overheating problem????

[tumbleweed]

This Saturday, my temp gauge went to over 240. Was working on problem yesterday and have a question. After getting car up to 225, I shut it off and was checking with an infrared gun. At the point of the probe I was getting 179 while gauge was still at 220. Should the temps be closer than that? Maybe my gauge is bad??? Radiator never steamed at track, just pulled off track because of what I was seeing on gauge. Also, my 27-29 radiator cap was bad and put a new one on, but, I could only find a 16# cap. Is the reason for running a higher cap, to keep the fluid in radiator longer? My friend runs a 36# cap. Thanks

[AdamHammer]

A higher # cap raises the water's resistance to boil. At sea level water boils at 212*, higher altitudes the water boils at lower temperatures because the molecules are more spread out. The higher # cap increases the density of the water and therefore raises the boiling temperature.

Have you made sure there is no air in the system? sometimes the temp probes will read an air bubble or steam pocket if it gets caught up there.

[Egoracing]

The higher perssure the water is under the higher the boiling point is. I would test the gauge but I would also test the probe and see if it is off.