97 Corolla flush

I've got a 9797 Corolla CE with the 1.6L in it. Antifreeze is horrible and needs a flush and change. How do I drain it all out? When I put new fluid in, I assume that I use the radiator cap fill. At 169,000 miles and no previous coolant change, should I just flush it or use a cleaner?

Also, regular green stuff or Toyota Red stuff?

The coolant drain plug is a plastic butterfly-looking capscrew at the base of the radiator on the passenger side pointing toward the engine -- the lower under shield should have an access hole that allows access from below without removing the shield.

You can go though the whole flush procedure with special chemicals, but after draining you can fill with plain water and run the engine (with the heater control temp on HOT to also flush the heater core) until it reaches operating temp, then let it cool and drain the water -- you would do this until the coolant/water drains pretty clearly without any stuff in it -- then refill with either the green or red stuff. As far as I know the two coolants mix without issue.

OK. Should I use a back-flush kit? Also, when I drain the fluid, does most of it come out of the block also? About how much might stay in the block?

I would use Toyota red antifreeze only (do search on Antifreeze or check the FAQ section). Also look for a small screw in plug on the engine block for draining the block. Put antiseez on the plug before reinstalling. On the 1.8 the plug is near the oil filter. Don't know where it would be on the 1.6. Drain both the radiator and block. Refill with water, warm it up. Drain again and refill with 50/50 mix of antifreeze. You can buy either premixed or concentrated antifreeze from your Toyota dealer.

I don't see the need for a flush kit, its just a place for future leaks.

Be very careful about removimg the drain plug on the block. I wouldn't do it unless I absolutely had to. If you strip or break it off you are in very big trouble. Back flush the system and add distilled water with antifreeze. If it is as bad as you say it is I would change it more often.

OK. Is there any other way to get the rest of the water out of the block? Where can I locate the thermostat on this thing? 1.6L

You shouldn't stress yourself out about totally draining the coolant so that the engine is bone dry. A totally empty water jacket in the block will certainly leave air pockets when you try to refill it -- air in the collant will cause you more problems because air does not absorb heat as well as any "old" coolant that may remain -- overheating will be your result.

Fill and drain, fill and drain.... it's the best way.

In reply to the last post, thanks. So when I d the complete back flush, should I just put the pure anti-freeze in the radiator to give me the 50/50? This is non-diluted stuff that I have.

Don't get too scientific -- 50/50 is just a general guide.

100% water would provide better cooling, but water freezes solid at 32F (0C) and will not lubricate the water pump and cause rust to form in the engine's cast iron parts.

100% Anti-freeze would not remove heat from the engine as efficiently as just water (but it would still be better than nothing or air), but you could live in Antarctica without worry of the coolant freezing.

Anyway, the cooling system capacity for the 1997 Corolla 1.6L 4AFE is said to be 6.2 quarts -- Antifreeze comes by the gallon -- 4 quarts -- so if you ran 100% water through the system once or twice, you would add the full gallon of antifreeze -- then fill the empty container with water, and top it off. Then, if you need to add coolant, use the plain water.

We usually do this before Winter for this reason -- for the wintertime, a 60/40 mix is ok as a start as it increases the freeze protection and water pump lubrication.

If you want to be really scientific, you can buy a tester at your local parts place -- it looks like a turkey baster or an eye dropper with candy inside -- the candy floats or sinks in the tube based on the "quality" of the coolant mix it samples.