Ruptured Heater Core?

[SirFoxx]

Hello--

A few months ago, right before it got cold, I had the joy of replacing the heater core in my '86 TC. All was well until a few days ago. I was cruising down the road at ~45mph when the sudden smell of coolant hit me, along with white smoke coming out of the rear of the car. Pulled over, looked under the car, and coolant was pouring out from under the evap box. Opened the hood, and everything surrounding the heater core tubes was soaked. Upon further inspection, I saw a line had blown off the heater core (the left hose to be exact). I got the hose back on, tightened down, and carried on. However, since then, there has been an all too familiar smell in my car when the hvac system is running......coolant. I thought that maybe some had gotten into the system from when the line blew off and sprayed everywhere, and needed time to dry up. That is not the case.

At the gas station today (2 days later), I pulled the radiator cap off, and I couldnt see anything in the radiator. Bought a gallon of water from the station, and it took about 3/4 gallons to fill up the radiator again. A bit concerning if you ask me.

Questions:

What could cause the heater core line to blow off, and to rupture the heater core itself?
If all the coolant was leaking out of the heater core, where does it drain to?
Could a blown head gasket cause this to happen?
What are some signs of a partially blown head gasket to look out for?

I bypassed the heater core when I got home, so I will watch the levels the next two days to see if it is the same, or if I am still losing coolant somewhere. My oil is still fine, and the exhaust isn't steamy. The only thing I noticed was the coolant after I drove home was a bit frothy at the top, but I would like to think that was from all the air that was in the system. I didn't notice the coolant bubbling while the engine was running, so hopefully it isn't a head gasket. Fingers crossed!

edit: I just thought about it, I never checked my fluid level after the line blew off. Maybe I'm not losing coolant....I guess I will report back about that in a few days.

[gadget73]

Bad radiator cap that caused the cooling system to over-pressure is a fair guess.

Core basically drains inside the car. See if the padding under the carpet is soaked.

Bad head gasket could, but honestly its not the most common thing on the 302. Not impossible, but I'd be looking at simple things first. if the coolant has a distinctly scummy look, that might be head gasket. If its bad enough to blow the core up, just running it at idle with the cap off will tell the tale. It will bubble very obviously and smell like exhaust coming out of the cap if there is a problem.

[nfldfordltd]

Likely you have a big airlock in the cooling system after that. Plus I wouldn't rule out the heater box still being full of coolant after the line popped off and the heater core is likely still draining into it as well.
Fill, bleed and keep an eye on it. Excess coolant pressure is something I fought with on my 88 Town Car for years. Tried several different rad caps, they were all 16 psi Motorcraft parts, both new and used. The fix came in the form of an AC Delco 15 psi cap. Not a hitch since, about 4 years ago.
Good luck with it. Mine had me tearing my hair out. It would randomly blow brand new heater hoses, ate heater cores for fun, and even popped the block heater. That drained the coolant completely, it got very, very hot and that now why I'm replacing the engine six years later.

[Tiggie]

If the carpet is not damp, I'd say you have some residual stuff from the hose blowing off and a little bit coming inside the HVAC box as mentioned above.

I run a 7psi cap on all my stuff that fits one. RS-9 Motorcraft. I don't intend on very baking my engine past 245 Fahrenheit so no boil overs to worry about. Never had any trouble and the 88 had been 235 running before. Can't find one for my Ranger (uses a baby cap) but managed to find a 13-lb spec'd for a 1991 Probe.