BigRed82

My car's blowing cold air when the heat is on. The heater core hasn't leaked into the floorboard like it's supposed to when it fails. Can it fail and not leak or do I probably have a blockage of coolant going to it?

Yesterday on the interstate the car started overheating, I pulled over and checked it out and the Heater Hose connecing to the water pump was leaking. I was running the A/C, not the heat though. So I got a friend to take me to parts places, none of them had the specific type of hose which is 3/4" on one end and 5/8" on the other. SO -- we just got some cut-to-fit 5/8" and just figured it would be kind of tight on the 3/4" end. Seems to have worked. I still have no heat and I'm afraid of driving 300 miles home with the wrong hose.

So, any ideas on how to fix the heat and should I replace the make-shift heater hose (5/8") or will it work??? I'm not very experienced with working the heater core... or virtually anything on that side of the firewall. I've replaced the water pump and radiator recently to get it to stop overheating and they're working great, but now I have no heat. So any help would be very very very much appreciated!

HBHRacing

flush the heater core.

crasher88

x2

I say your heater core is cloged. Do you use tap water or distiled water in your cooling system? A 95 f-body should still be using regualr green antifreez so you don't have to deal with dexcool and its nightmares that it brings. I say flush your heater core and if you have an air compressor try blowing it out with some air. Also while you have the hoses disconnected flush the heater hoses they might be cloged as well.

BigRed82

So... should I take it to a GM dealership and get them to flush the heater core.. or some other garage or does it take less than an hour and I can do it myself?

I've never heard of flushing a heater core so I'm not sure how to do that.

crasher88

real simple. Just disconnect the heater hoses from the water pump and take a water hose to each one of them until they flow freely. I'm sure all thats wrong is that you have some rust build up either in the core, hoses, or both. If you can try and take the hoses off from the heater core its self and flush the hoses and core seperatly. This will also help you determin if you hve to replace the heater hoses or core.

BigRed82

Before I replaced the radiator and water pump, my old radiator was SEVERELY rusted. I flushed it a few times but eventually had to just replace it.

So, I think you're right, it's extremely probable that the heater core is clogged with rust, but does that mean a flush will fix it? Or do I need to replace it regardless???

crasher88

I'm sure you can salvage it with just a good flush. Worst case senario is that you will have to replace the heater core. Not extreamly difficult on our cars takes probly about 3 maybe 4 hours depending on the tools you have, knowldge, and difficulty you will encounter while trying to disconnect things. The hardest part is getting the hoses off the heater core pipes. While your flushing the core you might as well flush the block and radiator and when you go to fill it back up use distilled water. It will help cut down on the rust formation in the cooling system.

HBHRacing

flush, refill system with water. Heat the car up and then repeat several times. Then finaly refill with 50/50 mix of antifreeze and DISTILLED water.

SCMedic

Anyone have a How To: on replacing the heater core...I'm tackling this this weekend.

sick94

^ yeah what he said cuz I got no heat! makes for a cold drive to and from work .

crasher88

drain coolant, undo heater hoses that connect to the heater core at the fire wall, unbolt small clamp that hold heater core pipes to fire wall. Go inside remove glovebox, find a black cover with 4 lil bolts hold it on. Remove cover and fung she the core out, reverse process to install refillt and check for leaks. The hardest parts is taking the hoses off the heater core to begin with since there is little room to work with and the hoses are more than liekly extreamly stuck on the pipes since they are old and probably have never been removed. Also be careful when you install the new core since if you damage it enought to make it leak then you will be oding this all over again. Took me about 3 or 4 hourse from start to finish.

sick94

well it doesn't sound to bad. i've already unhooked the hoses from the heater core so i could bypass it to drive. I thought you'd have to pull the whole dash down but if its thats close i'll do it myself. the local dealer ship quoted me $390 to replace it and i told them to suck it lol.