QuestionI have a 1967 dodge a 100 van with a 225 six in it.I'm running a 180 thermostat but my temp. gauge reads 220.The gauge and sending unit are both new.Should the temp. be that high.
AnswerThe temp gauges are notoriously inaccurate, so before you do anything else, go to your local supermarket, to the housewares department, and find a candy thermometer. It is a giant version of the one your mom used to stick where the sun don't shine to see if you had a fever - it is about 3/4 inch diameter and over a foot long, but it looks just like a giant fever thermometer. It covers the range from room temperature all the way up to way past boiling temp, so it is ideal for checking the accuracy of a car's gauge. When the engine is cool, take the radiator cap off and insert the thermometer, then start the engine. Watch the coolant flow - when it starts to move in the top of the radiator (the thermostat begins to open), pull the thermometer and read what it says - it should be somewhere around 160-170 for your 180 'stat. Now quickly look at your dash gauge and see what it reads. Remember that reading for future reference, and let the engine continue to run until the temperature stabilizes - it might take as much as a half hour. You can block off the air flow through the radiator to hurry things along. When your dash gauge gets up to the point you are worried about, quickly pull the thermometer and check it again -that will tell you what the temperature really is, within a degree or two.
To answer your question, if you have at least 30% anti-freeze, and if your radiator cap holds presssure, there will be no damage to the engine from running it at 220, but that is a bit high, and I think you are headed for some problems in the near future, especially in hot weather. With 30% anti-freeze, and a good 15 PSI cap, you're OK up to about 240 or 250, but that is really hotter than normal and you should have the radiator checked (step one) and if it still runs too hot, you'll probably have to have the block core plugs popped out to clean out the whole cooling system. Don't waste your money on flushing - it very seldom helps - it needs to be really taken apart and carefully cleaned out if it is running too hot.
BUT, make sure the gauge is telling you the truth before you start throwing money at the problem.
I drove a 65 A-100 van for almost 20 years (bought it new) and I did have to take the core plugs out of it and clean out the block when it was only 2 years old! I think they might have used bad coolant, or else left some crud in there when they built it.
Dick
