Toyota Tacoma

Water Pump & Thermostat Replacement
Information about Timing Belt replacement

Vehicle Information: 1996 Toyota Tacoma, manual transmission, 4WD 3.4L V6, 84,000 miles
This write-up is about a Water Pump Replacement ONLY and not a Timing Belt replacement. This write-up is a reference tool only. USE AT YOUR OWN RISK!!  I do not have specific instructions on how to complete certain tasks, but only helpful pictures and tips for your own removal and installation.  A timing belt replacement is very similar to a water pump replacement and you can use this write-up as another reference tool - however - it is possible to install a water pump without removing certain items as is required in a timing belt replacement.  I have included some diagrams from our Toyota Service Manual and Haynes Manual about the timing belt replacement for your reference - please click HERE When conducting this install - we followed the Toyota Service Manual until we felt we needed to 'stray' from their instructions and made our own decisions.  The Toyota Service Manual and the Haynes manual suggest removing more equipment than necessary. We did not feel it was necessary to remove everything!  You may need to refer to the Toyota Service Manual scans to learn the 'names' of each parts as they are listed below.  Any images you see can be 'clicked' on for a bigger picture. If you have any questions about this write-up visit:

Troubleshooting: I purchased my truck with 59,000 miles on it and requested the dealer (Saturn Dealer) replace the timing belt as part of the sales agreement. They did not replace the water pump at the same time (highly recommended). At around the 70,000 mile range I began to notice my overflow tank was missing coolant. For about a year, I continued to watch this and refill the tank as necessary. At 84,000 miles, I began to notice coolant dripping on the frame and other areas. This is when I began to look more closely at where the coolant was coming from. Since the water pump was not replaced at all - I automatically realized I needed to replace it. The actual pump itself was fully functional - however, the seal had deteriorated causing the coolant leaks.

Parts Needed & Other Information: Toyota Water Pump Part # 16100-69395.  Toyota Thermostat Part # 90916-03075. This part includes sensor and replacement gasket.  No replacement nuts.  We ordered it from Conicelli Toyota Make sure when ordering any parts that they are specific to YOUR application.

1) Remove Skid Plate
2) Disconnect the Negative battery cable. 
3) Drain fluid out of the radiator - it may drip for a long time.

4) Remove Upper Radiator hose. Be sure to stuff paper towels (or other type of towel) in both holes. This will prevent debris from getting inside. 
5) Remove all accessory belts (A/C belt, Steering pump belt, and Alternator belt).
6) Remove Fan Shroud

NOTE: After removing the fan shroud, my husband cut a piece of cardboard and inserted it over the radiator. This would help protect the radiator while we worked in that area. This picture shows the cardboard in place, all accessory belts and upper radiator hose removed.



7) Remove Fan from Fluid Coupling (part with cooling fins on it) as seen here.


Remove Fan
8) Remove Timing Belt Cover (as seen to the left).
No Fan Cover

9) Remove Power Steering Bracket.
Your power steering pump should be slightly loose from when you removed your belt.  Do not totally disconnect the power steering pump. Only remove the bracket that is seen below. This bracket is attached to the Fan and pulley bracket assembly.


Power Steering Bracket

10) Remove Fan Bracket - The Fan Bracket attaches the fluid coupling and pulley assembly to the engine block. 
We found it easier to remove the fan bracket and lift the entire assembly out of the vehicle instead of unbolting each unit separately. Besides that, we were unable to get a good grip on the 'free spinning' shaft to get the bolts loose on the fluid coupling.  The fan clutch would not allow us to do it. This is a picture of the entire fan bracket assembly removed from the vehicle.  It has the fluid coupling (top), pulley assembly (middle) and the actual fan bracket (bottom). 

Fan Bracket

Make sure the vehicle is in NEUTRAL and parking brake is ON before doing this next step. You are about to do one of the most intimidating things to your truck. You're going to manually crank the engine!!!   
The top two pulleys are called Camshaft Pulleys.
The lower pulley is called the Crankshaft Pulley.
The Camshaft pulleys (upper) will have little notches on each pulley.  Take notice to where these notches are.  The (lower) Crankshaft Pulley will also have a notch in it.
11) Find yourself the proper sized socket for the nut on the Crankshaft pulley (preferably 1/2" drive) and slowly turn the crankshaft (lower) pulley CLOCKWISE ONLY!!!! 
Turn the crankshaft clockwise until the little notch is lined up with the ZERO as seen below.  This will set the timing to ZERO - setting Cylinder #1 at top dead center (TDC).

Timing marks

Take notice to the upper pulleys, the notches should be positioned similar to each other and near the top.

For our water pump installation, we will not be removing the timing belt completely. Because of this, we need to mark the timing belt and each of the camshaft pulleys with a magic marker (or other clearly visible writing object). Mark a straight line across both the belt and the pulley to ensure a straight line crosses each. This will ensure we get the timing belt teeth back on the pulleys in the exact teeth position they were before we removed it.

Timing Marks
12) Find a piece of wood approximately 1" thick and about 5" X 8" long (I'm guessing). Or, if you have some cargo straps......keep them aside and ready for the next step.
Wood Supports
13) If you have air conditioning - at this moment, you will wish you didn't! Take a cargo strap and wrap it underneath the A/C compressor pulley and then around the steering pump. Tie it down loosely. This cargo strap will help support the A/C compressor(safety precaution)as seen below. The piece of wood that I mentioned above, will be wedged underneath the compressor and the cross member. This will allow the compressor to rest on the wood without putting stress on the A/C lines. Tie Straps

14) Now that you have the A/C compressor supported with straps & wood, remove the 4 bolts that hold the A/C compressor to the bracket. Carefully slide the A/C compressor & wooden support over as far as you can against the frame. You'll need all the room you can get in-between the compressor and the A/C bracket.

15) Remove the A/C bracket from the vehicle - there are 2 bolts hidden in-between the A/C compressor and the bracket. This is the main reason why you needed to remove the A/C compressor. As seen below, a picture of the A/C bracket. NOTE: We cleaned a LOT of mud and dirt off of this bracket. The mud was caked inside!!!

16) At this time, you'll want to focus your attention on the Timing Belt tensioner as seen to the left (arrows). The long arrow on the right is pointing to the tensioner pulley. The pulley is a hydraulic tensioner and has a reservoir tube where the fluid is stored (center arrow bottom). We did not have any special tools or equipment on how to release the pressure on this pulley so we were forced to come up with our own way of doing this. If you'll look at the outer arrows (bottom section), these are the bolts that hold the tensioner in place. Tensioner
17) Loosen these bolts a little bit at a time - rotating back and forth between the two bolts. You will not remove these bolts nor will you remove the entire tensioner assembly. As you loosen the bolts, the hydraulic assembly will begin to separate itself from the engine block/mounting area. Each time you loosen both bolts, check the tension on the timing belt. You want to get the tensioner at its max position without removing the bolts. Just enough allow you to remove the upper pulley. As seen to the left, a picture of the assembly as it has separated from the mounting point. You shouldn't need to loosen it anymore than this. Tensioner

18) When the belt is just slack enough - focus your attention on the upper (central pulley) as seen in the picture below. Remove this pulley.


Upper Pully

19) Carefully remove the timing belt from the camshaft pulleys. Be very careful to ensure the teeth do not slip from the crankshaft pulley below. We used a tie-wrap and strapped the belt aside to prevent it from falling or getting in our way. To the left is a picture of the old water pump. The small pulley in the center of the picture is the water pump pulley (drives the pump).

Old Pump

20) Remove the lower radiator hose (make sure you have a bucket to catch any excess antifreeze).

21) Disconnect the Thermostat housing. Be careful when removing, the thermostat is inside. Make a mental note of how the thermostat is installed (spring side goes into the block).

22) Disconnect the rubber hose that is on the water pump (right side). This hose will still have fluid inside. Try not to loose any of this fluid. When you remove it -point the end of the hose upward to prevent spillage.

23) Grab some old towels or paper towels and plug up the area that the timing belt goes into. This is to prevent any dirt falling down inside and interfering with the crankshaft pulley. If you've done a lot of muddin, you will be making a mess! DO NOT get any fluids, or oil on the timing belt.

24) At this time, you may want to disconnect the oil dipstick bracket off the alternator. Be careful not to bend or kink.

25) Unbolt all 7 bolts on the water pump. Carefully maneuver (finesse) the water pump out of the vehicle. You may need to shift the dipstick over slightly to get the water pump completely out.

26) You'll want to take more paper towels and plug up all those holes in the engine block. You do not want to get any dirt inside.

Pump Removed

27) Clean all the gasket material off the engine block. Clean all the surrounding areas. As seen in the picture, I'm using a Dremel tool with a wire brush end to clean the surfaces. The surfaces need to be nice and smooth and clean before applying the new water pump.


28) After the surfaces have been cleaned thoroughly, you can remove the paper towels from the holes in the engine block.

29) At this time - you will need to prep your new water pump. For a 1996 Tacoma with a V6 - the Water pump part # is:16100-69395. We also replaced the thermostat which is part #: 90916-03075. We bought our water pump from Conicelli Toyota Internet sales for $87. I didn't get any pictures of the new pump so I'll bless you with pictures of the old muddy one just to give you an idea of what it looks like.

Pump Front

The picture on the RIGHT has the old thermostat in place. As you can see, the mounting surfaces of the pump have a small ridge. This is where you will apply gasket material on the new (and clean) pump. We used Permatex Ultra Blue Sensor-safe RTV Silicone Gasket maker. You will need a similar gasket material for this application. Make sure you read the directions and follow them carefully.


Pump Back

30) Carefully install the water pump in the same manor that you removed it. Be careful not to bump or accidentally remove any of the gasket material off the pump or you could encounter leaks. Only hand tighten the bolts initially - do not over tighten. According to our Toyota Tacoma service manual, the torque specifications on the bolts are 14 ft/lbs.

Here is a picture of the new water pump, thermostat, and hoses installed.

New Pump

31) The next and last critical thing to do at this point is double check your work. Make sure you installed the small hose on the side of the water pump. Double check all your bolts and reinstall your oil dipstick bracket.

32) Carefully take the timing belt and wrap it around both camshaft pulleys - aligning the marks on the belt with the lines on the camshaft pulleys. Again, this ensures the teeth are in the exact placement as before. Carefully install the center pulley. Tighten up the tensioner bolts same as you loosened them - little bit at a time rotating back-n-forth.

The rest is simple - you can finish it on your own.

We let our truck sit for about 24 hours before we started the engine. This is only to ensure the gasket material 'cures' fully before exposing it to moisture.

Comments? We found having a 'ratcheting' closed end wrench set was perfect for those tight areas. Because we replaced the water pump and emptied the hoses of all fluids - we thought there might be some 'purging' procedure to ensure fluids are in the engine block. We also thought - the thermostat is currently dry and wouldn't be able to OPEN or cycle the fluids when necessary. But....have no fear. All you need to do is start the engine and let it idle for a while until you can feel the upper radiator hose get hot. At that point, you'll know the fluids have cycled within the system. A local mechanic told us it would be a good idea to get the water pump fan and bearings wet with radiator fluid prior to installation. But that's your decision if you want to do that or not. We didn't - and everything seems fine.

Hope this helps!

That's It!!
Please - Be Safe - Be Patient - and Good Luck!