Just attended the Good Guys event in Indy. Got to talking about my 71 running hot. A guy ask if it ever boiled over and I told him no. I said it runs about 210 when running slow or in traffic. My buddy had his 40 Ford there and said he had the same problem. The guy pulls out a laser temp gauge and said go try this. We ran the 40 till she got hot then took a reading. The gauge said 225 and the laser said 185. We have SW and VDO in our cars. Brand names don't insure accuracy or does it just take more money to get good gauges?:(
How do you know that you are buying accurate gauges other than what the company says. I am sure a lot of time and money is wasted by people like me trying to fix a bad gauge.
Allen

if the sender is located in the head you'll get a higher reading than if it's located in the water outlet... the water neck is the return and with the hole in the head so close to the exhaust, naturally it'll read hotter there... now a cheap gauge CAN read off what the true temp reading is... you might try sticking the sender (mechanical) in a pot on the stove and use a separate testor to confirm reading ;)

How do you know the laser temp reader was accurate?

to me it sounds like the coolent is doing its job. Its hotter then the outside of your motor cause it has absorbed heat from your motor. As Johnny said if the sending unit is in the head it will read a hotter temp then your water outlet. Now I'm not so sure the head is hotter then the water outlet cause its closer to the exhaust personally I think its because its closer to the combustion chamber (you know the place where a lot of the heat is generated in the first place ;) ) BUT then again WTF do I know:o:)

Water boils at 212 degrees at sea level (slightly lower at higher elevations). All you have to do is drop the mercury bulb into a pot of boiling water and see what the gauge says. If you have an electric gauge it is measuring resistance, and accuracy will depend upon whether your car has any other electrical problems as how accurate it is. Because every electrical gauge only measures voltage it relies upon an accurate source of power and a good ground; for this reason I rely upon mechanical gauges rather than electric.

Big Dave