QuestionHi Scott,
I have a 71 GT6 that is pegging the temp gauge during drives in the South Carolina summer. My non-contact thermometer reads 205 degrees when the gauge is hot. I have replaces the anti-freeze with a 30% mixture, pulled out the thermostat, and added the correct shrouding. What do you suggest next? Also, the temp. sending unit reads 10 volts, is this too high and may partially explain why the gauge reads high?
Any help would be appreciated. Thanks, Jon
AnswerYou shouldn't need to remove the thermostat; that is going to cause you take the engine longer to get up to the correct temperature (most efficient, most power)
From everything I have read, 10V = 200+ is correct. You could get an aftermarket gauge that has degrees on it as a test, but it will probably tell you the same as what the stock gauge is saying.
It could be a number of issues,
1) radiator blocked/needs recore/uprated radiator needed
2) cracked head (blowing combustion gas into coolant)
3) timing too far advanced
4) mixture too lean
5) shrouding not maximizing air flow
6) pipe from water pump to heater core or radiator hoses collapsing/blocked
Try running the heater inside the car when the temp is pegged and you are driving at speed. If that brings the temp down, then you know upsizing the radiator will help. That won't, however, fix the source of the heat.
Adding an electric fan would be similar, it will increase the air flow at idle & lower speeds, but doesn't fix the source of the heat.
Read this gentlemen's cooling story; he had the same dilemma as you, but with a spit. Your problem may be one that he tried, but didn't solve his problem...
http://www.kosier.net/spitfire/cooling.htm
