Help!! Weird Heater Core Problem!!

[IBChillin32182]

Over the past three years I have had to replace the heater core each year about this time every year. Mine went out again today. What could be causing me to keep blowing them. I put new antifreeze/distilled water mix in each time. I've used three different heater cores and none have lasted any longer than the other. I have used a generic one from some no name auto parts store, a napa one, and a heavy duty one from 5.0 restoration. Any suggestions????

 

[sgarlic]

2 things come to mind..

1) Did you use a flexible sealant when you seal the new core in to the blower housing? If you use something hard, when the core expands it'll crack it.

2) Are you using the restrictor that goes in the hose? Ford added it later on to the inlet hose since the heater core can't handle the amount of coolant coming in to it. If not, definately get the restrictor.

 

[Daggar]

...and third. Purchase a core from Ford this time.

 

[z28kla]

I've had this same problem and it was because I didnt use a restrictor.Fords is brass with a rubber insert and they almost allways are bad. I built one out of a brass 3/8 barb to 1/4" pipe fitting. You have to cut the barbed end off and drill the hole out to 3/8-7/16 ond install in the feed tube coming from the water pump. Put it in the rubber hose right before the heater core tube. It has worked flawless for 2 years now...and its an auto zoner! I deffinitley think O.E. core would be better though!

 

[IBChillin32182]

Ok I'll try the Ford one this time with z28kla's restrictor... I have used a restrictor on one of them and it still blew, but that was the one from the local no name parts store. Hopefully this will fix my problem because I'm really getting tired of having to replace these stupid things.

 

[90mustangGT]

Some good sugestions on this thread.

Also, be sure the return line isn't the one your putting the restrictor in and be sure that line free-flows, if it's clogged it will trap pressure.

What radiator cap are you running? I would get a 14lbs or lower unit.

 

[bubba-dough]

Just to re-interate what others have said: Make sure you get all the old sealant out of the box and put new flexible sealant in to hold the core. Definately buy a good heater core and not some cheap knock-off discount parts store part.