Skip the auto shop - Our mechanics make house calls

Q: Coolant leak from a black box (HVAC box)?

asked by on

Hi my name is ray. I need advise on 78 mark 5. it has coolant leak between the black box(HVAC box)and the fire wall. I didn't open the box yet but it starts leak when I turn on the heater so I just guessing it is heater core or the piping concerned. I just want to stop the leak so I'm planning to by pass the piping. It will cause only no heater? If it is leaking form the heater core, It will solve the problem?

The most likely cause of your leak is the heater core inside of the car’s heater case. The leak will come out of the A/C’s drain. If you are going to bypass the heater core then I would recommend connecting the two hoses together or just running a new hose from one pipe to the other pipe on the engine. This will ensure the coolant circulates through the water pump and cooling system well. The heater core can be replaced at any time in the future. If you need some assistance with this, consider YourMechanic, as one of our mobile technicians can come to you to diagnose the coolant leak and help you install a new heater hose to ensure good coolant circulation.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Small Oil leak

When it comes to oil leaks you have to look for the highest point on the motor you see oil and start there. Oil will always leak and go down toward the bottom of the engine and drip there. You...

Q: Check engine on knocking engine milky cap but not in oil change loud knocking noise while driving and cold start up

Coolant leaks can be external or internal. If the coolant is leaking internally into the cylinders or crankcase, that will require a fairly significant repair. If the coolant is leaking externally, unless the leak is at the head gasket or...

Q: Stalling hard to start

Hi there: On an 86 Lincoln Town Car, this issue is most likely contributed to a dirty or clogged throttle body or fuel injectors (assuming it's the fuel injected edition); or another fuel system component. It could be an obstruction...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...