Possible heater core leak

Hi all. Just noticed a small leak on passenger side floor mat on my 2003 Tundra . Just bought a month ago and have put 600 miles on it and just now seen the leak. Does anyone know if the radiator stop leak additives work on heater core leaks ? Do the additives do harm to cooling /heating system ?

 

Yes, stop leak additives are bad for the cooling system and don't work. Do not use them.

 

Are you sure it's not just water? Has it been raining in your area? A leak in that location is not uncommon. It's leaking from the cowl area around the windshield wiper.

he's got a picture of it in post #5.

https://www.tundras.com/threads/the...vestment-‘build’-a-chronological-story.46816/

 

Do I assume correctly you already know it's coolant and not water leak from outside ?

 

Its most likely your clips that hold your cowl in place that have failed/old rubber gaskets.

There is one directly over the blower motor and it drips straight down and rolls around and out of the motor casing onto the pass side floor mat.

Caulk up those clips. Make sure you caulk all around the clip and down into the screw threads. I didn’t caulk the screw hole the first time (in pics) and ended up still having a slight leak. Ended up Gorilla Arming a handful of caulk up the blower hole onto the backside of the clip to finally resolve the problem.

There are many other weak points for leaks which you can find on my build page above that @FirstGenVol provided.

 

Thanks everyone for your input. It has been raining here a lot. When I saw the leak I just feared the worst cause ( heater core) . I’m going to keep an eye on coolant and hope that leak was just from all the rain. Thanks again

 

Think before using that stop leak for a moment...No, don't use it. It also coats all water passageways throughout the motor, radiator, etc.
Like clogging your veins with good ole deep southern fried foods and other good stuff like a thin or thick slice o butter on crackers with your soup.

 

Hang out around here for a while and we’ll get your Tundra in top shape.

Sounds like the rain is leaking in like we suspected based on your input. The other area for leaks is the back window slider track.

 

Careful, they'll also get ya to wearing gloves during head breaks between mechanikin on the trk.