Heater tube

[stretchmma1983]

My 2002 is leaking coolant from what I thought was the thermostat housing. I know see it isn't and have been told it could be a heater tube underneath the manifold. Has anyone had this issue. It loses water but you can never see it.

 

[DILLARD000]

Welcome to the Herd.! Lots of friendly knowledgable folk in these forums.

Factory & Aftermarket junk Plastic ThermoStatHousings on V6~4.0L~SOHC are NotoriousFailureItems;
sooner\later they crack+leak along lower plastic body seam into engine valley under IntakeManifold.
Engine heat cooks this into a grimey coolant swamp; at first only producing a bad sweet smell,
as leak worsens it drips off engine backside over TrannyBellHousing to the ground.
Best fix is to upgrade from junk Plastic TStatHousing to an Aluminum TStatHousing.
Using a good FlashLight or ShopLight, inspect TStatHousing under ThrottleBody;
peek under IntakeManifold; odds are you'll see signs of leaking coolant; no "Heater Tube" as you call it.
Click here for details on replacing+upgrading the ThermoStatHousing.
Consider renewing Fan+Clutch+Pump+Belt+Hoses, upgrading PlasticRadiator+PlasticHeaterValve,
& also renewing TimingTensioners while TStatHousing is out of the way; click here for info.

 

[Todd Z]

As said, There isn't a heater tube under the manifold, Also the coolant doesn't run through the manifold either to leak. More then likely the t stat housing.
Look as said and you will see the housing is more then likely the issue.
I sell the aluminum replacements if you need one.