My car was suppose to go to the shop this week.

  • 1988 MAZDA MX6
  • 300,000 MILES
My car was suppose to go to the shop this week but the other day I noticed the passenger floor was quite wet. I thought it was from heavy raining that night but couldn't find a leak. I happened to be checking my engine fluids before driving and discovered the radiator was quite low which it never is. I added a quart of water, ran the car to warm it up and the heater control on high to warm inside. Later after running it for quite some time, shutting it off and then returning to it, in order to leave, I noticed the passenger floor and mat is literally standing in water. Apparently the heater core sprung quite the leak!
I have no way to tow the car to a shop and I know that a heater core can be bypassed but I physically can't do that, so I'm wondering--"If I refill my radiator, keep the heater control to off position and heater temp to cold with fan off, can I drive the car or will it leak water out thru the bad core anyway?
Do you
have the same problem?
Saturday, December 15th, 2012 AT 9:06 AM

1 Reply

It will leak anyway because of the pressure that builds up in the system. Running the heater on hot and at medium speed will make the heater core act as a small radiator. That will remove more heat and lower the system pressure. Highway driving will also help due to the air flow and cooling effect.

First of all, if the car came originally with air conditioning, there is a drain pan with a drain tube that is blocked. Look for a 4" right angle rubber hose hanging down on the passenger side of the firewall under the hood. Squeeze that tube to clear it. If nothing comes out, squeeze the wire ring that holds it on to remove it, then stick a pencil into the spout to dislodge whatever is blocking it.

Leave the radiator cap halfway off. The second catch will keep it in place but it won't seal so no pressure will build up in the cooling system. Very often sediment collects in the heater core and at first will block the corroded spot. With no pressure in the system, the coolant will not get pushed past that sediment so easily.
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Saturday, December 15th, 2012 AT 9:27 AM

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