Elusive radiator leak...any ideas

[rinnels69]

OK, I'll start from the begining. I was driving the truck home, looked down and noticed the temp gauge was going up...shifted in N and coasted to a stop. Turned the truck off, got out, looked and everything looked OK. Got back in after 5 minutes, started truck...temp gauge went back to normal. Started down the road, no A/C, radio off, and went about 1/2 mile and the temp gauge rocketed back to HOT...shifted into N and coasted to a stop, turned the truck off and got out again and didn't see anything--no leaks, no hissing, etc. A gentleman pulled over and offered his help...put maybe 1/2 gallon of water into the overflow tank. Waited about 15 minutes this time and limped her back home (3-4 miles) with no issues.
Went out the next AM to warm up the truck, came back out after 5 minutes or so and there was a small (a foot or so) puddle under the radiator. Turned it off and drove the Crown Vic (1999 retired cop car). The radiator continued to leak for 3-4 days, but I couldn't see where it was leaking from. So, today I went out and poured some filtered water in (going to do a flush before I refill) and waited for the leak...the bottom of the radiator (looks like a tray the radiator sits in) filled up and began to leak...Hoses are fine--no leaks that I can see......

Here are my questions:
1-Any ideas as to where the leak is coming from? (other than the radiator )
2-Has anyone used a radiator leak additive in a 6.0??? I used to use one that comes in a tube about 4" long and an inch in diameter and it was filled with what looked like silver metallic shaving, maybe 1/16" in size. Is this stuff safe for our trucks?

Sorry so long and TIA for any and all replies!

[obsidian]

DON'T USE THE ADDITIVE! That **** will clog the system and that is the absolute last thing you want!

As far as the leak, from what it sounds like you may have a pinhole leak somewhere in the radiator piping inside of the fins.

[Harleystroked_3310]

I am not 100% sure, but a stop leak in the coolant system seems like a very bad idea. These oil coolers are just sooooo sensitive. I could be wrong though.

[cubalz]

My understanding is that the stop leak will clog your oil cooler for exactly the same reason that is stops the leak in your radiator. It fills small holes. Have you seen a cross section of an oil cooler?

I would get yourself a new radiator installed and be done with it. That would be the right way for sure.

[rinnels69]

Thanks everyone! I'll let ya know what I do and how it works out.

Anyone else???

[dieseldan2005]

Have you checked your egr cooler or head gaskets by chance, just to see if that has been causing any of your overheating issues? I only ask because the coolant might have gotten hot enough and cracked the tank seal on the radiator. It is just rare to see a 6.0 with a bad radiator, not that it doesn't happen, but especially on an 07. The 08's had lots of rad issues.

[rinnels69]

Originally Posted by dieseldan2005

Have you checked your egr cooler or head gaskets by chance, just to see if that has been causing any of your overheating issues? I only ask because the coolant might have gotten hot enough and cracked the tank seal on the radiator. It is just rare to see a 6.0 with a bad radiator, not that it doesn't happen, but especially on an 07. The 08's had lots of rad issues.

This is the first time it has overheated in the 1.5 yrs I've had it...there is definetly a leak somewhere on the radiator, just can't see it without removing the fan and shroud. Looking into a new radiator.

MIGHT try a radiator sealer like Bars "Liquid Copper Sealer"??? Read about Liquid Glass--not for use in diesels.

Why does everything have to be so difficult with our trucks?

[dieseldan2005]

I would NOT use the sealer. Just like others have said, it will plug your oil cooler and then get ready for more costly repairs.

[jd4010]

Originally Posted by rinnels69

MIGHT try a radiator sealer like Bars "Liquid Copper Sealer"??? Read about Liquid Glass--not for use in diesels.

Don't do it! I just spent $1781 dollars at the stealership to get my EGR Cooler and Oil Cooler replaced. Figure out where the leak is coming from and fix it right.