Interesting Occurrence

[SuiteSuccess]

Was pulling out of a campsite that was uphill and little bit side hill. Base was gravel and sand and wheels started to spin and then got traction. Truck shook a bit. Got immediate low coolant alert, engine derated, then shut down in less than 15 seconds. I had pre-flighted before leaving and knew had no leaks and plenty of coolant. Rechecked and all good.  Tried restart and started without issue.  My supposition is coolant sloshed around enough it triggered low coolant sensor to cause shutdown.  BTW I replaced the sensor several years ago so think it’s ok. Thoughts?

Edited January 28, 2022 by SuiteSuccess

[SuiteSuccess]

BTW drove 120 miles after without a glitch. 

[Darryl&Rita]

You know the condition of your truck better than I, but that sounds plausible.

[SuiteSuccess]

1 hour ago, Darryl&Rita said:

You know the condition of your truck better than I, but that sounds plausible.

Interesting pulled the code on diagnostics and it showed inactive. Just a gremlin hopefully.  Hopefully helpful info for others. 

[Alie&Jim's Carrilite]

If the coolant in the overflow had sloshed far enough from the sensor it will throw a code.  Even on my old '98 with a Cummins, it has done it.  Off camber/canter at a campground and bounced a tire over a rock.

 

[noteven]

Yes the low coolant sensor is happy to do that on the Modern Diesel Truck.  

Running it a bit over full (it will self adjust out the overflow) will allow you to show off by patching out leaving a campsite without embarrassing codes and derates 🤣

[Brad & Jacolyn]

Mine was doing that and at the most embarrassing times. I started running the coolant level a little higher and the problem stopped. So I'm assuming that the coolant sensor did not like the level I was using.

If it really is a bad sensor AND you are sure the coolant level is good you can pull the wire off the sensor and you are on your way.

Edited September 24, 2021 by Brad & Jacolyn

[DJohns]

I wonder how many people have coolant sensor problems compared to real low coolant issues. Just because the over flow tank is low doesn't mean the radiator is.  Especially with motorhomes  but trucks also it seems like there are lots of issues with coolant sensor.

[noteven]

12 minutes ago, DJohns said:

I wonder how many people have coolant sensor problems compared to real low coolant issues. Just because the over flow tank is low doesn't mean the radiator is.  Especially with motorhomes  but trucks also it seems like there are lots of issues with coolant sensor.

Kenworth taught us the tank with the sensor is a safer way to check (see through) and add coolant if necessary vs opening the radiator cap itself. On a hot engine especially you aren't crawling up off the ground to stick your face above a rad cap.  You check level by looking and replenish standing on the ground.

Also radiators don't have the big top tank any more due to the underhood "cooling package" space being used for larger cores packaged in a lower nose. 

Edited September 25, 2021 by noteven

[rickeieio]

Agreed.  Often the reservoir tank is a distance away from the radiator and much lower than where the top tank would be.  I had a John Deere which had the tank about 2' behind and a foot below.  You could check it just walking around the machine while doing the pre-flight.

That said, many machines don't have a sensor.  None of my Deeres did, nor have any of our cars and pick-ups.

[geodog1]

My 2003 d12d does not have a sensor. The wires are there but it appears someone did not put a sensor in when replacing the overflow tank.

 

 

ShortyO

[Parrformance]

On 9/24/2021 at 10:02 AM, Brad & Jacolyn said:

Mine was doing that and at the most embarrassing times. I started running the coolant level a little higher and the problem stopped. So I'm assuming that the coolant sensor did not like the level I was using.

If it really is a bad sensor AND you are sure the coolant level is good you can pull the wire off the sensor and you are on your way.

I looked at my overflow jug over the radiator while fixing the fan issue.

Connector was rotted in half, not connected. No indication on the dash at all.

[SuiteSuccess]

Updating this thread.  Pulled truck out of storage to drive and get some fuel. As I was leaving fuel stop about 1/4 mile away got low coolant alarm, derate and 15 secs later, shutdown.  I had “pre-flighted” truck so knew coolant level was okay.  Made it to shoulder, waited couple of minutes and truck restarted without issue and made it back to storage.  This time was on flat, level road and no sloshing.  What’s up?  Well, hit Google and found out in my D12 the overflow tank sensor is a resistance sensor that responds to a float ring that is magnetic.  My tank has not been changed in the 12 years I’ve owned the truck (the coolant has but is overdue).  Apparently some grunge can get on the float and it will stick setting off the alarm.  My plan when warmer is to change out tank, sensor, coolant, and wiring to hopefully solve the issue.

[rickeieio]

Nice update, and also nice solution, assuming that fixes it.

[SuiteSuccess]

3 minutes ago, rickeieio said:

Nice update, and also nice solution, assuming that fixes it.

Hope so.

[rollinbrian]

5 hours ago, SuiteSuccess said:

Updating this thread.  Pulled truck out of storage to drive and get some fuel. As I was leaving fuel stop about 1/4 mile away got low coolant alarm, derate and 15 secs later, shutdown.  I had “pre-flighted” truck so knew coolant level was okay.  Made it to shoulder, waited couple of minutes and truck restarted without issue and made it back to storage.  This time was on flat, level road and no sloshing.  What’s up?  Well, hit Google and found out in my D12 the overflow tank sensor is a resistance sensor that responds to a float ring that is magnetic.  My tank has not been changed in the 12 years I’ve owned the truck (the coolant has but is overdue).  Apparently some grunge can get on the float and it will stick setting off the alarm.  My plan when warmer is to change out tank, sensor, coolant, and wiring to hopefully solve the issue.

Interesting,  I've been driving around disconnected and doing visual checks on mine as the derate 30 seconds after pulling out is not fun.  Replaced the sensor but no better,  tried to top off the tank but it levels back down.  Adding new tank to the maintenance cycle!

[lappir]

20 hours ago, rickeieio said:

Nice update, and also nice solution, assuming that fixes it.

I agree with what Rick wrote. 

It's been several years since my first trip to Colorado and the "Pony Pack" mounted to the truck rails developed a leak and caused an issue with my coolant level. A couple of years later I found one of the tanks had a small leak also, luckily I was near a dealership and replace it. 

I had my coolant checked 2 years ago and the mechanic said I had a few more years with my type of operation. I'll have him check again the next trip there. 

 

Rod

[Cotreker]

On 9/23/2021 at 4:15 PM, SuiteSuccess said:

Was pulling out of a campsite that was uphill and little bit side hill. Base was gravel and sand and wheels started to spin and then got traction. Truck shook a bit. Got immediate low coolant alert, engine derated, then shut down in less than 15 seconds. I had pre-flighted before leaving and knew had no leaks and plenty of coolant. Rechecked and all good.  Tried restart and started without issue.  My supposition is coolant sloshed around enough it triggered low coolant sensor to cause shutdown.  BTW I replaced the sensor several years ago so think it’s ok. Thoughts?

I had same issue on my Volvo 670, darn thing shut down a number of times when I first owned it.  Tag on the top of the reservoir says "Fill to Brim".  Hard corners were setting off the low level alarm and shut the truck down.