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: Car cranking, but then dying

From my experience, checking the fuel filter and spark plugs is a great place to start when trying to determine why your VW beetle is sputtering and stalling out. The symptoms you describe however sound like your Volkswagen is experiencing...

Q: I was backing out of my driveway and heard a loud clunk coming from the rear end of my Ford f250 1979

Hi There, It sounds like you may have a bad universal joint (U-Joint) that may have too much play in it. When this happens, as the torque of the transmission transfers the power to the rear end, a loose U-joint...

Q: Oil leak on a 1996 Dodge Neon

Watch my video "finding and fixing car oil leaks" and find another mechanic. In that video, I show how to put ultra-violet dye into the engine and then run it. The green dye fluorescents where the leak is. You...

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...
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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...