Leak on Underside of 2003 EnvoyXL

I have a slight leak just behind the passinger side real wheel well coming from what seems to be a rubber drip hose that extends down from the underside of the frame. The substance leaking is slightly red in color and oily and it drips to the ground for several minutes after every use. Does anyone know what the leaking fluid might be?

Welcome to AF, sounds like a vent tube for the transfer case, follow it back to it's source for the answer.

Welcome to AF, sounds like a vent tube for the transfer case, follow it back to it's source for the answer.

Thanks...after each use there is about a 4"diameter spot on the garage floor which seems like a lot for a drip hose. Is this something I should be concerned about? I can't really get to the hose very easily to follow it to its source...

There may be some foaming of the fluid in the transfer case, pushing it up and out of the drain tube. I'd check to see that the transfer case fluid level is correct...overfilling can cause foaming.

There may be some foaming of the fluid in the transfer case, pushing it up and out of the drain tube. I'd check to see that the transfer case fluid level is correct...overfilling can cause foaming.

Thanks, I'll check that...

What a coincidence. My 02 Envoy XL has a green leak in the same spot (near the right rear shock) and appeared to be coming from the lines leading to a rear heater coil of some kind. When I checked my coolant level, however, not only was it right up, the colour was red (like Dex-Cool I think).

So, I too wonder what it might be?

Dex-Cool has an orange color and there are no coolant lines that run to the rear of the truck. My best guess would be that the greenish fluid is coming from the shock absorber itself.

(CORRECTION)
For rear climate control systems, there is a separate heater core located at the rear of the vehicle, supplied by circulating coolant from the cooling system. There is a possibility that there is a small heater core leak allowing coolant to drain out of the heater core box. However, the fluid should be the same orange Dex-Cool. I'm still thinking the green fluid is from the shock absorber.

We didn't ask washind if he's the orig owner of that veh. Could be somebody lost the Dexcool back when (ruptured hose or whatever) and replaced it with green antifreeze. It's not recommended for GM's aluminum radiators. If that's what happened, I'd get that green antifreeze power-flushed right away, replace with Dexcool & water 50-50.

The mystery remains. In reflecting on the leak colour, it was actually yellow/ green, almost florescent - which lead me to believe it may have been AC freon. As I crawled around I discovered two things. The rear silencer or mufler had been replaced with a straight pipe leading me to think the vehilce might have been in a small accident. Second, one of the lines leading to the rear heater core looked like it had been spliced with a section of rubber hose. I tightened the clamps and and wait to see if that stopped the leak. Being a new owner, I am not fully aware of the back seat HVAC controls but know that my son has been recently adjusting things. I'll bet that you're spot on, in that someone previously put green antifreeze in the system that remained pooled at the rear until my son adjusted the controls. I will most certainly follow your advice to get the system flushed and refilled with Dex-cool (while the rear heater is on). I previously lost an intake manifold on a Park Avenue due to Dex-cool problems.

Thanks...Dave

Ps. The exhaust noise without the silencer is very sweet and doesn't appear to be any louder.

Sad to report the green leak was freon dye coming from one of the aluminum lines near the rear passenger tire. GM parts alone were estimated at $1,000. Needless to say, I'm going for a splice and hoping it'll work. If not, the kids will be warm cuz I'll decommission the rear A/C.

Thought so, sorry, but thanks for posting back.

I have the same leak on my 2005 Envoy XL and it is the Dexcool for sure. I just need to know how to repace the rear heater core or at least how to disconnect the lines going to the core.

Mike

Welcome to AF, please do not post in threads over 90 days old. I am closing this, start a new one.