Another coolant leak help thread!

[2011TXDenali]

Hey everyone, I'm hoping to get some help with diagnosing the coolant leak on my 2011 Denali. I noticed the coolant level was pretty low in the tank and filled it up. I went out for some lunch after and when I came back out to the truck, it looked like someone basically poured out a new bottle of coolant under the engine. It has been parked for over a week and it is still slowly leaking. It is coming from above the oil drain plug (photos below). I am hoping this is something I can fix myself as I don't really have the extra funds available after Christmas to take this in to get done. Any help is greatly appreciated. Thanks!

 

[Doubeleive]

Most likely the source is the passenger side heater hose/t's on the firewall
but.. could be other things, waterpump, hose, reservoir tank crack, radiator.

 

[2011TXDenali]

Most likely the source is the passenger side heater hose/t's on the firewall
but.. could be other things, waterpump, hose, reservoir tank crack, radiator.

Thanks for the tip! After going up a little bit further, it looks like it might be coming from this hose.

 

[Doubeleive]

Thanks for the tip! After going up a little bit further, it looks like it might be coming from this hose.

what hose? there is no hose pictured there, I see a spark plug jacket/cover and the exhaust
any hoses in that area are up top

 

[Doubeleive]

your leak is coming from above and dripping down, which is how you find it but now you have to look up top

 

[repairman54]

Check the T connections up on the firewall. T connection routes coolant back to the rear heater.
One of mine was leaking. Coolant drips down onto the valve cover then down the back of the engine.
GM T fitting only, aftermarket is crapola, found that out the not so easy way. I replaced my heater hoses also for a once and done. Rock auto had gm hoses but not the plastic T fittings.
My dealer had the T's in stock, that tells me it's common.

 

[2011TXDenali]

Check the T connections up on the firewall. T connection routes coolant back to the rear heater.
One of mine was leaking. Coolant drips down onto the valve cover then down the back of the engine.
GM T fitting only, aftermarket is crapola, found that out the not so easy way. I replaced my heater hoses also for a once and done. Rock auto had gm hoses but not the plastic T fittings.
My dealer had the T's in stock, that tells me it's common.

Thanks, after searching the engine, it looks like the T connectors are the source of the leak! I couldn't tell which one was leaking but probably safe to replace both. Which parts would I need?

 

[B-train]

Those 2 T connectors and the rubber hoses that go to your waterpump. Go to an online GM parts store and put in your VIN. Look under engine cooling and they should come up in an exploded diagram. Make sure to use some sort of lube when going back together so you don't roll or knick an o-ring.

 

[mattbta]

Don’t use Dorman parts unless you like doing the job multiple times and/or possibly getting stranded somewhere. OEM or Gruven if you wanna be fancy.