Quote:
Originally Posted by Shandysplace
With the AC off and at the steepest part of the climb our water temp topped out at 210 while 160 is the regular temp. Our Suburban is equipped with the factory towing package and a WDH.
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I hope that you don't consider 210* to be extreme. Your engine is designed to run @ 210*. In fact, it came from the factory with a 210* thermostat installed and your engine should run ~200 minimum. You may be doing more harm by running @160 than running @ 210.
I wouldn't be conserned about the temp until it reaches >225-235 (considering that you have the proper concentration of coolant in your radiator). High water temp isn't the real issue.
BOILING is what must be avoided. When the coolant boils, it will cause air pockets in the engine that may be super-heated to excess of 600* and stop the flow of coolant. That's when you have a real problem. A properly mixed coolant should have a boiling point of >280* minimum. Ethylene glycol has a boiling point of 370*.
Your engine is made up of a mixture of materials from cast iron block & heads to aluminum pistons and several other parts. All of these different metals have different expansion rates @ different temps. When they design a piston (for instance), they design it so that it is within tolerances @ a certain temp, in your case that is ~200*. When you run @ 160* the aluminum piston fits in the steel cylinder more loosely than it does @ 200*. The engine block has a lesser expansion than the pistons so the cylinders are not at the proper size @160* either. This farther exacerbates the problem.
Some mechanics think that they can resolve over-heating issues by installing a lower temp thermostat. This is not true. A lower temp thermo will merely not allow the engine to achieve it's normal operating temp when the air temp is cool. When it is hot out, either thermostat will be fully opened and allowing the same amount of coolant flow. This theory of a lower temp thermo is not only mis-guided, it is ultimately harmful.
ALWAYS stick with the factory recommended thermostat. In some States, the practice of installing a 160* thermo is illegal. If you take your vehicle to have a "Smog Check" it probably won't pass if the engine is under 195* because most emission control devises are designed to operate >195* and the pistons do not seal properly until >195*.
As for shutting off the AC......... it does slightly lower the stress on the engine but far more importantly, it lowers the air temp of the air that passes through the AC condenser that is used for cooling the radiator. NEVER turn the AC "down", that does not help and could actually increase the temperature at the AC condenser, thereby super heating the air that reaches the radiator, after it passes through the AC condenser. I would consider shutting off the AC @ ~230*. If it doesn't reach 230-235....there is no reason to suffer. I wouldn't even consider turning on the heater unless the temp reaches 250-260 and I've pulled off the road (with engine running and my family out of the vehicle) to let it cool down for awhile. Running the heater is pretty uncomfortable and only mildly helpful if the real stress has been removed.
Modern day engines can reach temps of 300* without damage. Agian........
BOILING is the enemy. It can help to have a spray bottle handy to spray water on the hot radiator to reduce the cooling time, with the engine running. NEVER remove a radiator cap on a hot radiator. If there is steam comming out, you have boiling. Shut the engine off, let it cool, then check the coolant level. Don't leave an engine running if it is steaming. You may have a vapor lock in the cooling system.