How To: Change Water Pump

After a leak that had been going on for a couple months, I decided I would go after changing out the water pump. I also wanted to flush out the entire coolant system as this hadn’t been done since I had the car. I ordered the new water pump from Jay Marks Toyota. About $60 for the entire kit that you see below ($80+ from local dealer). You can just purchase the water pump from your local autoparts store, but it will not come with the o-rings or the suction cover (that’s the left hand side of the pump below).

Note: You may want to change out your timing belt when doing the water pump (and vice versa), as removing the timing belt is only a few bolts away. (Albeit one of those bolts is the crank pulley’s which can be a bear to get loose.) However, I chose not to do this, as mine was just done 30k miles ago. Believe me, the timing belt does get in the way, especially when installing the new pump, but it is definitely doable without removing the timing belt.


Here’s a couple pics of the new pump part #16100-19115:

Here’s what else I bought for this project (2gal Toyota coolant, Prestone Super Flush, Permatex Ultra Copper & Permatex Water pump and Thermostat Housing Gasket Maker). Not pictured, I also purchased new alternator and AC belts, since you need to remove these too.



Draining the old fluid:

First off, drain out as much old coolant as you can. Jack up the back of the car higher than the front, remove the front-most underbody cover (seven 10mm bolts), and remove either the drain bolts shown here, or use the draincock on the bottom of the radiator. I chose to use these 2 drain bolts, because my radiator draincock was plugged. Make sure to remove the radiator cap and also loosen the drain cock on the top of the radiator. This will allow air to vent into the pipes, allowing the coolant to drain out easier.

Here’s what came out. Nice and brown huh? They say this is from mixing the Toyota red coolant with the typical Prestone green stuff. Make sure to dispose of this stuff properly. Ya wouldn’t want to kill any of your neighbors pets now would ya???


You can chose one of two routes here. Either flush out the system now, or go ahead and change out the pump. I decided to change out the pump next. Here’s how to go about that:

Removal of old water pump

1) Remove the 2 hoses circled below and remove the coolant reservoir by pulling it straight up.


2) To give you ‘plenty’ of room to get to the water pump, remove the radiator cap mounting tube. Do this by removing the spring clips (shown in the square box on the right and pointed to by the red arrow) clamping the hose to this plastic tube. Remove the two 10mm bolts shown in the green circles. Then remove the hose going from the radiator cap to the engine, by removing the spring cliip contained in the left red square.


Here’s the result of the above removal. You can start to see the water pump now…


And here’s the parts that you just removed:


3) Now, disconnect the 3 different wires (black, green, and blue connectors) that will be in your way and tuck them away someplace..

4) The next thing you should do is loosen (not remove) the water pump pulley bolts (four 10mm bolts shown in the red square). This is alot easier to do while the belt is still in place.


To get to all the bolts on the pump pulley you will have to turn the crank pulley. Do this by using a 17mm socket on the below circled bolt. To make this easier to turn it’s best to remove the spark plugs. (I didn’t do this however…) You have to remove the bottom engine cover (about seven 10mm bolts) to get to this easier.


4) Remove the alternator and it’s adjustor bracket. If you have not done this before, refer to my alternator write-up for the removal process. (some of the below steps show the alternator in the pics still. I didn’t remove it till I had to, but I would recommend doing it now.

5) Remove the water pump pulley bolts that you loosened earlier and remove the pulley.

6) Remove the ‘coolant inlet housing’ located in the red square box (two 10mm bolts from the front and one 10mm bolt that needs to be removed from under the car).


7) Remove timing belt cover #3. Here’s a pics of the cover removed to give you an idea of where all the 10mm bolts are located.

Here’s a pic of the timing belt cover #3 removed.


8) If you have AC, remove the AC idle pulley. The below picture already has the belts off but it should give you an idea of where the pulley is located, between and above the crank and AC pulleys. Use a 14mm box end wrench to remove the nut from the pulley.

The red circle below shows where the 15mm bolt (it’s a real long one) that holds the idle pulley bolt in place. Remove this bolt. The idle pulley should now be free, so remove it and the two belts.

Here’s the idle pulley after removal:


9) There are only 2 bolts holding timing cover #2 on, since #3 is out. Get to them from below the car, and here are pics of where they are located:

Here’s the one near the rear of the car, 10mm. (Ignore the fact that the new water pump is already in, I took the pics out of order.)

And here’s the one on the other side of the crank. It’s right behind the idle pulley bracket and is a pain to get to. I found a 10mm offset boxed wrench to do the job (luckily I had one).

Here’s a couple pics of the two removed timing covers. The one on the right shows how they are assembled when on the car. Be careful when removing timing cover #2, as the needle on the timing belt idle pulley comes out the hole in the bottom left of the cover. It’s actually a plug that surrounds this needle, that you can remove if you want/need to.

This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.

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