Low coolant warning and reservoir questions.

[Musicars]

I purchased a 2006 Yukon Denali this summer and have been having a host of issues. Right now I'm working on a no heat issue that I'm worried is a head gasket issue. I'm going to try to tackle one aspect at a time so as not to get too far off track.

Does anybody with a 2006 Yukon know for sure whether or not there is a low coolant waning in DIC and if the sensor on the reservoir is supposed to be hooked up?

I drove the truck for a couple of months this summer and even towed a car with it. It never overheated and had no warnings. The truck came up from Texas and I thought I better check the antifreeze concentration. Turns out what I thought was an antifreeze line on the reservoir was just a stain. The system was a gallon and a half low. It also was mostly water so I never smelled any leakage.

So I went to check to make sure the connector to the sensor was connected. There is no connector and no wire. I even opened up the plastic "armor" around the wires and found no cut wire or indication there ever was a connector.

The second part of the reservoir issue is that the level I see on the outside does not seem to match what is in the system. I was letting the truck warm up and burp the air out after filling the system up. I had the cap off with the nose of the truck up a bit. As I was walking toward the truck I noticed coolant running out the bottom of the truck. The side of the reservoir showed slightly above the full line yet when I looked into the opening I saw it was full and coolant was running out the overfull tube. Since then I am sure I am low on coolant but the tank is still showing full. I assume the tank is chambered and coolant is trapped in an outer chamber.

Anybody ever experienced this?

Thanks for looking.

 

[Doubeleive]

it sounds like you are seeing a residual inside line (stain) from the outside of the tank, after some years or even months these tanks will get discolored a bit and will have a line on them that looks like the coolant level, I always have to bump mine a little sometimes to verify the level because when you bump it the liquid inside will move and then you can see the actual level, replacement tanks are $20-30 online and it will look like new again. as for the sensor at some point they moved those from the reservoir tank to somewhere else or it works in a different way I am not sure I haven't run into that problem yet with my 2012

 

[Musicars]

it sounds like you are seeing a residual inside line (stain) from the outside of the tank, after some years or even months these tanks will get discolored a bit and will have a line on them that looks like the coolant level, I always have to bump mine a little sometimes to verify the level because when you bump it the liquid inside will move and then you can see the actual level, replacement tanks are $20-30 online and it will look like new again. as for the sensor at some point they moved those from the reservoir tank to somewhere else or it works in a different way I am not sure I haven't run into that problem yet with my 2012

Your right it is (was) a residual line. Since then I overfill a tiny bit so I can see the line. The problem is that the level is not going down even though I am losing coolant. I going to pull the tank and check for a plugged tank or hose. I will eventually replace the tank. Not sure if I should go with a new GM replacement ($70 - $80) or save some money and get a Dorman ($35 - $45 around here). The tank actually has a spot that looks like it got sand blasted and is thin so it will definitely get replaced.
Thanks for the input.

 

[Doubeleive]

Your right it is (was) a residual line. Since then I overfill a tiny bit so I can see the line. The problem is that the level is not going down even though I am losing coolant. I going to pull the tank and check for a plugged tank or hose. I will eventually replace the tank. Not sure if I should go with a new GM replacement ($70 - $80) or save some money and get a Dorman ($35 - $45 around here). The tank actually has a spot that looks like it got sand blasted and is thin so it will definitely get replaced.
Thanks for the input.

the dorman is fine, they are a near exact replica of the oem one
how do you conclude that you are losing coolant if the level is not going down?

 

[Musicars]

the dorman is fine, they are a near exact replica of the oem one
how do you conclude that you are losing coolant if the level is not going down?

I caught coolant pumping out of the overflow and I have no heat just like when it was low a couple of moths ago. I also have a leak at the heater hose to heater line connection that is dumping coolant on to my right exhaust manifold ( I ordered a new hose for that ). The level in the tank will go up a slight bit when hot but is not dropping below full when cool even with a couple of weeks of visual coolant loss. Have not verified anything yet so I am checking the tank and lines now.

 

[mizzouguy]

The leak at your heater hose fitting could be part of the cause of your no heat issue. They have an o-ring inside which will dry up/crack, or if its been really cold out the hose itself could have started leaking. Especially if it is original and uses the crimp on style fitting. Depending on where it is leaking, it could be losing coolant and filling your heater core (or rear heater lines if it has rear heat) with air. Id guess a new fitting or two and problems solved.

 

[Musicars]

I removed the reservoir the other day to see if something was plugged up. I cleaned it out but only found a thin layer of of dark something coating the bottom. Didn't find any blockage or some kind of gunk to explain the issues I have been having. I checked the hoses that go to and from the heater and blew through one using lung power only and coolant flowed out the other hose with out any resistance. Put it back together and now the front heater works great, at least for now (rear still is cool).

Unfortunately, now I have a strong coolant smell about the time the thermostat opens. Can't imagine I'm that big of a blowhard that I could have damaged the core by lightly blowing through it. Maybe I dislodged some crud. Not sure but very frustrating. Too cold to be pulling a heater core.

Regarding the coolant warning sensor I originally asked about: The plug sticking out at the bottom of the reservoir is a dummy. It has been sealed at the factory. Apparently, GM still used the reservoir but not the sensor used earlier. I have found the same part number on other 2006 Yukon and Suburbans. So, I am still trying to figure out if there even is a low coolant sensor in a 2006.

 

[HiHoeSilver]

I removed the reservoir the other day to see if something was plugged up. I cleaned it out but only found a thin layer of of dark something coating the bottom. Didn't find any blockage or some kind of gunk to explain the issues I have been having. I checked the hoses that go to and from the heater and blew through one using lung power only and coolant flowed out the other hose with out any resistance. Put it back together and now the front heater works great, at least for now (rear still is cool).

Unfortunately, now I have a strong coolant smell about the time the thermostat opens. Can't imagine I'm that big of a blowhard that I could have damaged the core by lightly blowing through it. Maybe I dislodged some crud. Not sure but very frustrating. Too cold to be pulling a heater core.

Regarding the coolant warning sensor I originally asked about: The plug sticking out at the bottom of the reservoir is a dummy. It has been sealed at the factory. Apparently, GM still used the reservoir but not the sensor used earlier. I have found the same part number on other 2006 Yukon and Suburbans. So, I am still trying to figure out if there even is a low coolant sensor in a 2006.

Interested in what you find.

 

[2006Tahoe2WD]

I just changed the overflow tank on my 2006. I didn't see any wires or a plug for the sensor. I think the answer is no - there's no level sensor for this year/model.

 

[rockola1971]

Im with the other guy that mentioned the Tees and crimped on fitting at the heater hose where they attach at the heater core. I had the same problem on my 2005 Denali. Those Tees were horrible to get off the heater core nipples. Do yourself a favor and replace them now. The crimped/molded plastic fitting on the heater hose coming from the water pump will break. The plastic fitting gets very brittle from the cycling of hot/cold around the engine. Dorman makes a replacement that you just cut the old molded/crimped fitting off the hose and the replacement is barbed if I remember right. Sure sounds like you are getting alot of air trapped in your cooling system and those tees will do that. Didnt take much to burp my Denali when I did all that work. But it did need to be burped.