Where is the plug to drain the engine block?

Asked by Jun 16, 2007 at 04:22 PM about the 1988 Mazda 626

Question type: Maintenance & Repair

I am trying to drain the engine coolant and cannot find the plug.  Chilton does not show where it is.

5 Answers


It should be on the right side of the engine. Are you sure Chilton doesn't show you how to drain the engine coolant? That is the type of job those manuals are great for.

2 of 2 people found this helpful.

Previous question and answer are vague. The heading of the question indicates the one asking is referring to the "engine block coolant drain plug" but the answer indicates that the person answering is probably referring to the "radiator coolant drain plug." According to one online comment I found, all gasoline engines have both "engine block coolant" and a drain plug for it, and "radiator coolant" and a drain plug for the radiator. When draining the radiator, most people probably do not drain the "engine block coolant" using the engine block coolant drain plug. They just drain the radiator coolant using the radiator drain plug. The engine coolant is very important to drain, flush and refill properly using the manufacturer's recommended engine block coolant. If the engine block coolant is just using the same coolant as the radiator, the point of draining the engine block coolant is to make sure that residues in the engine block are properly flushed out at the same time as the radiator itself is flushed and reloaded. If not, I think the engine coolant residues will eventually doom the engine; manufacturers probably know this, and keep it a semi-secret, hoping people have to buy a new car in a few years. If you look online for the coolant and radiator flush procedure, about 95 percent of the advice tells only about how to flush the radiator, but nothing about flushing the engine block coolant, or at least draining the engine block coolant to reduce the gunk buildup in the engine block cooling sections. If someone knows more clearly please comment. Thank you.

2 of 2 people found this helpful.

I have two manuals for Mazda 323 1994. Both are very poorly indexed and neither shows the location of the engine block coolant drain plug. The radiator coolant drain plug is easy to find. But I am not sure where the engine block coolant drain plug is located. There would be no reason not to tell where this is, at least in the manuals, but it should also be clearly marked (in English, when sold in an English speaking country). Or it could be marked with some sort of number or acronym. Car manuals are always for a range of roughly similar vehicles. How lucky one is if he or she owns the car that is primarily featured in one of these manuals. If not, one must sort of wing it in almost every task, and this is not a healthy situation when one is either not highly skilled, not working with a full deck, or both.

1 of 1 people found this helpful.

Don't bother trying to drain the block. Put the hose back on, fill it with hose water, run the engine to mix it up and drain it. Do that a couple of times to flush the old coolant out. When your ready to fill the system, pour in the required amount of straight antifreeze. Top off with distilled water and it will mix in the engine. You can top off if needed with water.

1 of 1 people found this helpful.

Jay above is correct: a lot of gunk will collect at the bottom of the block. The problema is 95% of the engines do NOT come with a properly located block drain! I have performed a flush on my car, a Dodge 2.4L engine, and found that even when using the specified coolant (Chrysler's HOAT 5-Year and demineralized water), there were heavy deposits visible when removing the so called "expansión plug that is locatedbehind the starter motor. And the deposits remained even after using detergent followed by citric acid and neutralizing. Commercial "Radiator flushes" did NOT performed a noticeable cleaning. I had to remove that "freeze" plug to actually see the deposits. But the hole where the "freeze" plug is, in located quite above the bottom of the cooling jacket inside the block, thus I needed to use a wet and dry vacuum to aspirate the remaining dirty coolant from the block bottom, but learned that even using the recommended coolant and pure water, there will be deposits hindering cooling. Amclausssen.

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