Radiator Cap & Leaking?

Thomas · Post by **Thomas** » Sun Dec 11, 2011 9:02 am

In the last two months, I have been getting some leakage from my radiator through the overflow drain. I loose about a cup of fluid on each drive. I think I know what the problem is, but I would like to get some feedback from the group.

Thanks for any help you can give me.

Thomas
Charlotte, NC

Post by **wesk** » Sun Dec 11, 2011 10:32 am

1-Cylinder pressure leak into water jackets. after the engine warms up and with the cap off look for bubbles in the coolant at the top of the radiator when moving the throttle up and back.

2-Sticking thermostat. Should show up as a higher than normal operating temp.

3-Blocked radiator core. Try reverse flushing.

GPA · Post by **GPA** » Sun Dec 11, 2011 2:14 pm

Rad cap hold pressure?

artificer · Post by **artificer** » Mon Dec 19, 2011 3:40 am

Get a radiator pressure tester which will check the cooling system inegrity & the radiator cap. Some folk think they have a problem & keep topping up for the excess coolant just to overflow continually.

Thomas · Post by **Thomas** » Mon Jan 02, 2012 11:56 am

Gentlemen;

Thanks for the information and help. I did a test today, and here is what I did and observed:

1. Removed the cap and found the water level just above the top of the core
2. Filled the radiator to the top,...just below the opening
3. Started the engine and warmed warmed it up
4. The thermostat housing warmed up, then the radiator intake area at the water inlet hose warmed up
5. As the water expanded it rose above the radiator drain inlet
6. As it rose, water droplets "danced: at the radiator

Thomas · Post by **Thomas** » Mon Jan 02, 2012 12:07 pm

Continued:

7. There were no air bubbles as I increased the engine speed.
8. As the engine warmed up and the water circulated, the water temp seemed to equal out
9. I shut off the engine and the water level settled out just above the radiator core
10. With the engine off, I did observe two or three large bubbles work their way to the mouth of the radiator opening.

I then drove the Jeep for about 20 minutes and everything seemed fine. After the drive, once the engine cooled down a bit, I removed the cap and observed the water level was a little bid lower than when I started my drive.

Any thoughts? I believe my thermostat is fine. For now, I think I will try a radiator flush first and observe from there.

Thomas
Charlotte, NC

Post by **wesk** » Mon Jan 02, 2012 12:09 pm

5. As the water expanded it rose above the radiator XdrainX OVERFLOW inlet
6. As it rose, water droplets "danced: at the radiator WHERE

This is normal.

The test that needs to be done is a pressure test of the cap with a real pressure tester. If the cap relieves pressure too early then you will have overflow at the overflow tube (this is not a drain tube) prematurely. If you overfill the radiator then lacking room to relieve pressure raw coolant will get expelled first.

Your test has only shown you how the system operates. As the coolant gets warm it expands. If you have over filled the radiator coolant will be expelled for a short while.

Take your cap to a quality well equipped auto repair shop and have them test it.

Do not overfill the radiator. Leave at least 1 to 2" of expansion space between the level of the coolant and the bottom of the filler neck.

Thomas · Post by **Thomas** » Mon Jan 02, 2012 1:43 pm

Wes;

Will do. Thanks again for your help.

Question: any recommendation on a brand of radiator flush?

Regards;

Thomas
Charlotte. NC

Post by **wesk** » Mon Jan 02, 2012 10:24 pm

I think you should work one issue at a time.

I do not recommend any gooey agents being pumped into the cooling system. The best course of action when a cooling system is suspected of being stopped up is pressure reverse flushing with plain water and air.

If the stoppage is obvious and reverse pressure flushing doesn't clear the system then remove the radiator and have it professionally hot tanked.