Will Radiator Stop Leak Work for the Heater Core?
 

Help! My '78 Daily Driver is having a couple of problems. Latest is anti-freeze on passenger side carpet. I know probably heater core. 2 week ago I dropped the car off at my local mechanic for an oil change and he told me the hose going to the heater needed replacement. The bracket had fallen and the hose was suffering from a case of road rash. Being it was there and he had it up on the lift I had him replace. Shortly after I noticed small amount of steam on windshield by defroster vents and now the anti-freeze wet carpet. Could it possibly be, hopefully be just a not tight enough connected hose? I have replaced heater core before in a '81 El Camino and it took about ten minutes. I know our cars are a bit more challenging so I'm hoping to avoid having to replace until I can make the time.

Thanx,
-Pete. :steering: KEEP DRIVING!!!

Heater cores tend to leak where the metal pipes enter the core itself. The stress of changing hoses probably did it in. Stop Leak may work; doesn't hurt to try. 4 to 8 hours is a pretty good estimate to change the heater core if you have a/c--I've done it twice in C3's.

don't use stop leak you wont be happy and will have to fix it anyway later....

:iagree:

I don't know that I've ever had it solve a problem for me.

Is it true that the dash needs to come out to change heater core?

:iagree: Chances are it will plug up the heater core so antifreeze won't circulate through anymore. You're better off either bypassing the heater core or replacing it.

Being in NJ I think I'm going to need the heat sooner or later. Where do the hoses connect to the heater core? Underneath? Maybe I'll do a bypass to hold over temporarily until I can fix right......

i think it depends on if you have AC or not, what yr is the car?

Man, same thing here... I haven't had my heater hooked up for the last two years as I never use it because I don't drive the car in the cold, but this fall I wanted to do some more driving so I hooked it back up. It was fine when I disconnected it, and it was fine for the first 30 miles, but then I started to smell antifreeze, and sure enough, right on the carpet.... I will be pulling the box apart this week, mine is an AC car.

I used Alumaseal (spellin?) on a Blazer that was steaming the windsheld. Stopped the leak till I sold it 6 months later.

Three solutions..1.by-pass heater core....2..use Bars Leak and it should stop leak...3..replace heater core...
I have had good success with Bars Leak till I decided what to do....

Bars Leak will probably work. It's worth a try. I have a radiator buddy that gives a can of Bars Leak with every radiator he sells. Larry

Be sure to put it directly into radiator,not the overflow tank...

Just a word of advice regarding radiator seal and Bar's-Leak in particular. This stuff will tend to collect/settle in the water jacket and can block water flow around the cylinders.

I removed the engine from my '63 Corvette to rebuild it (I'm the 2nd owner) in 1970. When I disassembled the engine I discovered that the original owner had dealt with a leak in the aluminum radiator by dumping Bars-Leak into it. The water jacket; from the top at the back of the block, diagonally, to the bottom at the front, was solid Bar's-Leak on both sides of the engine. With this much restricted water flow, there is no way the engine could be cooled properly. It would probably explain why the rings appeared "cooked" in under 25k miles. I spent a couple of hours with a welding-rod cleaning that stuff from the water jacket, it was packed solid.

I agree with those that suggest by-passing the heater core if you must use the car, but I would replace it before I would use any stop leak.

GUSTO

:iagree:

:iagree: dont use it. do the job right the first time dude! your vette deservse it

:iagree:

I've learned two things NOT to do to cars... no silicone based interior products and NO engine additives. Previous owner used both... plugged radiator and who knows how much of the engine coolant passages. Bypass that puppy.

Mine gets hot enough through the floor/firewall anyways to keep me warm down to 45 degrees or so.

What's the best way to bypass? Simply disconnect the 2 hoses to the heater core and connect them together somehow? One of my summer projects was supposed to be putting a shutoff in the hose to keep the car cooler but my typical procrastination kept me from that. Sure wish I had done it now. I could simply shut it off until I fix....

Yes, disconnect both hoses from heater core and connect the two together ... forming a loop from water pump to intake manifold. Note: some folks have their shutoff valve in the return side from core to intake ... but ... that doesn't address the higher-pressure hose from pump to core. Although one is a feed & one is a return ... even the return hose will have some pressure in it ... particularly when hot and engine off. To truly isolate the core ... either take it out of the loop by connecting the hoses as you suggested ... or install 2 shutoff valves ... one in feed & one in return. In a "pinch" I did use visegrip pliers for a SHORT term, only-to-get-me-home bubbafix.

I just put some Bars leak in one of my DD's. Been using it since my Dad's day. Will drain it out in a month if time (weather)permits or later in the spring. Works everytime and didn't effect the heat output.