arlen said:
http://garage.grumpysperformance.com/index.php?threads/how-radiator-caps-work.7718/
210F is hardly a cause for concern, but if your determined reduce the operational temps, to stay in the 180F temp range because you state its not over heating at lower travel speeds, even during extended trips as long as the vehicle speeds are low, increased speed and related factors seem suspect.
when temp sensors don,t agree with what you think the engine temps are then the sensors obviously either measuring a different area with a different temp OR the sensor or gauge is defective, to find which is true youll need to verify with a reliable third measuring tool, like a quality IR temp gun, and measure the sensors with a muliti meter
infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors , without verified facts your guessing.
this is the most consistently accurate I.R temp gun I've used for testing[/img]
http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN
logically the vehicle would over heat faster at lower speeds due to lower air flow thru the radiator at lower speeds,especially if it was a block or heads interior coolant passages that were partially blocked.
thus you should look at what changes occur during higher travel speeds that are not the same at lower speeds.
the first thing that jumps to my mind is the question of if your running an automatic transmission, as higher speeds generate higher coolant flow rates and higher trans fluid temps?
have someone raise and hold the engine rpms up at lets say 3500rpm while you carefully inspect the lower radiator hose, in some cases higher engine speeds cause them to suck partially closed, restricting coolant flow, normally cured by using a lower coolant hose with internal structural spring re-enforcement, that prevents collapse under vacuum
next what oil pan are you using? a low capacity oil pan would allow the engine oil to heat and not cool to a much greater extent at higher engine speeds, so if your running less than a 6 quart oil pan Id consider swapping to a baffled oil pan of 7-8 quart capacity or adding a combination oil and trans fluid cooler to remove heat from those fluids.
you might also find that higher engine speeds cause the engines ignition to advance to the point the engine runs hot where at lower speeds the ignition never reaches that point in the advance curve,
or you might find a restricted exhaust causes the engine to over heat as the higher engine speeds, naturally produce a higher volume of exhaust gasses.
theres also the possibility your carburetor or injection tends to run leaner at higher engine speeds so tuning the car and reading spark plugs might help, youll now only after checking carefully.
you might also want to check your oil level, an use a long oil filter that holds more oil and use a bit of (WATER WETTER) in the anti freeze coolant.
so like in locating and solving most automotive problems, you will need to logically isolate the potential cause, and test to find out if it is the cause, and then cure the problem, once youve proved the cause, don,t over look simple things like belt tension,
or silly mistakes like mistakenly installing a water pump designed for the opposite rotation direction
ONLY US OLD GEEZERS WOULD MORE THAN LIKELY SEE A CRICKET GAUGE AND EVEN RECOGNIZE WHAT ITS USED FOR
related info
http://www.cjponyparts.com/lower-radiat ... 3/p/HW769/
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