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lfc 10-28-2009 10:52:40 70.138.14.189 455607 Report to Moderator	I"m working on a "68 2000 gas, that now thanks to a new Zenith carb runs great. Problem is it always runs hot on the gage - up near or even on the red. Old thermostat tested out ok, but I changed it anyway with the correct CNH part, and it is installed correctly (spring end in the manifold). Still, the gage slowly works it"s way up to red. I don"t have an IR thermometer, but by feeling the hoses I can tell that the thermostat isn"t opening until it gets up to red. When it does open, top tank reads in the 180"s, which I would guess is about right. I then replaced the sensor with a new CNH part - same thing. The fuel gage works fine, so I don"t think it is the voltage stabilizer. I read here a few weeks ago about drilling a hole in the thermostat, so I started with a 9/64" hole in the old tstat. That made it run too cool, so I went with a 1/16" hole in the new tstat. It is better then it was, but still I think I need to go a little bigger with the hole. So, although I think I can dial in the hole size and get this to work, is there something I am missing? Is the set point of the tstat just too high or is the hole the answer? We used to have a 3000 gas, and while that would run hot at times, it was never this bad. Can the gage simply go out of calibration - maybe it is reading red too soon? I couldn"t find any specs on it in the Ford shop manual. Thanks. [Reply]   [No Email]
Jerry/MT 10-28-2009 17:35:16 206.183.116.129 455626 Report to Moderator	Re: 2000 Cooling Temp Issue in reply to lfc, 10-28-2009 10:52:40   Could be your gauge and theromostat are OK and the problem is elsewhere. Make sure your timing is correct and/or the mixture is not adjusted too lean. They can cause higher cylinder head temperatures. Also make sure that you rad cap is the correct pressure and working properly, your water pump drive belt is tight and your lower hose is not collapsing. Is you radiator air side clean? Dirt and chaff can cause the coolant tempertures to increase. What"s the rad core look like. They can get limed up from using hard water.   [Reply]   [No Email]
sotxbill 10-28-2009 11:12:39 12.175.208.130 455608 Report to Moderator	Re: 2000 Cooling Temp Issue in reply to lfc, 10-28-2009 10:52:40   the hole is only for getting the thermostat to open early, and over heat and then open. the hole is not to control the temp after its warmed up. Due the thermostat being on the intake manifold, the engine can get very very very hot and the themostat will still be around cold water. the very small hole the side of a pencil lead, will allow the warming water to move toward the themostat quicker and have it open correctly, and not after the engine has over heated. If the top of the tank reads 180, the gauge should be in the middle. or just to the right of middle. your gauge is off a bit. If your thermostat is a 180 themostat and your reading that temperature in the top of the radiator tank, then you can take apart the gauge assembly and carefully bend the gauge needle just a bit to the left so it shows correctly. or you can try to find a replacement gauge. 200 should be close to red. 220 should be at edge of red. good luck. Bill   [Reply]   [No Email]
lfc 10-28-2009 13:24:57 70.138.14.189 455616 Report to Moderator	Thanks in reply to sotxbill, 10-28-2009 11:12:39   I feel better now. The tstat is actually a 188 - that may be high but that is what is called for. If the gage is red at 200, by the time the tstat gets hot enough on the radiator side such that it opens the engine could well be up to 200. I'll make the hole in the tstat a little bigger to get it to open a little sooner, and call it good. Thanks for the advice.   [Reply]   [No Email]