AaaRrgg!!!! Heater core!!!
 

Came out today to find a puddle of green under the car. The 2 year old NOS Harrison heater core is leaking!!! Coolant running down between the heater box & the firewall. Am going to bypass it till I get the time to pull it apart & see whats up!!

i thought you didn't need heat in arizona.

That sux.. are the clamps inside the box or outside?

In the winter after a storm front has gone over, it clears off & the temps can drop 30 degrees in one day. Lots of low 30's-40's here in the valley. BUT, I dont stay just in Phx during the winter. I do go up to the high country & have lots of drive time in the snow with this car.

Outside clamps.. Just ticks me off that the high dollar NOS is leaking. Once I get it out, will take it to the shop that built my radiator last year. Have it checked out/repaired/rebuilt. May not be the core. The hot water valve is inside of the heater box. That could be leaking also.

i didn't think it got that cold there, 30 f is like summer here.

Arizona can pull down the high & low temp for the continental US on the same day.
Lots of times it can be in the 70's in the Phoenix area & 200 miles away in the White Mountains it will be 30 below!!! Can go swimming in the back yard pool in the morning, drive north 2 hours & play in the snow till afternoon & drive back home & go swimming again.

My NOS heater core needed to have the inlet tube soldered.

Gary, I looked it over real good before installing it. Also put in a NOS water valve at the same time. Got to be one or the other. Either way the box has to come out. Need to get it done before it really cools off.

Bringing this back up!!! After getting my core repaired last winter, there have been no issues,,,,till this morning!!! Very cold today, in the mid to low 20's!! Left early to have breakfast with some club friends. Driving down the road & glanced in the mirror. Saw a big spiral of smoke behind me!!! Quickly pulled over to check things out. Motor was running fine. Looked under the hood to find coolant running down again all over the hot exhaust! Topped off the radiator & left the cap loose & continued on. When I got home, I bypassed the core again & pulled the heater box out. The core split right down the end of the core tank, maybe 3 inches!! I know I had a good mix of antifreexe in it. Fresh from a flush & new T stat just a couple of weeks ago. So, made a temporary block off plate & am going tomorrow after work to turn in the core & get another one made. Never fails!!! Going to be a cold drive to work tomorrow!! Going to be even colder Monday & Tuesday than today!!!!

Keith I bought a heater core for a 74 chevy truck.
The lenth was the same but the width+height was
A little smaller. And I had to make a differant hole
for one of the tubes. It's alluminium and was only
$37.00 shiped to my door. I eliminated the little
conootin valve thingy. Just a thought. I have the
part number to if you want it.

GT.

Look for a 1984 s10 heater core its d same size for a 63 temp or lemans not shored if 62 is d same as 63

I've got one you might try if you get stuck.

Well,,, my parts book shows different numbers for the 61 & 62 heater cores. I will know tomorrow if they can fix this one or make another. Was awfully cold this morning on the way to work!

They are different. I've got one in a low mileage 61 car. Not being used in 5 years can be an issue, but might be worth a try.

When did you start selling real estate? LOL i wanna move now...

Keith, I was doing some reading and the green coolant can get acidic when in a system with a hot water control valve as it sits and gets stagnant. It went on to say that not only does the stagnant coolant cause leaks it also causes boiler scale inside the heater cores prematurely. It said that was why the newer vehicles don't have them, the engineers figured that the coolant was better left to circulate so the heater cores lasted longer.

The piece said that 2 other things can cause this phenomenon called silicate drop out is hard water being added to the coolant, and too high of a concentration of antifreeze, over 50%. They suggested using distilled water to mix with the antifreeze and said that even if the PH testing was good it can still happen. The article said coolant should be changed at a minimum of every 2 years and where it's subjected to heat extremes even sooner. I'm not sure if this may apply to you or not, just something I learned and thought I'd pass it along.

I too have a couple used 61 complete heater assemblies and some 63's if you want to change it over.

AWFULLY COLD !!!! LOL !!!!

Mid-20's is cold,,,when you are used to the 70's this time of year!! Heat pump went out in the house. No $$$ to get it fix's yet. Was in the 30's in the house when I got up this morning!!

Time to start baking with the oven.

GT.

Unacceptable

Heater Update!!! Still cold in the house but the car was "Toasty" this morning!!! Got the core fix'd & back in!. Had 5 days straight last week with the temps in the 20's & high's in the low 40's. Today was 82 degrees!!!

Testing New & Used heater Cores...
 

A new heater core for the GP included an installation sheet listing a testing procedure to be performed prior to installation. It suggested plugging one outlet and then using your garden hose/house water pressure (about 65# where I live) to pressure test their product.

Using this test since then has resulted in a 50% rejection rate :(.

Somewhat on the subject: the GP's new Ron Davis Racing aluminum radiator had a similar installation/fact sheet that advised grounding all radiators to reduce/eliminate corrosion caused by the electrolytic action of the dissimilar metals and the coolant causing voltage to occur in the cooling system, somewhat like battery.

Les,,,thats crazy!! Using house water pressure to test heater cores??? Whats the average car system run,,12-15 pounds?? My house water will burst a garden hose if left turnd on for any length of time. I am surprized there was only a 50% rejection rate.

Testing...
 

Testing at that pressure must have a correlation to the manufacturer's strength/integrity specs.

That’s not an unreasonable test. Standard home faucets are rated for 80 lbs pressure. The pipes can withstand much more than that. I’ve got 90+ lbs pressure at my house and it takes years to see faucet leaks. Even with thinner wall tubing, I would expect a heater core (no rubber seals and such) to withstand 65 lbs at a minimum. I probably have a manual around here that shows the burst strength of the tubing... if you must know.

At 80 P.S.I. you should have a big safety factor once it's installed in the car. Since copper tubing is usually more malleable than brass and solder joints are used in construction of home water systems as well as radiator and heater cores I don't think 80 P.S.I. is that far out of line for a short term test.

It would be nice if all cooling system components were tested to 80 P.S.I. Maybe there wouldn't be the owner field testing for quality control along with associated warranty and customer dissatisfaction with radiators and heater core that there currently is in the aftermarket product industry. The heater cores currently made in China I've heard of them lasting a year or less. So they'll give you a new one if it fails, big deal, no one is paying for the labor the second time around.

Reputable parts companies going back 20 years or so would help with at least some labor on defective parts, now that is practically unheard of. They exchange the part for you when you present them with the defective part, that's the easy part. It's all about the bottom line and greed, corporate America could give a rat's behind about reputation and standing behind a product that Hop Sing made in a sweat shop on the other side of the ocean.

Typically a split core is either a freeze situation or a lack of a restrictor in the inlet line to the heater core. I typically bend the large tubing to a 3/8" square opening to mechanically reduce the slug of water hitting the guts of the core under hard acceleration. An Old WW-2 Pontiac mechanic told me about the "Mod" after I failed mine from "hard acceleration testing".

If you had properly recirculated anti-freeze to the core then the core did not freeze.
So did you do your recirculation "fill" with the valve open?

Tom Vaught

Seems like 90lbs. would have water bouncing out of the sink and the ceiling.

dig out that part number man!!!!!!! I'll do a build thread if needed.