Upper radiator hose leaking at water neck - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kcsa75 · 02-09-2013, 03:25 PM

I recently replaced the intake manifold and water neck on my truck -- SBC 350 -- and now coolant is leaking from the upper radiator hose where it connects to the water neck. I've cinched it down as tight or tighter than it needs but you can see a small drip when the truck is running. The hose is not brand new but less than a year old.

I'm wondering if I could put a thin layer of Permatex around the water neck, if that would help.

Any ideas?

TIA.
Posted via Mobile Device

Sammy · 02-09-2013, 09:41 PM

Try some of the black RTV a thin coat about a 1/8 in bead. Allow it to get tacky n then dry before you refill it. It has worked for me before. I let mine sit over night then refilled the rad.

Andy4639 · 02-09-2013, 10:09 PM

I have done this to, you could also try another clamp beside the orignal one to if you have enough room.

**jocko** · 02-09-2013, 11:06 PM

I've not had luck with permatex or rtv trying to seal cooland leaks - I have had luck doing what Andy said. If you just want to seal it and don't mind having two clamps, it's a very effective method.

Lee H · 02-10-2013, 11:38 AM

I'd try the double double clamp method also. If its an off shore chrome neck you will likely never get it to seal.

**TBONE1964** · 02-10-2013, 11:48 AM

Check the inside of the hose for rust/corrosion. Sometimes rust will stick to the hose from the old t-stat housing.

Is the new t-stat housing clean, meaning no big pits from corrosion? Is it aluminum cast or iron?

There is no reason to use double clamps although it is an easy fix.

**WIDESIDE72** · 02-10-2013, 06:49 PM

Worse case scenario: it's not the hose leaking but where the neck is soldered to the tank (?)

Andy4639 · 02-10-2013, 07:56 PM

Quote:

Originally Posted by WIDESIDE72

Worse case scenario: it's not the hose leaking but where the neck is soldered to the tank (?)

Yep this is a common problem with these years. The motor flexing and pulling on the upper neck all the time. I just had mine redone because of this happening.

AirSpeed · 02-10-2013, 08:16 PM

Quote:

Originally Posted by Andy4639

Yep this is a common problem with these years. The motor flexing and pulling on the upper neck all the time. I just had mine redone because of this happening.

Ironically I just redid mine today! I thought I had a hole at the bottom of my radiator but turned out to be where the upper hose tube pulled away from the tank. Pretty easy fix.
Posted via Mobile Device

02-09-2013, 03:25 PM	#1
kcsa75 Registered User Join Date: Oct 2010 Location: Kansas City Posts: 3,590	Upper radiator hose leaking at water neck I recently replaced the intake manifold and water neck on my truck -- SBC 350 -- and now coolant is leaking from the upper radiator hose where it connects to the water neck. I've cinched it down as tight or tighter than it needs but you can see a small drip when the truck is running. The hose is not brand new but less than a year old. I'm wondering if I could put a thin layer of Permatex around the water neck, if that would help. Any ideas? TIA. Posted via Mobile Device __________________ Willie Swamp Angel Truckers '72 C10 Highlander *People who blindly follow a GPS end up on television programs on The Weather Channel. Some survive, some don't.*

02-09-2013, 09:41 PM	#2
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: Upper radiator hose leaking at water neck Try some of the black RTV a thin coat about a 1/8 in bead. Allow it to get tacky n then dry before you refill it. It has worked for me before. I let mine sit over night then refilled the rad. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

02-09-2013, 10:09 PM	#3
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Upper radiator hose leaking at water neck I have done this to, you could also try another clamp beside the orignal one to if you have enough room. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

02-09-2013, 11:06 PM	#4
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,949	Re: Upper radiator hose leaking at water neck I've not had luck with permatex or rtv trying to seal cooland leaks - I have had luck doing what Andy said. If you just want to seal it and don't mind having two clamps, it's a very effective method.

02-10-2013, 11:38 AM	#5
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,141	Re: Upper radiator hose leaking at water neck I'd try the double double clamp method also. If its an off shore chrome neck you will likely never get it to seal. __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

02-10-2013, 11:48 AM	#6
TBONE1964 Cluster King Join Date: Nov 2012 Location: Junction City, OR Posts: 5,263	Re: Upper radiator hose leaking at water neck Check the inside of the hose for rust/corrosion. Sometimes rust will stick to the hose from the old t-stat housing. Is the new t-stat housing clean, meaning no big pits from corrosion? Is it aluminum cast or iron? There is no reason to use double clamps although it is an easy fix.

02-10-2013, 06:49 PM	#7
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: Upper radiator hose leaking at water neck Worse case scenario: it's not the hose leaking but where the neck is soldered to the tank (?)



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.