Strange radiator leak

[EricG]

Ever since I did the PHH a few weaks ago I've been trying to figure out where my coolant is going??? I've probably added about 2 gallons in the past 1000 miles. But no puddles in the parking lot, no smoke on startup or while running, no apparent water in the oil or vice-versa. I've been under the hood & under the truck with a flashlight hot & cold, running and not - nothing.

Then today I had to take my daughter to school - only about 4 miles. When I came out I saw a steady dripping. Opened the hood and confirmed that it's coming from the radiator petcock area. Drove to work, made one stop about 10 miles along. No leaking at the stop or when I got to work.

So - it only seems to leak when warm? Not hot, not cold. The only thing I can figure is that the window of opportunity is when the radiator has started to develop some pressure, but when it get's hot, whatever is leaking expands to close it off. Strange.

I'm going to pull the petcock this weekend and take a closer look - maybe it's cracked or the o-ring is damaged. Any other ideas??

 

[-Spike-]

Dirt may be in the seat for the petcock. You might try opening and closing it a few times.

-Spike

 

[CJF]

Petcock is a funny word...;p

 

[-Spike-]

Don't be makin' fun of my petcock...

-Spike

 

[TLC42TD]

If it's one more than 100k, it probably needs replacing. Inspect the radiator up close and look for signs of decay. The symptoms you describe suggest small holes that release coolant under pressure from a hot engine, and these will only get worse over time. Replacement is an easy diy job but takes a couple of hours.

 

[Brentbba]

I've got a brand new one and a brand new thermostat I no longer need that I'll sell you.

Cracked a radiator yesterday, so will be getting all new stuff. Truck is in Valencia and these new parts were 90 miles away at home.