water temp gauge

A few days ago i decided to install a water temp gauge on my 1990 buick lesabre. I got an electric one made by sunpro off ebay. I found a spot in the intake manifold water passage just below the temp sensor for the fan/idiot light to put the one for the gauge. When i removed the plug in the hole, obviously some of the coolant came out. When i finished installing it i put some more coolant in the overflow tank to replace what came out. When i started the car up, the guage indicated that the motor was at 210 degrees. I figured this was the normal operating temp for my car. The next day while driving to work, the gauge showed almost 230 degrees. I stopped and checked under the hood as soon as i could. the fan was not running and the engine did not seem overly hot. I thought that there might be an air pocket by the sending units (i never checked for this after i put the sending unit in; the sender for the fan/light is above the gauge one so i thought the fan/light one might not be immersed in coolant) so i took off the radiator cap and let the engine run, but no air bubbles came up. could the problem be the sending unit? Has anyone had any experiences with sunpro gauges? If the engine really did get to 230 degrees is there a good chance i cracked my heads? Thanks for the help!!!

230 does seem a bit warm, but its still in the normal range.
Generall, a vehicle only over heats when the coolant starts to boil. If you have a 50/50 antifreeze mix and a proper radiator cap, so the system pressurizes, its good for 260 degrees, or so.
If your car has a 3800 V6, its a cast iron engine and is not particularly harmed by high operating temperatures.
I would suggest changing the thermostat though.

thanks for the info. I feel better knowing that i didnt harm the engine. the thermostat is only a year old, but i think i'll get a new radiator cap as i have no idea how old it is and if it is correctly pressurizing the system. if i did have an air bubble though, how much could the operating temp be raised? thanks again!!!!

If you get a "bubble" around the sending unit it can read high because the evaporated coolant surrounding it is much hotter than the liquid. Steam can be very hot, but liquid water can never exceed 210 degrees. Coolant/water is good for 260 or so above that it evaporates. Let it run a couple of days and see if it clears. Good Luck.

ya make sure its not all coolant because water is a better coolant than antifreeze, the only benefit antifreeze provides...lies in its name. And prevents corrosion

ya make sure its not all coolant because water is a better coolant than antifreeze, the only benefit antifreeze provides...lies in its name. And prevents corrosion
uh...not quite. Yes, water is more conductive to heat, but coolant has the higher boiling point. A car can boil over on straight water, even with the pressure cap, but a coolant mix will keep going.
Don't use straight water. If you do, electolytic corrosion between the aluminum and iron parts in your engine will erode all the aluminum parts to the point of uselessness in about a year or so.

is there an echo?

does anyone know the normal operating temp/ range of the series 1 3800 found in the lesabre?