Slow coolant leak. Puddles up underneath truck.

[seanagins]

Ran UV dye through the cooling system. Trying to figure out exactly where the small leak is coming from. I am preparing for a radiator replacement, but want to perform some diagnostic work before spending that money. Plan on renting a pressure tester tomorrow and bringing the cooling system up to pressure while investigating with a uv leak dye light. Any other tips or advice? Oh, I plan on testing the radiator cap as well if I can.

 

[MikeG]

Let it idle and come up to temp, mine did that and there was a bulge when it was under pressure that was the leak. Closed back up when it cooled down and much less obvious. New rad on the way from Rock Auto

Get all the hoses while you're at it, at 23 years mine was living on borrowed time.

 

[seanagins]

Its a 1997 ford ranger, 132,000 miles, and it is a 4.0 liter OHV.
The dye that I use is UV ray activated and is a bright green hue under UV light. Night time helped a little. I was lucky enough to be able to rent a loaner coolant pressure tester this morning and utilize it while it was still quiet out. I heard the stream of a leak of coolant as I brought it up to 16psi (1.1bar). Come to find out I just needed to tighten 2 of my replacement hose clamps from when I replaced the upper and lower radiator hoses from when I winterized it.

 

[mikkelstuff]

Look for small leaks where the timing case cover seals to the engine block. These aluminum timing case covers are notorious for corrosion and, hence, leaks as in my 3.0L.