1993 JGC with inline 6. Everyday I lose about a quart of water. No sign of water leaking when hot or afterwards sitting in the drive way. Put a big funnel in the radiator to see if I had any head gasket leaks and saw no air bubbles. Pulled all the spark plugs and all look great. No leaking around any hose fittings. Last time I check right after driving it and there was some pressure in the upper hose going to the radiator but not super hard. Removed radiator cap slowly and there was some release of pressure but nothing extreme. The radiator cap says 13lbs. Looks fine but should I try replacing it with a 16lb cap?
I generally am a pretty good mechanic but this one is a head scratcher. The engine is running great.
Any trouble shooting ideas??