Leaking coolant and pooling in passenger foot well

It sounds like the new heater core is leaking, it happens :-(

or- the drain is plugged for the AC system because condensate or coolant should be leaking onto the ground, not inside on the floor. Did you flush the cooling system last time to get all the old stuff out? If not, and it's old, it has turned acidic and will keep on corroding metal parts.

You can check that with a digital voltmeter at the radiator. That is a real big problem on GM vehicles but it can happen on any car.

Head gasket is bad. Any major overheating before the heater core
went the "first" time?

Broken plastic water pump impellers are common causes for overheating.

Thomas

It's not overheating. It's dripping onto the floor.

I know! Read my reply again. I asked if there WAS an overheating incident that caused the heater core to go the FIRST time.

This SECOND time could be due to a PRIOR overheating condition.

Thomas

I had to ask about "Prior" overheating. Sorry.

- Disconnect the plastic couplings from the 2 pipes that go to the
heater core in the engine bay
- remove the 2 angled plastic fittings from the the now disconnected hoses.
- Connect the two hoses using a suitable fitting (curved pipe)
- Run the engine until fully warmed up
- Check pressure of cooling system, check for exhaust gases in cooling
system by getting an air sample from the coolant reservoir bottle.

If all checks out fine, faulty heater core. If exhaust gases
are present, head gasket.

Thomas

You can also do a leakdown test of all cylinders, one at a time at TDC.

If coolant level rises or air bubbles are present, then air is
getting past the head gasket.

Thomas

Have you tried looking for the leak while doing a cooling system pressure test? Logic would dictate the hose connections are not leaking since you didn't have a problem for five months but that doesn't mean one couldn't have rattled loose. That would make more sense than a bad heater core. On the other hand, as one corporate trainer used to tell us, "we not only sell you parts, we sell them to you pre-broken", meaning new parts can be defective. The most likely suspect there would be a leaking crimped-on tank on the heater core. What you might consider in that case is to add a small bottle of dark purple dye to the coolant just before you pull the heater core out again, warm the engine up once first, then drain the coolant right away and take things apart. By the time you get the heater core out any dye will hopefully be dried in the area of the leak so you can figure out the exact cause. The dye will show up as a bright yellow stain under a black light.

I wasn't referring to flushing and refilling the AC refrigerant. It's the antifreeze / coolant that becomes acidic from the normal combustion gases that seep into it. The corrosion inhibitors and other additives in antifreeze wear out in about two years; that's why we replace it.

To test the coolant, use an inexpensive digital voltmeter. Place one probe on ground, (battery negative post, or any paint-free body surface), then touch the other probe in the coolant. The higher the voltage reading the more acid there is in the coolant. That acid is in contact with aluminum, cast iron, brass, lead, and tin. Any two different metals and an acid is a cell of a battery. That results in "galvanic action" which is a fancy name for corrosion and will eat through a new heater core real fast. THAT is the common problem I was referring to with GM trucks. The symptom on those is the new heater core only lasts about a year.

If you want to be safe and you have to replace the heater core again, flush the cooling system with water from a garden hose first, then replace the heater core and refill the system with new antifreeze.

YEP DOC, I'VE HAD MY HEATER CORE HOSE CONNECTIONS MYSTERIOUSLY GET LOOSE AND LEAK BEFORE---AND SEEP INTO MY FLOORBOARD, BEFORE IT WENT INTO THE HEATER BOX

I'VE BEEN WORKING P/T AT A PARTS STORE.I SEE STUFF BEING RETURNED IMMEDIATELY AFTER IT WAS INSTALLED (JUST DEFECTIVE FROM THE GET GO)

LACK OF ATTENTION DURING INSTALLATION AND ALLOWING IT TO MOVE AROUND IN THE CASE WITHOUT "PADDING" (COULDA BEEN THE INITIAL PROBLEM)---MAY HAVE ALLOWED IT TO RUB A HOLE IN IT

I'VE HAD PROBLEMS ALONG THE WAY--WITH MY 6 CJ 5s AND 1 WILLYS JEEPS

PIC

1) HERE'S WHAT I DISCOVERED THE 1ST TIME I PULLED MY DASH AND HEATER (THIS IS MY #6 JEEP). THIS SCREW WAS SCREWED AGAINST THE CORE----IT FINALLY STARTED LEAKING AFTER YEARS OF EXPANSION AND CONTRACTION.I AIMED IT SLIGHTLY THE OTHER WAY. IT'S CLOSE, BUT NOT TOUCHING!

2) ON THIS MY PRESENT 1977 CJ 5, I'VE HAD IT SINCE THE EARLY '90s, I'M ALWAYS TRYING TO IMPROVE ON IT. I INSTALLED A "BETTER" HEATER OUT OF AN '82. WHILE I HAD IT OUT. I MODIFIED THE BACK OF THE HEATER, THEN TRANSFERRED MEASUREMENTS TO THE FIREWALL. THIS TOOK A COUPLE OF WEEKS FOR THE WHOLE PROCESS. I MADE "ACCESS PORTS" IN THE FIREWALL. NOW I REMOVE THE BATTERY TRAY AND I AM ABLE TO GET TO THE FAN AND THE CORE, WITHOUT RIPPING OUT THE DASH AND HEATER UNIT. IN THIS PIC, YOU CAN SEE A "IN A HURRY" MESS UP. SEE THE LEAK ON MY PANEL. SHARP EDGE GOT IT!

3) PULLING IT FOR THE FIX

4) FIXED W/ TORCH AND SOLDER

5) INSURANCE--ADDED RUBBER HOSE OVER THE TUBES TO PREVENT RUBBING

6) BENT MY OLD COVER TO GET THE SHARP EDGE FURTHER AWAY. MADE THINGS LOOK BETTER WHILE I WAS AT IT, AFTER ALL I WAS IN A HURRY THE 1ST TIME I DID THIS

7) BATTERY TRAY AND BATTERY BACK IN PLACE."MR. JEEP" IS READY FOR ANOTHER 35 YEARS OF SERVICE. THEN I HAD TO CLEAN HIS BROTHER, "WILLY", OFF/OUT (I AM NOT A HOARDER!) "WILLY" IS 66 YEARS YOUNG

. AND YOU'RE WONDERING WHAT THE HECK DOES MY JEEP HAVE TO DO WITH YOUR SITUATION?

. WELL ASIDE FROM MINE BABIES LASTING FOREVER,

I WANTED TO BRING IT TO WHOEVER'S ATTENTION. WHERE IS THE HOLE. WHY IS IT THERE. HOW DID IT GET THERE. HOW CAN WE MAKE THINGS BETTER. MAYBE 5 MINUTES OF INVESTIGATION MIGHT BE BETTER THAN SLINGIN' THE "OLE LEAKER" IN THE TRASH, REMOVING THE NEW ONE FROM THE BOX, AND CRAMMING ANOTHER ONE IN, ALL IN A 30 SECOND SPAN OF TIME. BACK WHERE YOU WERE MONTHS AGO!

THE MEDIC

Thanks for the info. Vwscott but no coolant is lifetime. GM advertised Dex-Cool as lifetime, but then after you buy the car you find they say to replace it every three years. It has turned into "Dex-Mud" by then. Even the Dex-Cool manufacturer doesn't promote three years; they say replace it every two just like all other coolants. It doesn't matter what the coolant is made from or what's in it or not in it; it's the additives that wear out and the acids that form. That's why it must be replaced periodically.