noticeable by the naked eye if it lost a little bit of pressure, unless the test was of very long duration. We changed the test method to also include a test using inches of water vs psi. At those low pressures with with a different gauge ( we used one with a 10 inches of water range) even very small, slow leaks were then detectable on the gauge. If I remember right, 28 inches of water = 1 psi, so we were basically testing at less than 3 psi.
I too hate these seemingly unsolvable problems!! 
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on October 01, 2017, 01:00:27 PM
Now for the rest of the story! (I miss that guy...)

After I sent the full epistle of this journey down Prestone lane to Freightliner's head tech advisor and a subsequent follow up phone call, I present the following information.

At the factory, eleven (11) gallons of coolant is pumped into the system at 3 gallons per minute to avoid any air pockets. That's important.

Flash back to radiator hose clamp repair, and after that clamp was installed, the tech brought out six gallons of 50/50 antifreeze and five gallons if distilled water, like he knew that was the capacity. I was standing with him when he started to refill the radiator.

First red herring for me - there is a placard at the radiator that gives specific instructions on how to refill and purge the radiator. Written on it in Sharpie was "26 qts". I assumed that means put 26 quarts (6.5) gallons back in the radiator. Wrong! Smudged below that was the word "oil". Not seeing the oil note at the moment, I assumed we're putting 6.5 gallons back in the radiator.

Here's the math part - the tech puts four gallons of 50/50 of the six on the ground in, and three of the water, and the reservoir tops. Make a note, there's two gallons of 50/50 on the ground and two gallons of water. We crank it up, fine, we pressure test for 30 minutes, fine. We load the spare 50/50 and the water in the storage bay, and off we go.

You've figured out already we probably never had 11 gallons in the radiator.

Freightliner also says they have seen coaches run out 3,000 miles before they burp all the air. I think that's crazy, but that's their experience.

Over the course of the next 5,200 miles, I end up mixing and adding a quart or more on a regular basis.

On the way into Gunnison a couple weeks ago, pulling a pass, we get another low coolant, stop engine event, and I fill some more, still have maybe a gallon of mixed coolant and water left afterwards.

In Gunnison is when I get FTL on the line and we talk about the problem. I use the last gallon of coolant mix and fill the radiator and FTL says fill it to the top, past the MAX COLD line. At this point, I know for a fact that 11 gallons of coolant has gone into the radiator since the hose blew.

Two weeks later, I have to climb Monarch Pass, ~11,000 feet, and Poncha Pass, ~9,000 on the way to Taos. I decide this is the ultimate test if we have a fix or not, so I have Christi drive the Jeep, instead of towing, and I pull Monarch Pass and meet her at the top. Check the coolant level, just about right where I started. Fabulous! Absolutely no indication of any temp anomalies crawling the steepest part of the pass at 40mph, so we hook up. I pull Poncha Pass towing, stop at the top, still no issues, still full coolant.

Pull into Taos, still full to the mark on coolant, very normal temps.

So, 5,200 miles later, this is the best we have looked, we'll see if there's any more coolant to be added, but maybe, just maybe, the fix is in!

A long story with maybe a happy ending! And don't we all like happy endings?  :))

More than one adult beverage has since been consumed.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kevin Means on October 01, 2017, 01:34:06 PM
Thanks for the update Kim. Glad it's resolved. (Bet you are too!)

Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on October 01, 2017, 03:16:39 PM
Honestly, Kevin, for as long as this has plagued us, it ain't over 'til I get down to the Florida Panhandle for the winter. And I have Gaffney, SC as a Plan B. But I am WAY farther along than I was a month ago!
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Ken & Sheila on October 01, 2017, 03:27:48 PM
Kim, Good News.
Hope the coolant issue is behind you.
I know how frustrating it is to chase these problems.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: SargeW on October 01, 2017, 08:11:25 PM
Good news Kim. I love it when the problem gets fixed without a big repair bill attached.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: kdbgoat on October 02, 2017, 08:40:33 AM
Now the fun part is checking the coolant to see where the freezing point is, and SCA's if used in the coolant. Hopefully they are in spec, and you don't have drain and add more coolant and less water.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: Kim (skyking4ar2) Bertram on October 02, 2017, 09:58:06 AM
By volume, 50/50 ethylene glycol coolant will take me way below 0 degrees Fahrenheit. And as full timers, we follow the sun.  8)
Title: Re: Cummins ISL 9 Coolant Issue
Post by: ChasA on October 02, 2017, 05:59:21 PM
Kim, are you aware that the antifreeze also raises the boiling point of your coolant?  You should make sure your coolant is mixed at the proper proportions.
Title: Re: Cummins ISL 9 Coolant Issue
Post by: kdbgoat on October 03, 2017, 06:07:35 AM
Kim, are you aware that the antifreeze also raises the boiling point of your coolant?  You should make sure your coolant is mixed at the proper proportions.

 :)) Just because it seems like everything went in at the proper proportions, doesn't mean that it actually did.