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Loosing coolant in Tahoe

2004 Tahoe with 225k, 2wd, rear air and heat. For several months, I’ve had to add a little coolant about every 6-8 weeks. Have never been able to find a leak. Thought coolant concentration Had just gotten to low so I flushed coolant this week end and replaced with GM Dexcool. Loosing coolant faster than ever now. All hoses and area I disconnected are bone dry. Using a small mirror, I see a small hose not connected to anything that’s located just below the A/C dryer. This hose is a constant drip. Doesn’t smell like coolant but could this be it and what is it? Thanks in advance.

AC systems, because they are cold, cause condensation from the atmosphere. that hose is probably for the condensate water.

Would this hose still drain if I had full heat on in the Tahoe?

If defroster was on yes.

Sounds like your heater hose(s) or the plastic connections are leaking

One of your heater hoses is a shaped hose, the other is a bulk hose.

As for the connections, they’re plastic tees, one black, one white

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The little hose is probably the drain for the AC, condensed humidity from the air drops out, normal condition. Check your oil cap for a chocolate milky deposit. That would be a sign of coolant getting into the engine through a head gasket leak.

Good idea as referenced above to immediately check the engine oil and the automatic transmission fluid to make sure the coolant isn’t going there. Coolant getting into either of those systems could do a lot of expensive damage if allowed for any length of time.

Not that replacing head gaskets will be cheap…

A mechanic I talked to a few years ago said he’d recommend replacing the engine to a customer with a lower mileage used engine rather than doing the head gaskets. He said the cost was similar and you got a 35,000 mile engine. These engines last a long time so low mileage units are really cheap in the salvage yards.

I agree with those that say that this small hose is just the drain for the AVC condenser.

As @SteveCBT & @GeorgeSanJose said, check the oil filler cap for signs that coolant is getting into the oil. That would be bad!!!


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and they get brittle after time. plastic here is a horrible idea, lol

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I’ve got a 2008 Yukon w/rear hvac in my bay right now

Both heater hose tees are leaking . . . right onto #8 ignition coil. Coolant level was about 1 gallon low