billschroeder5842

In the end, it is death, taxes and heater cores.

I've replace two so far. My 82 had it go at 112k and the 89 had it go at 72k. The 82 took about 8 hours and the 89 about 10hours.

Now, I'm all freaking on my '91 ZR1 as the "new style" interior is a royal PITA to replace. The 91 has 74k and I'm afraid it is a ticking bomb. I've had no issues, but these cores break with zero warning.

From those of us who are "lucky" enough to have their heater core go, how many miles were on the car?

383vett

Can't remember when my 84's core went. It was decades ago and my memory has blocked all access to that horrible ordeal.

vader86

None of mine have gone, the 86 went 175K and this 88 is at 130K.

I swap out the coolant every 2-3 years to get anything corrosive out of there.

ctmccloskey

I would have to agree with VADER on this one. If the fluid never gets acidic then there should never be a problem. I do them every 3 years and replace the a/f and distilled water. Unfortunately I bought my C4 used and who knows if it was ever changed before that.

Flushing your Brake Fluid every 4-5 years will save you even more headaches!

NavAir

My '89 still has the original core, 72K miles. I do change the coolant (fairly) regularly. That said, I won't be surprised when it goes...

Steve

New Machines

My ’87 went out at about 55K. I replaced it about 2 years ago. I documented the process with a write-up and photo’s. If you want a copy of this procedure, send a request to
cesmachines@yahoo.com. I’ll be happy to send it to you.

Bill C.

pcolt94

Me to (knock on wood).

When I got the car in 04 it had poor heat till I flushed the core. Found out it would get bad again in about 2 years so I try to flush the core every year and a complete flush 2-3 years also. I don’t think the car was taken care of very well technically (from signs I saw) even though it looked pretty good. I'm at 176000 miles now.

1984Z51auto

My 1984 went 100k miles without a heater core issue. Water pumps were a different story but, I did do a fluid change every couple of years (or when the pump seal failed). The 1996 is still good at 22 years old (hope this doesn't jinx it!).

Mr. Peabody

My 95 heater core went out at about 80,000 miles.

phrogs

I have a ZR-1 heater core from a 90 or 91 Z if you want one as a spare.

JrRifleCoach

I've got a NIB core (make offer)(include shipping)

My theory for early models is the heater control valve closes off water flow to the heater core during the warm weather months. So the heater core water sits stagnant most of the time. A ticking time b0m8 waiting for the most opportune moment to leak. My fix was to pin the valve open to keep fresh water flowing. (Got a new valve too)

84 4+3

The one in my 84 was dead when we got the car. After 14 hours crammed in that footwell I did it. I barely fit then and certainly won't be able to now. I did everything from the bottom as in I didn't pull the dash pad... the two top screws on the box were left out on purpose. I was 17 at the time and young and dumb. Now I'm just dumb. My clutch master and slave took a dump 24 hours after I fixed that too. Been good for almost 5 years now. I turn the heat on every couple of months just to make sure it circulates. Coolant change ever 3 years.

Tom400CFI

^This is it, folks. Maintain your coolant...don't change cores.

I haven't changed a heater core in one of my vehicles in over 20 years.

Also, I've been using the much maligned Dexcool for 20+ years. Hmmmm.....


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vader86

I also turn on the heater intermittently throughout the rest of the year to cycle out anything sitting in the core.