![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,395
|
Hose leak a sign of a bad radiator cap?
After much time today the leak about my lower radiator hose at the pump appears cured after exchanging the #15 RC15 cap for a #15 example I had on the shelf from a Vega coolant recovery system.
Originally I thought the leak was do to loosening of an OEM tower clamp. Tightening before and after repositioning didn’t fix the leak neither did adding a buddied up worm drive clamp. I was ready to replace the hose and clean the pump neck when I thought to try a different radiator cap. Could a bum radiator cap produce the leak? Nothing ever leaked from the overflow hose. Inline tube reproduces an RC15. I plan to order one as a more permanent replacement.
__________________
1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 ![]() |
![]() |
![]() |
![]() |
#2 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,440
|
Re: Hose leak a sign of a bad radiator cap?
Get a light and a mirror and check the weep hole on the bottom of the water pump. If changing clamps didn't help, it's probably water pump bearing seal. I couldn't tell you why the cap made a difference, unless it doesn't actually hold much pressure.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
![]() |
![]() |
![]() |
#3 |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,921
|
Re: Hose leak a sign of a bad radiator cap?
The only way I could imagine a cap causing a leak other than at the cap itself is if the spring is holding too much pressure. I've never seen a cap do that - when they fail, they don't hold enough pressure. Besides, you'd have to have something else wrong that would cause that type of high pressure.
Here's another possibility - the Vega cap is holding less pressure, so the cap that is working exposed the leak, but running the system with lower pressure keeps it from leaking.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
![]() |
![]() |
![]() |
#4 |
Senior Member
![]() ![]() Join Date: Sep 2008
Location: Harrison, Arkansas
Posts: 9,815
|
Re: Hose leak a sign of a bad radiator cap?
I'd say the old cap could have been holding more pressure, therefore causing the leak.
I agree with Steve about the water pump possibly leaking out the little hole in the bottom. I have seen them leak intermittently before they completely fail. There is still a good chance you will end up cleaning the outlet on the water pump. I too, still use tower clamps.
__________________
other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless. |
![]() |
![]() |
![]() |
#5 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,395
|
Re: Hose leak a sign of a bad radiator cap?
Thanks guys. Sounds odd I know. Each cap involved is 15lbs. I’ll double check but when I was watching the leak I didn’t get a sense that the fluid trail led to the weep hole. If present, it would certainly be par for my luck this week with engines. Temperature is running normal.
I’ll make a longer run this evening and see what shakes out.
__________________
1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 ![]() |
![]() |
![]() |
![]() |
#6 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,440
|
Re: Hose leak a sign of a bad radiator cap?
If it is the water pump seal, drive it around and warm it up, then park it where the leak doesn't make a mess. Once the engine is off, it'll start leaking once the pressure changes. Crazy that it may only leak when shut off, but I've seen it many times.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
![]() |
![]() |
![]() |
#7 |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,921
|
Re: Hose leak a sign of a bad radiator cap?
Go to your local auto parts store and rent a pressure test kit. You'll be able to test your system and your radiator cap and see where the problem is.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
![]() |
![]() |
![]() |
#8 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,395
|
Re: Hose leak a sign of a bad radiator cap?
Thanks again guys. It’s leaking still. When all this began there was a small puddle. That certainly improved with attention to the lower hose clamp. However, the drips persist and occur when the engine is running making a mess of the front differential cover. What I’m seeing now could be from the weep hole. I’ll work to confirm that.
I’m going to stock up for a water pump exchange when time allows. Can’t hurt to have spare parts on hand if by chance it isn’t the pump. The radiator that’s in place is a Harrison four row but doesn’t have the take off for the water heater. I’ll exchange it for a rebuilt one I have on hand that does have a take off. The build goes on forever, the party never ends.
__________________
1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 ![]() |
![]() |
![]() |
![]() |
#9 |
Proprietor of Dale's Corner
![]() Join Date: Nov 2012
Location: Vacaville , CA
Posts: 16,130
|
Re: Hose leak a sign of a bad radiator cap?
I bet it's the pump, but I'm watching to see what you find out.
__________________
"Some Days Chickens And Some Days Feathers" Dale XNGH ECV Sam Brannan 1004 R.I.P. 67ChevyRedneck R.I.P. Grumpy Old Man |
![]() |
![]() |
![]() |
#10 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,395
|
Re: Hose leak a sign of a bad radiator cap?
Engine is cold - I’ll check at operating temp but weep hole looks clean and dry at rest. No coolant residue.
I’m tempted to add an iPhone endoscope attachment to my tool box for tight inspections like this. https://www.amazon.com/DEPSTECH-Wate...=fsclp_pl_dp_1
__________________
1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 ![]() |
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|