It's listed as being in the right rear of the engine block. For a simple maintenance drain and fill it is not customary to remove the block drain plug. You won't get very much coolant out that didn't already come out the radiator. For that matter, we also rarely use the petcock in the radiator. Most of them are plastic now and are screwed into plastic radiator tanks. It's all too common for the rubber o-ring's sealing surface to crack when the plug is reinstalled, then there's a drip about once every five seconds. The only fix for that is to replace the radiator. Instead, we typically remove one end of the lower radiator hose. That causes more of a mess, but when we have to charge by the hour, it's much faster.
If you want to be real thorough, remove one of the heater hoses at the engine, then run water through it from a garden hose. That will flush out the heater core and the coolant that has puddled in the engine block. Next, I like to disconnect the small rubber hose going to the reservoir, from the radiator, and let it hang down. Run water into the reservoir until it's overfull. I use a pressure washer for this step. The water will run out the hose and syphon the reservoir empty. Do that a second time, then leave it empty and reconnect the hose.
After that flushing, you can expect to have between a half gallon and a gallon of water stuck in the block and heater core. Start by adding a gallon of straight antifreeze, then alternate, half gallon of water, then a half gallon of antifreeze until the radiator is full. Four-cylinder engines usually have a bleeder screw on or near the thermostat housing. Open that while filling the system. For V-6 and V-8 engines, check for a bleeder screw, but there usually is no need for one.
Run the engine to mix the coolant and bleed any air out at the bleeder screw. After a period of mixing, check the freeze point. It should be as close as possible to minus 35 degrees F. Colder is not better. Due to the chemical reaction, the freeze point actually goes higher as the percentage of antifreeze increases. That is not how it shows up on most testers. They work by comparing the weight of the coolant in relation to the weight of straight water. Straight antifreeze is heavier than water so the floats in most testers will be very high, indicating a real low freeze point, often as low as minus 70 degrees F., but straight antifreeze actually starts to turn to slush at around minus 10 degrees. It's when antifreeze and water are combined in the right percentages that the freeze point is at its lowest temperature.
Once you know the freeze point, you can adjust it by adding either water or antifreeze into the reservoir. After that, you'll need to run it through a number of warm-up / cool-down cycles to mix in what you added, so don't bother rechecking the freeze point for at least a few days. We have a feel for how much the freeze point will change for a given amount of antifreeze, so there's no need to come back days later to have it rechecked.
I do have one word of warning when it comes to flushing heater cores. Antifreeze is alcohol and will always be alcohol, but it's the additives in it that wear out in about two years. That includes seal conditioners, anti-foaming agents, and most importantly, corrosion inhibitors. When this maintenance is ignored, acids start to build up in the coolant that attack metal parts, especially the aluminum heater core and radiator tubes. It's real common to have casting sand stuck in the engine block from the factory. That sand breaks free and collects in the heater core, sometimes plugging a leak that has developed. That sand gets washed out the first time the heater core is flushed. If that first time is now, it is possible to clear it away to expose the corroded hole and have a leak that wasn't there before. This is less likely to be a problem if the coolant was replaced regularly in the past.
You may find these articles of interest too:
https://www.2carpros.com/articles/engine-coolant-59420607
https://www.2carpros.com/articles/engine-cooling-system
https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars
Please keep me updated on your progress.
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Saturday, July 2nd, 2022 AT 2:03 PM
