Coolant loss

[suobs]

My 1994 4x4 King Cab D-21 pickup, manual transmission, 4 cyl engine seems to be losing coolant. I've topped the reservoir twice to just above the minimum level (with engine cold) twice in the last 3 weeks. According to a shop manual I have (Chilton), the colorant in the coolant (Prestone - greenish yellow) should make it easy to spot a leak, but I'm not seeing anything greenish or even wet-looking anywhere after running the truck, at least in the places I've thought to look (around hose ends, radiator drain, under the radiator, surface of the skid plate, and the ground under the truck after driving).

Any ideas or should I just assume I didn't get it filled right the first time? I'm planning on flushing it soon.

[Saudade]

Check your cap. If it's not sealing properly, you can loose coolant there. Of course, you could be burning it. Any signs of white smoke out the tailpipe?

[suobs]

Burning it? That doesn't sound good . . . am I looking for white smoke when idling? Accellerating? When engine is hot or cold?

Cap looks fine but I'll get a new one.

[Towncivilian]

Yeah, inspect your radiator cap according to this TSB. Replace it with a new OEM one if necessary.