Hey Guys/Gals, new to the forum. Wondering if someone can help me out.
The temp gage on my E350 (460 engine) reads low even after its at operating temp. It does come up off full cold, but not much. Am trying to find what the resistance of the temp bulb should be cold vs hot. I get 370 ohms cold and 55 ohms hot. Was wondering if the 55 reading is a little high and not driving the temp gage needle to mid band where it should be, but the Chiltons book I just bought for it doesn't have anything on it. Its got the 460 carberated engine and the 1 terminal screw-in temp sensor at the front of the intake. I know the sensor is probably $10-15, but I like to verify the parts actually bad before I start swapping out parts. Also, is there a better maint book I can buy for this rig other than the 1961-1988 all encompassing Chiltons E-sereies book I have now? It doesn't have much in the way of wiring at all. Its actually a Jayco Mini RV on the Ford chassis.
Thanks, Jamie

 

How hot is your hot?

To find out if your engine is actually warming up to temp you need one of these.

Infrared Thermometer

or

Non-Contact Laser Thermometer

 

When at operating temp, the engine is hot. I don't have an infared thermometer, but my main concern is if the gage is only going up to the cold mark when the engine is hot, if it does start overheating it would barely go above where it is now. I was expecting it to be about 1/3rd of the gage when at operating temp. Just trying to find out the range of the sensor (resistance vs temp).

 

You are making assumptions and have no facts. Engine are designed to operate at 200° and up in today's EPA driven world. But at 140° the engine will feel hot to the touch, hell it will blister you. If you assume that 140° is 200° then everything you surmise is wrong after that assumption. Factory gages are notoriously inaccurate. Either get an infrared tester of install an after marked gauger. The smart money is on the infrared. Whether the gage is reading correctly is irrelevant until you KNOW at what temp the engine is operating at.

 

I changed the $10 sensor and now the gage reads midband like I expected it to read. I checked the new one in some boiling water and the resistance went down to 35 ohms so good indication it would swing the gage more to the midband. Was a pain getting the new one to start threading with no room for any fingers to help it start. Lost about 3/4 of a gallon of antefreeze...only had a 1/2 gall on hand. Man have they raised the price of that stuff or what! $13/gallon!!!