Mechanics

LEAKING COOLANT AND POOLING IN PASSENGER FOOT WELL

2000 Volkswagen Jetta • 135,000 miles

Changed heater core 5 months ago. Was misting through vents and fogging up inside. Problem solved but back to same issues 5 short months later.

Car is back to fogging. Up and leaking coolant and pooling in passenger foot well. Smell of coolant is bad. Dash pulled myself and heater core replaced 5 mo ago. Help
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Lascott32@aol.com
September 4, 2012.




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.

Caradiodoc
Sep 4, 2012.
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

Tiny
Exovcds
Sep 4, 2012.
It's not overheating. It's dripping onto the floor.

Caradiodoc
Sep 4, 2012.
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

Tiny
Exovcds
Sep 4, 2012.
Yes I am losing coolant again too. Exact same issue as last time. NO the car is not overheating, nor has it ever. Yes the air conditioning was flushed out last time this happened. After Heater core was replaced, I had it in the shop to have the air charged back up. Which is a bummer because now to change the heater core AGAIN, Ill have to drain A/C again. Im just at a loss. Coolant is leaking out onto garage floor and into passenger footwell, and through the vents, inside when a/c or defrost is on.

Tiny
Lascott32@aol.com
Sep 4, 2012.
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

Tiny
Exovcds
Sep 4, 2012.
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
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Tiny
Exovcds
Sep 4, 2012.
Already checked for rising of coolant and air bubbles, none.
I beleive it is the heater core, but I do not understand why this fix only worked for 5 months and back to same issues. Certainly dont wanna go through that time of pulling dash and replacing again and it work for only 5 months again. AND draining and filling a/c.

Tiny
Lascott32@aol.com
Sep 4, 2012.
And. Thanks for the advice.

Tiny
Lascott32@aol.com
Sep 4, 2012.
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.

Caradiodoc
Sep 4, 2012.

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