Originally Posted by xymotic
I installed a vapor tach a couple years ago, and I've never really been able to get it working right.
For some reason I dinked around with it today and lo and behold the water temp is working which I swear it never did before, but Honestly I don't remember.
40 degree outside, after a pretty lengthy freeway run it's idling at the offramp and it's running 210 and then as it sat there climbed to 240 degrees. Does that seem reasonable or too hot? I've always thought 200 was about max for most motors.
My Vapor with sensor installed in the lower right radiator hose outlet (cold water) to the right side runs well below 200F. Fan comes on at 208F, off about 192 or so. Running down the freeway this time of year it is common to read 140-170F. At a stop light coming off the freeway it will rise quick and turn the fan on.
My TE450 with radiator mounted thermoswitch (just under the rad cap) will hit a max of 220 when the fan has a tough time keeping up. Fan on at 200, off at 190F though. TrailTech coolant temp sensor is on the right radiator upper (hot) hose in the middle of the frame.
If you are really seeing 240F you are probably steaming off, or low on coolant or both. Fan may not be coming on or water pump not doing well? If it is really hot and overflowing you will smell it from the overflow bottle. Be sure to check that level.