Friday, February 26, 2010

DIY Coolant Flush & Maintenance Corolla 93 - 97

This DIY is for replacing the radiator hoses , thermostat and flushing your coolant . Especially if your hoses been on you car for at least 5 yrs and you haven't flushed your system out or you haven't been using proper coolant and using water . Plus check your heater hoses to .

First you should remove the distributor cap so that you can have more room to get to the thermostat . You do not have to remove the wires .

After that then you can remove the air filter box completely . While you have this off it's best that you clean the inside before putting this air filter box back on .

Then you put a oil pan under the radiator drain plug and then unscrew the plug and let the radiator coolant drain into the pan .

Then remove the pan, Do not close the drain plug yet . Now if you weren't gonna replace the hoses or thermostat then you would put your water hose in the radiator and start your car and put the heat on inside the car and flush the whole system out until you see clear water flowing out the drain plug . The reason you have the car running is so that the thermostat can open up and the reason you have the heater on is so that the heater core is opened up and you can flush the heater core at the same time . Once you see clear water draining then shut your vehicle off and your hose and just let the rest of the water run out completely . Then see below on how to fill up your radiator .

Now with your pliers you then remove the hose clamps around the upper and lower hoses . Some people might have the one's with the screw driver then you would unscrew them . Some people replace the OEM hose clamps to the screw one's and some people reuse the OEM clamps . In this case I will reuse the OEM clamps cause there not rusted and they look fairly new .

To get to the bottom hose clamp for the lower hose you have to remove the water shield first . It's like three bolts holding it . You do not have to remove it completely just unbolt it enough to see the bottom hose clamp .

Then you can remove the thermostat housing . First you have to unplug the temperature switch wire . Then with a 10mm you can remove the two nuts . Be careful don't lose these nuts .

Once you remove the thermostat housing it is important to remember how the thermostat sits . The deep part goes inside the block . You can reuse the rubber gasket for your new thermostat but inspect first . As long as the gasket isn't pinched or cracked you can reuse it . That's why when they sell you the new thermostat it doesn't come with the gasket .

Since you remove the hoses now you can put your water hose in the upper part and flush out the block . Do not run your car for this . Flush until you see clear water coming out of the bottom of the block . Then of course you flush out your radiator . Try not to wet your distributor since the cap is off and the inside will be exposed .

Then with your mini wire brush you can get any corrosion that is around the thermostat housing and around the all the areas that the hoses will be replaced .

Some people don't and you really don't have to but I put just a tiny bit of water pump/thermostat silicone only on the housing part . Make sure the thermostat area is dry before putting your housing back on . Very important when you tighten the nut for the housing that you DO NOT OVER TIGHTEN . This is only hand tight . The stud will break very easily if you over tighten .

Then with a pack of hose grease that they sell in the auto parts store you put some on the inside of the hoses you are replacing . This I recommend because the next time you replace your radiator hose or ever have to take it off to work on something else it will be so much easier to remove your hoses and your hoses will not stick around the areas you clamp . Then you can put your distributor cap back on and air filter box .

I use water wetter because you can use this in any type of climate or vehicle and in the summer when you use your A/C or if you run hotter spark plugs in your car this product is awesome . This is product is used for all water cooled vehicles . This will make your car run up to 20% cooler , improves heat transfer and lubricates your water pump seals and reduces rust . Can be used with all antifreeze coolants .

Once you put all your hoses on and then you tighten up the radiator drain plug . Then you can add your water wetter in first , Then your antifreeze coolant you can either buy the premix 50/50 or you can buy the one that you mix yourself with water . Do not pour straight antifreeze coolant into your radiator . Best if you have another jug or bucket when you mix the coolant with the water . Then as you are pouring your antifreeze coolant turn your vehicle on and put the heater on and keep and eye on the opening of the radiator for bubbles . Run the car for awhile and keep refilling until you see no more bubbles and the radiator is full . With the rest of your coolant put some in the over flow tank.

Then with in a few days of driving your vehicle check the over flow to see if you need to add any more coolant in your over flow tank . Now you are ready for long distance driving with out over heating or hoses bursting .


  1. Would this work on a 98-02 corolla?

  2. The location of the 98 - 02 thermostat is different . But the rest will work .

  3. Thanks a bunch! My 96 corolla's thermostat been fluctuating and also i think there's a leak somewhere. With this im gonna replace the hoses my self! thanks!

  4. Hi, I own a Corolla DX AT 1800cc 1993, it recently started to spill coolant after a few minutes of driving, all the radiator coolant get out through the overflow tank, when I turn it off I can hear the coolant boiling in the overflow tank...

    What could be the problem? Thanks in advance!

  5. Arturo, did you ever find a good fix for the problem you mentioned in September? I have nearly identical issues here with a 95 Corolla with a 1331cc 4-cylinder engine. I can hear water boiling while driving, and there is a not-very-slow water leak from the engine area (not radiator or hoses).

  6. Since this still comes as the very first result on google I will add that you should never run tap water in any engine, especially ones that have an aluminum head on a cast iron block like many Corollas. Use distilled water or de-ionized water. Wal-Mart has distilled water for 88 cents per gallon as of 2016.

    I had a 95 Corolla that started blowing water out of the overflow after 10 months of driving. It ended up having a warped head. Napa charged $42 to resurface the head. The engine block was warped slightly but not as bad as the head so I went over it with a piece of 80 grit sand paper and a block of wood until it was less than .0015" from flat with an $80 N.I.S.T. certified straight edge and a feeler gauge.

    The cooling system capacity on both the 1.6L and 1.8L is 6 quarts. According to the Haynes repair manual. That's about 5.67812 liters.

    I have now performed necromancy upon this thread and made it my un-dead servant. :P

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  8. This was very informative. If only I found this sooner, before I changed my radiator fluid and replaced only one hose. I'm just a girl so give me a break. Now I'll go back and do it your way.
    Thanks for your step-by-step pictures and directions. I'm saving this page for future use.
    I'm ready now to do my friends cars. . . . . . Don't run and hide??