Suzuki: mayonnaise in the engine cap, oil change intervals, coolant level

Question
hey scotty,
as i mentioned earlier, i have water cooling my engine down, and im not sure if the coolant level has gone down, but i've had to top up the reserve bottle a little bit, but the question is, when i took off my oil cap tonight i saw a little mayonnaise colored residue in the oil cap, i looked down through the hole into the engine to see what the oil on the valves looked like, but it looked normal, the car hasn't been overheating, and it's still running at 40 psi while driving, should i be worried about the residue? it's not very much maybe about a couple millimeters in diameter, but it appeared after 20 minutes of driving after wiping the last residue off from the night before, any ideas?

oh btw, your the guy i dump all my questions onto, thanks for all the help,
Geoff

Answer
you are getting that because I'll bet your vehicle  doesn't run for more than a half hour AFTER reaching full operating temperature.  It's normal moisture fron normal combustion blowby, and unless the engine gets and stays at normal operating temp for 30 minutes to an hour minimum, that will happen.  It's part of why short trips are considered "extreme service" when considering oil change intervals.
scotty