ballzoutstang875.0

I have an 87 5.0 LX and I replaced the heater core about a month ago. I have run it every day with the chilly mornings in Ral. N.C. Everything had been fine until a couple of days ago, sure enough, green antifreeze was slowly dripping from my passenger side floorboard. Its done this before and I had already located were it was coming from. It just doesnt make sense that this BRAND NEW heater core would already be shot. I was thinking that maybe I stressed the brass necks while putting the old, stock hoses on. maybe the welds broke or something??But, its just now started, that cant be the problem?? The temp gage will climb and fall constantly but wont peg, "luckly". I will turn the heat on and when heat does work and get hot, temp will drop to about half way (normal). When heat is on but not working(cold) temp will climb to about 210-240 then all of a sudden, heat will turn hot and cool the engine down. ??????
could it be something else? When we put this current heater core on, I had to cut the hoses- both of them- to get them off. I found out that they were still long enough to work when the new one was on. could it be a clogged or kinked hose?? Thermostat?? Heater Core?? REMEMBER: Antifreeze is dripping on pass. floorboard. I asked my dad and he thought there was just too much pressure in radiator so I loosened the rad. cap for a few min's. and let it run. NO FIX. Please help me fix my stang!!!!

mdvaldosta

Sounds like you have two problems. Obviously if your leaking antifreeze on your floorboard then you've got heater core problems, but that in itself won't cause you to overheat unless you run low on antifreeze. Could be a thermostat, but not likely because it cools when you turn the heat on in the car - which also tells me theirs a good chance the water pump is pumping. So, sounds like a radiator problem. First thing I'd do is get some power flush stuff from a local parts store to clean out some of the old gunk, corrosion, and rust from your cooling system and see if that does it. To check the t-stat just feel for the top radiator hose getting hot and hard when the car is fully warm, that will let you know the tstat is working. Its hard to tell if a water pump is bad unless its leaking, same thing for the radiator.

ballzoutstang875.0

Well, I dont think its the Radiator because it is cooling the car once it gets to a certain point, as weird as that sounds.LOL Things still point to the Heater Core but its just not fair.
This means that I have to do the sh*t all over again. PAIN IN MY A$$. UHHHHHH guess id better get started on taking this dash apart!!! If "ANYTHING" comes to mind, PLEASE tell me. Thanks

Quote of the day: The words Mustang and Reliable dont mix too well!!
I still love her with all of my heart though!! LOL

91hatchgt

Check this out... When I got my stang, it was in PERFECT condition. Everything was just dandy. Until about a week went by and it started leaking anti freeze onto my driveway. So I checked it out. Down the side along each of the cooling strands in the radiator was a white dot. This is how the guy at the rad shop explained it to me.

" After 14 years, the radiator starts acting up, such as your teeth would after eating a lot of candy. Do you see those little white spots? Those are like cavities in your teeth. If I were to boil this radiator, it would probably fall apart in the boiler. If I were to try to drill out every cavity and fix it, it would cost more than just getting a new rad anyway. And you not having any cooling problems is a mistery to me."

Well I never had any cooling problems, just noticed a little coolant on the floor. Turns out my rad was about to fall apart! Thank god I found it. Only cost about 130$ for a stock replacement. Take a look at that. As for the coolant in your car, that's all about the heater core or hoses.

ballzoutstang875.0

wow, i've never heard of a Radiator literally about to fall apart. No, I havent payed attention to the radiator, but ill take a look. I dont think I have the org. rad. though. I am going to determine my problem this afternoon, Im just going to bypass the Heater Core and if my antifreeze leaking problem stops(which it will) and if the overheating issue goes away, then the Heater core was obviously junk. If no fix, i have another problem. Im putting my paycheck on it that the HC is the problem though. It just really aggervates me that a month after I installed the bear of a part( if you've dode it before, you know what I mean), the thing fails on me. UHHHH, by any chance, does anyone know what size bypass tube I need for my HC?

88GT40

i wouldnt use the old hoses on the heater core any way take the dash back apart and run the car with the heat on see if you can see where the leak is coming from i'ts prolly just from one of those old hoses you reused, chack and replace if neccessary, also to keep your temp in check i would flush the system with the radiator flush produst from the auto parts store and i would also replace the stock 190* therm with a high flow 180* therm, and if you want ot free up some extra horses along with cooling it dowm some more install an elctric fan with adjustabel thermastat"assuming you haven't already"