Newish Radiator with Leaking Cap Neck Joint - The 1947 - Present Chevrolet & GMC Truck Message Board Network

badpeanut · 12-09-2010, 10:02 PM

I have a newish (~6 years old but still in excellent condition) 4-row radiator in my Blazer, but the radiator cap neck where it meets the tank is leaking. I can actually wiggle it a bit. I can easily access the outside of this joint, but what should I use on it? JB Weld? Solder of some type? Is there any way to fix it right without removing it? I have a propane torch, but no oxy-acetylene.

**LockDoc** · 12-09-2010, 10:33 PM

-
It should be relatively easy to solder. The hard part is getting it clean enough to do so... It has to be shiny brass all the way around at the joint, coat with paste flux and solder with a small torch. You have to be careful not to get it TOO hot or you will melt the solder out of the top tank joint... I would go to a radiator shop and see if they could fix it in the truck for you.

LockDoc

eagleuh1 · 12-10-2010, 12:15 AM

Cheap fix at radiator shop. Not so cheap if you melt the solder and make it leak in other places like stated above.

Sillyoldman · 12-10-2010, 12:18 AM

Just solder it back on. Easy fix. Kinda fun too.

cdowns · 12-10-2010, 12:27 AM

you can try to fix it yourself if you scew it up bad you can buy a new radiator

or you can spend a little bit of money and have a pro do it right

**Zeke's Garage** · 12-10-2010, 11:14 AM

If you're a true tinkerer, and you can't help but to monkey with stuff that you KNOW you should leave alone (Me!). Go ahead and take a stab at reflowing the solder yourself.

Clean the area with a stainless steel wire brush and slowly heat the area until you see the solder start to flow. A lot of the times the existing solder will reflow and fill the leak, but you might need to add a bit of plumbing solder depending on how it flows.

This is easier if you have some way to pressurize the radiator and spray the area with soapy water to check for leaks. I made one out of PVC with a valve and pressure gauge that connected both the inlet and outlet ports and filled it to about 16psi.

If you happen to totally hose it up, then by all means take it to a professional... and blame the crazy soldering on the PO... That's just the way of nature.

Good luck!

eagleuh1 · 12-10-2010, 11:28 AM

Zeke, I like that.

Longhorn Man · 12-10-2010, 06:49 PM

it should be a $25 fix at a rad shop

badpeanut · 12-10-2010, 09:40 PM

I called around today. There is only one shop in town that does this work (otherwise I need to travel 40miles or 100miles to the next towns that offer this service). They figure about 1hour of labor / $65.

12-09-2010, 10:02 PM	#1
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,759	Newish Radiator with Leaking Cap Neck Joint I have a newish (~6 years old but still in excellent condition) 4-row radiator in my Blazer, but the radiator cap neck where it meets the tank is leaking. I can actually wiggle it a bit. I can easily access the outside of this joint, but what should I use on it? JB Weld? Solder of some type? Is there any way to fix it right without removing it? I have a propane torch, but no oxy-acetylene. __________________ '05 Chevy 2500HD 4x4 '72 GMC LWB 4x2 driver '72 Chevy LWB 4x4 plow truck '71 Blazer 4x4 driver '70 GMC LWB trailer

12-09-2010, 10:33 PM	#2
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,774	Re: Newish Radiator with Leaking Cap Neck Joint - It should be relatively easy to solder. The hard part is getting it clean enough to do so... It has to be shiny brass all the way around at the joint, coat with paste flux and solder with a small torch. You have to be careful not to get it TOO hot or you will melt the solder out of the top tank joint... I would go to a radiator shop and see if they could fix it in the truck for you. LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

12-10-2010, 12:15 AM	#3
eagleuh1 Registered User Join Date: Jul 2009 Location: Russellville, Arkansas Posts: 1,699	Re: Newish Radiator with Leaking Cap Neck Joint Cheap fix at radiator shop. Not so cheap if you melt the solder and make it leak in other places like stated above.

12-10-2010, 12:18 AM	#4
Sillyoldman #16876 Join Date: Apr 2005 Location: Auburn WA Posts: 12,266	Re: Newish Radiator with Leaking Cap Neck Joint Just solder it back on. Easy fix. Kinda fun too. __________________ Posted via Stationary Device '71 Custom Deluxe C-20 402. '67 Buick Special 455. '49 Plymouth Special Deluxe. *"I love that old car smell"* *Some people are like Slinkies... not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.*

12-10-2010, 12:27 AM	#5
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Newish Radiator with Leaking Cap Neck Joint you can try to fix it yourself if you scew it up bad you can buy a new radiator or you can spend a little bit of money and have a pro do it right __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

12-10-2010, 11:14 AM	#6
Zeke's Garage Senior Member Join Date: Feb 2010 Location: Kennesaw, GA Posts: 288	Re: Newish Radiator with Leaking Cap Neck Joint If you're a true tinkerer, and you can't help but to monkey with stuff that you KNOW you should leave alone (Me!). Go ahead and take a stab at reflowing the solder yourself. Clean the area with a stainless steel wire brush and slowly heat the area until you see the solder start to flow. A lot of the times the existing solder will reflow and fill the leak, but you might need to add a bit of plumbing solder depending on how it flows. This is easier if you have some way to pressurize the radiator and spray the area with soapy water to check for leaks. I made one out of PVC with a valve and pressure gauge that connected both the inlet and outlet ports and filled it to about 16psi. If you happen to totally hose it up, then by all means take it to a professional... and blame the crazy soldering on the PO... That's just the way of nature. Good luck!

12-10-2010, 11:28 AM	#7
eagleuh1 Registered User Join Date: Jul 2009 Location: Russellville, Arkansas Posts: 1,699	Re: Newish Radiator with Leaking Cap Neck Joint Zeke, I like that.

12-10-2010, 06:49 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Newish Radiator with Leaking Cap Neck Joint it should be a $25 fix at a rad shop

12-10-2010, 09:40 PM	#9
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,759	Re: Newish Radiator with Leaking Cap Neck Joint I called around today. There is only one shop in town that does this work (otherwise I need to travel 40miles or 100miles to the next towns that offer this service). They figure about 1hour of labor / $65. __________________ '05 Chevy 2500HD 4x4 '72 GMC LWB 4x2 driver '72 Chevy LWB 4x4 plow truck '71 Blazer 4x4 driver '70 GMC LWB trailer

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