Heater core leaking?

[Pa Goose]

Been noticing a smell of antifreeze inside the car lately and have to fill the rediator about every 4 or 5 days. I suspect the heater core is leaking and am thinking about replacing it. The last heater core I replaced was a nightmare on my 74 F250 4X4. Where exactly is it and how difficult is it to replace?

[bill81vette]

do a search...there was a thread as while back on it,
seems to me it wasn't easy....sorry...

[gmjunkie]

Originally Posted by bill81vette

do a search...there was a thread as while back on it,
seems to me it wasn't easy....sorry...

Yeah,they put the heater core on the Assembly line and then built the car around it!!I'd rather pull my own teeth with Vice Grips!! A/C Evaporator ain't No pick-nick either, and I'd rather do 2 of them than a heater core!!!

[Guy]

I few years ago I found the passenger side carpet on one of my 82's wet. Sure enough it was the heater core. That was the best $350 I've spent in a long time.


Guy

[6880 Mike]

AIM and GM Service Manual will be a big help. Replacing the heater core is a PITA for AC cars.

[Red Dogs]

All good advice, I found an old thread that was really helpful, step by step with wrench sizes and all, the worst part is getting the heater box back into place,it is really tight in there as you can imagine, I did it over a couple of days( also did new belts, hoses, water pump, radiator,clamps, etc., don't plan on doing it again!!) it takes patience and a cool head, have your old core rebuilt as the replacements don't fit worth a **it, the tubes don't line up or fit the heater box and I refused to Bubba up my box, cost me a little more to have mine redone compared to an aftermarket one but it fits the way it should, if you can't find anyone in your area to do it let me know and I can tell you where I had mine done. It isn't a pretty sight to see a 275 pound old man curled up under the dash of one of these cars !!

[chevy6673]

Originally Posted by Pa Goose

Been noticing a smell of antifreeze inside the car lately and have to fill the rediator about every 4 or 5 days. I suspect the heater core is leaking and am thinking about replacing it. The last heater core I replaced was a nightmare on my 74 F250 4X4. Where exactly is it and how difficult is it to replace?

am replacing just the heater hoses and its a big pain so i bet the core would be a bigger nightmare i cant get a screw driver on the claps am trying little wrenches..looks like hose is melted to the core??? any tips

[Wayne robson]

Its worth trying this, a few years ago i did this on a old buick electra.and it worked.disconnect both heater hoses and bung them at the water pump to save your anti freeze , get a couple of wine bottle corks or rubber bungs,have them ready, go buy a bottle of radiata stop leak, the one i used years ago was bars leak, i dont even know if its still available,get a watering can or a hose going from your hot water supply, fill with very hot water and poor it into one hose into your heater core let it run untill it comes out the other hose,this is to heat up the whole core, then finally bung up one of the hoses and add the stop leak whole bottle, then add the very hot water until the whole system is full then bung that end and leave it for aprox 3 to 4 hours,after that remove the bungs flush it out again with hot water , and re connect the hoses, add water as required,. i personally would not use this in the whole radiator system as it can restrict the flow, but in heater core not such a problem. regards wayne.

[wallyknoch]

I sold a product made by Solder Seal, {Liquid wrench/Gunk} called 'Block Sealer" it really works, Dump that in before you tear the car apart. Might just save a horrible job. ie. replacing the core...

[Red Dogs]

Originally Posted by chevy6675

am replacing just the heater hoses and its a big pain so i bet the core would be a bigger nightmare i cant get a screw driver on the claps am trying little wrenches..looks like hose is melted to the core??? any tips

Try removing clamps with 1/4 in . drive sockets, they're in tight spots but can be done with patience, after you get them off cut the hose carefully lengthwise at the core to split them, don't try to twist them off without cutting them or you might loosen up the tubes where they solder into the core, if you do you will have to remove the core to get them soldered back in.
Also I would cut one of the hoses off near the core to let the coolant drain so you don't get a facefull when you are under there trying to get the hose free from the core !!

[jdp6000]

The only way I was able to get the hoses off was by cutting them tight to the core fitting with an exacto knife. Remove the clamps. then cut off the remaining hose on the fitting. if you are replacing the hoses no big deal. if your intend on reusing the original hoses you loss about an inch and a half.

If replacing the core do the same thing cut them like stated above. Core replacement is time consuming but not hard. Only trick is to remember te one bolt on the firewall... engine side.

Jim

[Evolution1980]

Pa Goose (John), you've already gotten good advice above. Yes, it's a major P.I.T.A.

If it's leaking, get it fixed soon. It often leaks into your passenger side floorboard, soaks the carpet and makes it sticky, as well as when you use your defroster, it'll fog up the window with a nasty film.

[jdp6000]

Originally Posted by chevy6675

am replacing just the heater hoses and its a big pain so i bet the core would be a bigger nightmare i cant get a screw driver on the claps am trying little wrenches..looks like hose is melted to the core??? any tips

Cut them off at the bottom of the core. then cut away at the rubber. Its going to take some time. If you get enough cut away you may be able to use snipes to cut the clamps. Or do you have a dremmel?

Jim

[chevy6673]

Originally Posted by jdp6000

Cut them off at the bottom of the core. then cut away at the rubber. Its going to take some time. If you get enough cut away you may be able to use snipes to cut the clamps. Or do you have a dremmel?

Jim

thanks ,yes this is how i will do it on monday after work...

[LVMYVT76]

Make sure you put back on the special molded hoses, if not they might kink at the bend when they get hot.