melting heater core fittings

[protour_chevelle]

Ever since I put the 6.0l into my Chevelle I have been having heater core issues which is driving me insane. The car runs at 180-215. Mark 8 fan with DC control unit. But it keeps on melting the fittings off the heater core and leaking anti-freeze into the interior. I have put 5 heater cores in the damn thing. I have been using auto value/parts source heater cores. Could this be my issue? Anyone run into a similar dilema?

Are there any alternatives to having heat but a more quality core? Not interested in a/c or a vintage air setup though.

Thanks for any thoughts/insite.

-Matt

[Tiger]

As I understand it its the the solder on the copper core melting.
To solve this you might have a new core built out of aluminum with welds instead of solder.

[CarlC]

Are you sure it's melting something on the core, or is it mechanically failing due to fatigue? The hose will melt long before the core.

Do you have any pictures of the failures and the hose and attachment system?

[dhutton]

Are you running Dexcool antifreeze?

[protour_chevelle]

Its the solder joints that are melting. It shouldn't be fatigue related, the hoses are supported by zip ties onto the dipstick tube due to the downpipe being right there. I am running prestone green antifreeze mixed 70(water)/30

[protour_chevelle]

I just checked the garage and do not have the old ones anymore. The last one that melted is still in the car, I just looped the hoses around so I could drive the car. It is the return line that always melts(bottom) The pipe that comes off the core ends up just blowing out once it melts. I have never had a over heating issue...?

[shep]

If you can find a radiator shop they might be able to braze the fittings back into the core. Should hold up better than solder. Is heat from your turbo melting the solder and causing the failure?

[protour_chevelle]

If you can find a radiator shop they might be able to braze the fittings back into the core. Should hold up better than solder. Is heat from your turbo melting the solder and causing the failure?

Funny you mention that. The last core was rebuilt by a rad shop. I took it back and they said tuff luck. I do not think the turbo heat is related because it wa failing before the install. My downpipe is heat wrapped and ceramic coated so that shouldn't be an issue. This is drivin me nuts.

I wonder if I could get just the heater box/core from vintage that puts all of my water lines inside the fender?

[protour_chevelle]

so I got to thinking some. Was on year ones website... The factory heater hose clamps are like steel o-rings you use pliars to squeeze over. When I first got the car from my grandpa. It had hose clamps on it. Had no issues ever then. But I ended up using t bolt hose clamps on other parts of the car and decided to use them there aswell. I'm thinking maybe just from my he-man-women-hater strength I have always been doing them up too tight, So when everything gets nice and warm it deforms the connection and weakens the joint? Plossible or out to lunchola?

[b-man]

No way could your water temperature ever get high enough to melt the soft solder used to attach the tubes to your heater core.

Radiant heat from your exhaust could be causing it, if the solder is actually melting.

I've never heard of a heater core failing like this, solder melting is very unusual.

Heater cores will fail if you turn high-RPMs. The force of the slug of water coming from the pump all of a sudden will cause them to fail.

Put a restrictor in the heater hose inlet to the heater core. Make up a brass, copper or stainless steel restrictor that will will fit snugly into the inlet pipe on the core.

Drill a 1/8" or 3/16" hole at the largest, it will flow plenty of water and your heater will put out plenty of heat. This fix will keep the slug of water moving at high speed from damaging your core.

This was a factory fix on the old GTOs that were constantly blowing heater cores under warranty 'back in the day'.

[tumper93]

I agree with b-man, a car can overheat at 260° and the heater core never fails at the joints. Newer suv's with the ls motor has quick disconnects made of plastic and those would fail first but also never doo just like the cores doesn't. More than likely the down tube for your turbo is causing a heat problem and is what is melting the solder. No way on earth 185-210° coolant temp is going to make solder joints fail. Soldier has to be heated to appro 217°C to become fluid so I would be looking at a radiant heat source as the problem.

[protour_chevelle]

hmmm interesting points! I do run the car super hard. Spin it high and repeatedly. I'll have to try that restrictor idea. I also just double wrapped my downpipe off the turbo. Hopefully that helps too.

[JEFFTATE]

Could it be ELECTROLYSIS ?
Maybe the solder is being erroded by electricity.
You may have a bad ground on the engine and the electrical system is trying to complete a ground through the coolant.

Don't laugh , it happens !

Here's a link :https://www.pro-touring.com/forum/sh...t=ELECTROLYSIS

[protour_chevelle]

Could it be ELECTROLYSIS ?
Maybe the solder is being erroded by electricity.
You may have a bad ground on the engine and the electrical system is trying to complete a ground through the coolant.

Don't laugh , it happens !

Here's a link :https://www.pro-touring.com/forum/sh...t=ELECTROLYSIS

Crazy, I'll have to try that once I get a new heater core back in there! Thanks for the tip!

[Mike Holleman]

Matt, Just a thought. When you install your hoses to the core, are you using a twisting motion or working the hose side to side? If it's not leaking from the get go forget the question.
Mike

[CarlC]

The solder used in cores melts around 400*f. If the joint is getting that hot then something else is about to catch on fire.

My money is on either electrolosis or a mechanical failure.

[protour_chevelle]

so I did this test according the the article. If I let the car sit and idle, put the positive in the coolant it jumps to 6 volts then will slowly work its way down to 1 volt or less... My question is, how in the heck do I put ground straps on my heater core and rad?

My only real concern is this. My gauges are grounded to the body, body is grounded to the block, block is grounded with 2 straps to the frame, fan is grounded to frame, fuel pump grounded to frame, and engine has the factory 5 or 6 grounds to the block. battery is grounded to the block.

Should I also ground the battery to the frame?

[andrewb70]

If you need a restrictor, JTR (Jags That Run) sells a nifty little fittings that will let you take the 3/4" hose to 5/8" hose and is also a restrictor.

Andrew

[protour_chevelle]

If you need a restrictor, JTR (Jags That Run) sells a nifty little fittings that will let you take the 3/4" hose to 5/8" hose and is also a restrictor.

Andrew

What a nifty piece! Thanks for the info!

[protour_chevelle]

Just an update. I added the box of baking soda and it did the trick. Idled the car for 5 minutes and the max the meter got was .25. Far cry from 6.0v LOL