Non serviceable level sensor inside that surge tank... Best you can do is take tank off put water in and shake try and get sensor to work again(hasn't worked for me yet though)..
Rockauto or amazon probably has best prices for new unit, i wouldn't get a used myself.
I lived with the message for many months before until found one on sale because I'm cheap LOL.
It's a fairly common occurrence to have that sensor fail...

 

Non serviceable level sensor inside that surge tank... Best you can do is take tank off put water in and shake try and get sensor to work again(hasn't worked for me yet though)..

Thank you. Same here. My tpms also isn't working so I just spam the info button until it all goes away haha. But coolant is a higher priority than tire pressure, so I'd like to get that fixed if possible. I'll try that method and see if it works.

 

2005 Cadillac DeVille Base

My DIC keeps showing "check coolant level." The coolant level according to the reservoir is fine, but I added some thinking maybe it was a tad low. Still saying check coolant level. I then filled it to the top line, which according to the manual is the line it should be at while hot, not cold. Still told me to check coolant. So I thought "okay, maybe it is telling me the level is too high." I drained all the coolant and added fresh prestone dex-cool coolant. Same thing.

So I have came to the conclusion I need a new coolant reservoir level sensor, but I do not know where it is. I assume it is inside the reservoir itself, and is it serviceable or do I need a new reservoir tank?

(Everytime I messed with the coolant I let it get to operating temp before messing with it again)

As posted you can remove, add water and maybe soap, shake & see if that helps. Before you get to that stage I'd suggest you remove the plug from the tank, jump the wires with a paper clip and see if the light goes off. Another trick is to give the side of the tank (nearest the the float) a couple of good whacks with rubber mallet. If all else fails, the tanks aren't that expensive and the install isn't even a one beer job.

 

"A one beer job" ha. I like that. Tomorrow I'll see if that helps. I'll price one out at some local auto stores since my buddy works there and gets 30% off, so it may be worth it to just buy a new one.

 

The coolant level sensor is a magnetic reed switch acted upon by a float/magnet. With some searching in these forums and the internet you can find replacement sensors. It snaps into a recess in the bottom of the surge tank.

Replacing the entire surge tank is not a bad idea, though - they do discolor and get brittle. Same for the plastic T fitting under the surge tank.

Use the FULL COLD legend and arrow molded into the surge tank top to find correct ambient cold fill line - about the tank mid-seam.

Here's a cutaway of the tank float and level sensor connection.

The UltraPower is just fine - original "AC Delco" supplier. RockAuto does not list the level sensor as a separate part but it IS replaceable.

2005 CADILLAC DEVILLE 4.6L V8 Coolant Reservoir | Shop Now at RockAuto

Cooling System Parts and More for Your 2005 CADILLAC DEVILLE at Reliably Low Prices. Fast Online Catalog. DIY-Easy. Your Choice of Quality. Full Manufacturer Warranty.

www.rockauto.com

 

Hi guys,

Greetings from Baja, MX. Nowadays, I'm also getting that message and I noticed that the connector was not plugged at all. I managed to reconnect the cable to the tank but the situation was unchanged.

Sadly, I rushed in almost panic mode to my trusted shop and told the technician to replace the old juice with fresh Peak Dex-Cool coolant: I feared the worst given the "reputation" that the Northstar engines have for overheating. And after all the above, I still have the same warning on the dashboard every time I start the car.

Now, after reading this thread, I'm starting to believe that the culprit might be the tank itself, because it's faulty. I mean, new coolant won't hurt my DeVille, right? And my technician told me beforehand that everything was working as intended (radiator, fan, temps within expected range, etc.). To reassure myself, I told him to add new coolant anyway, and so he did. My peace of mind cost me ~$60 USD 😅

I will look for a new coolant tank and will take it to my shop for installation, during my next rotation home.
Thank you for your time.


Have a great rest of the day!