Consistent Low Coolant Warnings

[enmity02]

I have a 2017 Silverado 3500 Z71 LTZ Crew Cab Midnight, I seem to be getting consistent low coolant warnings, the actual fluids are fine. The dealer has looked at it and found a bunch of errors but they all relate back to an unknown error and that GM is working on the issue. Anyone else having this issue?

 

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[COHauler]

Check your degas bottle, float might be stuck. Rubber mallet and swinging motion can cure most any problem.

[tprayner]

I am interested in knowing what the fix ends up for this as I am having the same issue. Sensor has been replaced once, and is back in the shop again.

[1st diesel truck]

Hi all, I just wanted to add something's to see if it may help others out with the low coolant concerns.

 

Though the coolant level may not look low, it most likely is and there probably is an air pocket in the cooling system too...And it most likely left the factory like that... It took two tries for my dealer to look further into the situation regarding my same coolant level low message I had.

 

Bought my 2017 GMC denali 2500 HD 6.6L on 5/6/17 and that night the coolant message came on....Brought the truck back the next day, service writer opened the coolant cap which turned off the message for two days and they/he didn't "see" the message on the dash or in the scan tool history. The first time around they did some inspecting, testing and I thought some air bleeding too but may not have at that time I'm suspecting now.

 

Two days later while still cold in the morning, the message came back on....Got to work, shut it off and message went away while warm/hot.....I also noticed from the beginning my temp gauge would fluctuate 5 - 10 degrees at idle or RPM which typically helps indicate possibly some air in the system.

 

But the first thought/consensus was we just all figured it's probably just a float type sensor moving with expansions from hot to cold, etc. and it would need a new sensor but they didn't just want to add a new sensor for no true reason until tested better.

 

Let the dealer keep the truck a few days to check things over. Turns out GM is aware of this potential issue and "I believe" they may even have 2 types of written TSBs regarding this coolant message due to what my service tech wrote on my work order when I picked the truck up and so far no message on the dash.

 

Below is a copy and paste of a TSB by a member on another board that is posting some copies of these TSB's for the new L5P engines...Search online, ( L5P TSB (service bulletins, recalls, updates) Postings of Tech Service info for any New L5P engine issues.) for other info such as this one 'And things like very high oil PSI while cold which is normal and nothing to worry about according to GM.

 

My service tech wrote the following:

Test drove 5 miles and no low coolant light on. Checked for TSB's and found 17-NA-110 for this exact concern.

From factory they are under-filled, Allowed to cool down completely and added 1 quart. Got to operating temp as to bleed air pockets and fill surge tank. Allowed to cool again and rechecked coolant level. It was low a quart from air bleeding out. No leaks present anywhere under vehicle or see any signs of leaks. Just air pocket. Test drove and no lights came on.

 

Notice the above TSB number 17-NA-110 and then below # PIP5487 which leads me to believe there may be two notices from GM on this.

 

I'll let you know here if my coolant message comes back on anytime soon but I honestly don't think it will + I haven't really yet noticed as much of an coolant temperature fluctuation.

The truck is getting ready to turn over to 500 miles soon but the first half of them seemed to be going back and forth to the dealer thus far. But that's okay because it gives more reasons to just drive this awesome truck.

 

 

#PIP5487: 2017 6.6L L5P Duramax Coolant Leaks - (Mar 16, 2017)
Subject: 2017 6.6L L5P Duramax Coolant Leaks


--------------------------------------------------------------------------------
Brand:
Model:
Model Year:
VIN:
Engine:
Transmission:

from
to
from
to

Chevrolet
Silverado
2017
All
All
6.6 L5P
All

GMC
Sierra
2017
All
All
6.6 L5P
All


 

Involved Region or Country
North America

Additional RPO/s:
6.6 L5P

Condition
A customer may comment on a coolant leak, coolant consumption or of a low coolant message being displayed on the Driver's Information Center (DIC).

Cause
This may be due to cooling system leaks or an improper coolant fill procedure.

It may take a few engine temperature cycles (from operating temperature to cold) for the coolant level to show a lower than normal level.

Be sure to complete the current SI coolant system leak checks and verify there are no external leaks.

Reference the locations below to aid in locating external coolant leaks.

If no external leaks are found, refill the cooling system following SI procedures for filling the cooling system.

Evaluate coolant levels after a proper coolant fill is completed.


Correction
If the diagnosis has lead to external coolant leaks or a coolant loss concern check for leaks in the following areas:

Object ID: 4747691Click here for detailed picture of the image.

Object ID: 4750018Click here for detailed picture of the image.

Welded flange leaking on the Exhaust Gas Recirculation (EGR) coolant return pipe. Refer to call out #1 in the above picture.

Object ID: 4747685Click here for detailed picture of the image.

Welded flange leaking on the Exhaust Gas Recirculation (EGR) coolant feed pipe. Refer to call out #2 in the above picture.

Object ID: 4747686Click here for detailed picture of the image.

Another view of the leaking welded flange on the Exhaust Gas Recirculation (EGR) coolant feed pipe. Refer to call out #2 in the above picture.

Object ID: 4749115Click here for detailed picture of the image.

Coolant leak at the O-ring seal of the Exhaust Gas Recirculation (EGR) coolant feed pipe. Refer to call out #2 in the above picture.

Object ID: 4749101Click here for detailed picture of the image.

View of a rolled or pinched O-ring at Exhaust Gas Recirculation (EGR) coolant feed pipe. Refer to call out #2 in the above picture.

Note: The leak shown above could only be confirmed after removing the front accessory drive bracket and alternator.

Object ID: 4750082Click here for detailed picture of the image.

Coolant leaking from coolant hoses at the Emission Reduction Fluid Injector (DEF Injector).

Please be aware of the following if there is a need to pressure test the cooling system:

Note: The radiator surge tank uses two different radiator surge tank caps. The radiator surge tank cap that vents pressure in the event of excessive cooling system pressure is located on the lower outboard side of the radiator surge tank (2). The radiator surge tank cap that is located on top of the radiator surge tank (1) is where the cooling system is filled and where pressure testing equipment is to be mounted.

Caution: The cap mounted to the top of the surge tank uses LEFT HAND threads. Turn the cap clockwise to remove the cap or counter clockwise to install the cap. Failure to turn the cap in the proper direction when installing or removing it may cause damage to the cap and/or the surge tank.

Refer to Cooling System Leak Testing (L5P) for more information.

 

Version
1

Modified

there are pictures along with this but they do not matter for u guys, but new engine, new problems are starting to show, ive had one all ready with a fuel line leaking. as on drivers side which was stupid easy to fix, but I wanted to do the passengers and remove cooler

 

 

High Oil Pressure during Initial Start of Vehicle - (Feb 23, 2017)
Subject: High Oil Pressure during Initial Start of Vehicle


--------------------------------------------------------------------------------
Brand:
Model:
Model Year:
VIN:
Engine:
Transmission:

from
to
from
to

Chevrolet
Silverado
2017
2018
L5P
All

GMC
Sierra
2017
2018
L5P
All


Involved Region or Country
North America and Israel

Additional Options (RPOs)
Equipped with Diesel 6.6L Engine (RPO L5P)

Condition
Some customers may comment on high oil pressure or that the oil pressure is "pegged" high during the initial start up of the vehicle.

Cause
When first starting the engine with cold oil, the oil pressure can be up to 100 psi or 690 kPa (full range of oil pressure gauge) at idle conditions. This is normal with cold oil and internal relief valves in the engine will be active. As the engine oil temperature rises, the idle oil pressure will reduce.

Correction
This is considered a normal condition and no repairs should be performed.

 

Edited May 19, 2017 by 1st diesel truck

[newdude]

OP have a look see at the post above mine.

[Peterd]

 

What was the solution???

 

Presently on a road trip. Second day after having driven 700 miles day one the low coolant light came on shortly after starting out. Hit dismiss and watched the gauge for a few hundred miles. Have now gone over 3000 miles in six days. Have not seen the low coolant msg on the DIC again. Should perhaps also mention the outside temperature during the past three days has shown 100 at times each day.

 

Yes I'd be most interested in the solution to the apparent faulty warning.

 

On the up side the 2017 is getting 1.3 miles per gallon more than the 2015 on a very similar trip.

[enmity02]

The dealer said they just topped mine off, I am now at over 10k and haven't seen the error in the last 3k.

 

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[1st diesel truck]

Just getting to 1,500 miles and the coolant message hasn't returned since they topped of the coolant and bled the system of air.

 

From my perceptive (plus take notice the cold temperature gauge reading in enmity02 photo above) the coolant message may only come "on" when the engine is first turned on while still "cold" plus on ours, I did take note of about a 5 - 10 degree fluctuation while hot which went from normal 210 down to almost 200 then back up.... All of which is now gone since the coolant service.

[jeez]

I just had the same problem. Dealer pressure tested it over the weekend, ran the system hot and found a defective lower radiator hose. Only leaked when it was hot and pressurized. Said it has about 8 connections on that hose. Dealer told me that hose was $295! Glad for warranties......

[EXSlider400]

Truck is almost a year old and already went through 1 winter but this popped up today. I’m going to top it off with coolant and see if it helps as I could not find any leaks. 

[Colossus]

if its still under warranty, I might take it over there have them do it and get it on record in case you are dealing with a long term issue here. 

[EXSlider400]

True. 

[Dirtymaxjman]

My 2018 was throwing low coolant warnings and when i had my oil changed yesterday they went to take the cap off and it was extremely difficult..my coolant system had built up negative pressure...so when they took the cap off he told me it was full and didnt need any..put the cap back on and whala!!..no codes today..maybe the problem..maybe not.

[paauto]

I was consistently getting the "Low Coolant" message, despite the surge tank being full and bleeding the system by slowly opening the cap when shutting down for the night.  Figured it must be a faulty sensor, so I ordered a new surge tank and installed it.

 

The sensor has a float that closes the circuit when full and opens when low.   Installation requires removing the cross brace, air filter housing and  loosening the battery so you can slide it forward to pull the surge tank.  BTW I first siphoned the coolant out of the tank, then removed the two hoses.  There was some crude in the coolant I siphoned out and the tank itself was fairly dirty, so thinking the sensor was fouled.  Anyway, got the new tank and everything re-installed.  Low Coolant light is off  (at least for now - fingers crossed).

[Dick Mountjoy]

Yes, our 2017 Silverado 2500 Crew Cab also has the same issue with the coolant warning light coming on.  We took it in to the dealer for a different recall issue and asked them to check it.  The dealer sevice department called to say the sensor was bad and the entire reservoir needed to be replaced.  Couldn't just fix the sensor.  Wanted $450.00 for parts and labor.  

Edited August 6, 2020 by Dick Mountjoy