Originally Posted by xpdude

looked over engine running at opp temp. i noticed some things. 1: bubbles in resovor when on and some when turned off. 2: coolant smells like exaust fumes. 3: hoses hard to squeeze, and both hot. 4: Driving car around, notice coolant overflows in the overflow bottle. top of cap gets wet. fill to MAX line, then it fills up 3/4 way full, and its past MAX mark. 5: had oilly deposit substance on radiator cap an inside resovor on the bottle sides. Oil in engine looks fine with no increase of levels or milky substance on oil cap. things done to car. 1: valvecover pulled and cleaned. no antifreeze present. 2:engine ran 3/4 hot sometimes but never got hot, always pulled over to kool off and add koolant. 3: Thermostate has been changed. 4: aprox 1/2 qt of transmission oil added to engine to clean up (gunk), going to change fluid soon. 5: looked at sparkers, all clean, grey in color. 6: powerwashed engine gay, no leaks present. powerwashed resovor inside, changed coolant. No oil noticed when drained. looked oily like film. 7: New radiator cap from autozone. still driving, haven't got hot in a while. Still see bubbles in resovor. 173k mi on engine, 3rd transmission.

Originally Posted by itsmejto

What a load of crap man, it's a "sealed" system, the cap is airtight and under pressure.
If the pressure exceeds a given psi (14psi ?) it allows water to blow out from the overflow hose to prevent a rupture in the hoses/radiator etc, otherwise it keeps the set pressure and does not leak.