Antifreeze leak

[lkf53]

I was told by a friend that the small antifreeze leak I have in my 99 silverado 5.3 was coming from one of the two lines that routes from the transmission to the radiator. I thought those lines carried transmission fluid in them? thanks for any help

[lkf53]

Taking it to a qualified mechanic was a good move on my part! He.......pressure tested cold @ 35 lbs, no leak. Tested at running temp @35 lbs no leak!. He followed the trail of antifreeze to the hose that comes from the overflow tank. He said that at some point the thermostat may have failed to open causing it to overflow out the hose, replacing thermostat refilling system, no charge for the test. $150 out the door! thanks for your help! Im sure with this project truck I have ill need your expertise often LOL...........

[Duelin]

I hope so.

[gmtech4]

red oil ,orange coolant who knows what they mean lol

[Doug_Scott]

I was told by a friend that the small antifreeze leak I have in my 99 silverado 5.3 was coming from one of the two lines that routes from the transmission to the radiator. I thought those lines carried transmission fluid in them? thanks for any help

 

Have to ask, what does your friend do for a living? From what you say, and if your friend is right, it must be the fitting in the rad tank where the transmission lines are connected. It is not the transmission line leaking, it would have to be where the fitting goes through the rad tank.

[lkf53]

To save a headache I dropped the truck off at a RELIABLE repair shop, they're going to do a pressure test to find the leak. He gave it a quick look and told me he is leaning towards a freeze plug rusting out, but he told me he'd go over it and call me to let me know for sure. There is no antifreeze in the oil, starts and runs smooth, keeping my fingers crossed lol, thanks for all your input, it is appreciated.

[Doug_Scott]

To save a headache I dropped the truck off at a RELIABLE repair shop, they're going to do a pressure test to find the leak. He gave it a quick look and told me he is leaning towards a freeze plug rusting out, but he told me he'd go over it and call me to let me know for sure. There is no antifreeze in the oil, starts and runs smooth, keeping my fingers crossed lol, thanks for all your input, it is appreciated.

 

If it ends up being a core plug, chances are good that all the core plugs at that level will be not far behind. By same level I mean if it is the lowest core plug on the side of the engine block, look for another core plug to the left and right of the leaking one. They will rust out if there is a lot of "sludge" inside the water jacket laying against the plug. That sludge will be at about the same level through out the block.

I really wish manufactures would just spend the extra $8 and use screw in core plugs. They could even raise the price of the car $25 and anyone in the know would be happy to pay it. It would also make flushing the block out a hell of a lot easier.

[txab]

The lines should only carry trans fluid, not coolant. You need to look closer. There may be coolant on the lines that is coming from somewhere else and dripping onto the lines. Make sure your friend knows the difference between coolant and trans fluid

 

Check:

 

Water pump and wp gaskets

 

all hoses and hose connections

 

Also check where the coolant line enter the radiator. There maybe a trans cooler leak at that point

[Duelin]

Food for thought. 35 lbs is a lot of pressure. That is a good way to blow a radiator or heater core. I usually don't go more than 5 lbs over what ever the cap is rated for. That the reason you have a pressure relief radiator cap is to relieve unwanted high pressures so you don't blow the radiator.

[rdnkcpa]

 

The lines coming from the transmission have trans fluid in them, not coolant.

[lkf53]

I understand that. I believe it should have been around 15 lbs, I WAS concerned when he told me he pumped it up to 35 lbs, but if it blew anything, it was on him. Everything seems to be fine.

[00Silverado4x4]

I think he meant pressure testing the block at 35 psi.