2004 Isuzu NPR-HD V8 6.0L without Water Pump Casting # 12562459 Engine Water Pump TRQ WPA07325

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In this video, we're going to be working with our 2002 Chevy Suburban. We're going to show you how to remove and replace the water pump on your 5.3L V8.

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Here are the items you'll need for this repair.

Remove the coolant cap before draining your coolant or lowering the level, as with the cap off, air can flow through and let the coolant drain faster.

Raise and support your vehicle. We're using a lift to make it easier to show you guys what's going on at home, but this job can easily be done in the driveway or your garage with a jack and jack stands. Place a drain bucket under the front driver's side of your radiator. There's actually a little drain hose tucked up here nice and neat. We're going to flip that down and hold it over our drain bucket while we loosen the pet cock and allow the radiator to drain. Loosen the hose clamp just after the mass airflow sensor. This is going to be the second one back from your air box. We'll do this using a flat blade screwdriver.

Wiggle and twist the boot to release it from the mass airflow sensor. You may need to use your screwdriver to help kind of peel it back here. These tend to get stuck on pretty good. We'll also remove the one at the throttle body. We'll need to disconnect the hoses from their clamps here. You can either try prying it out there, or there's also a little clamp at the bottom here that you should be able to compress. Pop loose with a flat blade, and remove the intake runner from the vehicle. Pop this hose clamp out with a flat blade screwdriver, and remove the hose.

Remove the two 10mm screws at the top of the fan shroud with a 10mm socket and ratchet. We're going to use our trim tool from 1AAuto to pop these up. You can also do it with a flat blade screwdrivers or a pair of side cutters. You don't have to remove the center pin fully, just pop it up, and wiggle the rest of the pin out. There's one at the back on each side like you saw there, and then another one here, up by the radiator. That one also has a twin on the opposite side. Pull back, and lift up the upper radiator shroud.

There are a few methods for reaming the large nut securing the fan clutch onto the water pump. Some of these methods include using air hammers, putting a wrench or an adjustable wrench on there and hitting it with a hammer. We haven't had luck with any of these methods, so we're going to use a C-clamp with a rubber boot on the clamp. Clamp the serpentine belt together and onto the water pump pulley to try to keep it from turning. Now, that rubber end really shouldn't damage the belt. We're going to replace our belt anyway while we do our water pump so we're not worried about it anyway. We also haven't had any luck with striking our adjustable wrench, so we're actually going to put a piece of pipe over it and just try to leverage it off there nice and easy. You should be able to spin the rest off nice and easy. We'll now remove our C-clamp.

Before removing your serpentine belt, make sure your vehicle has a belt path diagram under the hood somewhere. If this is missing or faded, you can just draw another one onto the plastic with something like a paint marker. Using a 15mm wrench on the tensioner, rotate the nut clockwise to slack the belt. Pop the belt off of whatever pulley is easiest for you to reach. Let the tension off the pulley and remove your serpentine belt.

You need a 15mm socket, ratchet, and extension to remove the three 15mm bolts on the tensioner bracket. Using a pair of pliers, and we do have a drain bucket setup underneath our vehicle here. Release the clamp on the lower radiator hose at the thermostat housing and move it back. I like to wiggle the hoses or twist 'em to try to get them to release. We'll just tuck that hose up and out of the way. Remove the two 10mm bolts on the thermostat housing. Do this with a 10mm socket and ratchet. We're just going to allow that to hang and drain out in a more controlled fashion. Remove the thermostat and housing from the vehicle. Remove the clamps for the heater core hoses.

Remove them from the water pump as well. Disconnect the smaller hose from the upper radiator hose. Compress the clamp with a pair of pliers. Wiggle the upper radiator hose off of the water pump. You can remove the six 10mm bolts, three on each side of the actual water pump pulley with a 10mm socket, ratchet, and extension. Just make sure when you remove these bolts that you have some method of keeping them organized. These particular ones appear to be all the same length, but with any hardware going into the engine, you'll want to make sure that they all go back and exactly the same place, because a bolt being too long or too short could cause damage or failure.

Once the last bolt is out, and again, we do still have a drain bucket under our vehicle because coolant does pool in the system in certain places where it won't drain. We can remove our water pump from the vehicle, and I'm just going to let it drain down into the pan that we have under the truck. Somehow, the old paper gaskets on our water pump came off really clean. This is not a normal scenario at all, however, if you remove yours and you still have some chunks of the old paper gaskets stuck on there, be sure to scrape 'em off with a razor blade. We'll then dry the surfaces and wipe 'em off with a clean rag or paper towel and probably some brake parts cleaner, just to make sure that everything's good and we get a nice, good seal on our new water pump.

Here, we have our old water pump thermostat that we removed from our vehicle and our new parts from 1AAuto.com. As you can see, these parts are exactly the same, with the same six bolt mounting locations for our water pump to the engine block, a new pulley with the same threads to reinstall our fan and clutch. It even comes as a kit with a new thermostat, which is actually kind of cool on these vehicles. It is part of the housing, so that'll just bolt right in and seal up to the housing nicely. It even comes with a nice new set of gaskets for the back side. We have the same upper radiator hose on it. Our old one is actually why we removed it. It's starting to leak around the top edge here, and that's not really a terrible leak, but we would rather do it now than do it later when the leak becomes more severe and prevents us from driving our vehicle.

We have the same inlet for our thermostat and the same heater core outlet fittings on the end, as well as the three threaded bolt locations for our belt tensioner. If your water pump has failed and is leaking from any of these gasket surfaces, the seal at the bottom, or the hose fittings, this new part from 1A Auto is going to go in direct fit, just like your original equipment, and fix you up right.

Use a clean rag or paper towel, I'm just going to remove all the moisture from the surface that the gasket's going to mount. We're going to spray some brake cleaner with another clean paper towel. Just wipe any dirt and debris and oils that might be on that surface, just to make sure that nothing interferes with us getting a good seal the first time. I've sent all the bolts back through right where they go, and I'm now installing the gaskets onto the bolts just to make 'em a little bit easier to line up. I'll now very carefully set the new water pump into place.

I'm just going to take my 10mm extension and socket off of the ratchet and use those to help line up the bolts. I'm holding it pretty far away right now, and all I'm doing is just sending the bolts through very slowly so we don't knock the gasket out of place. Just going to get all three of 'em started a couple of threads, so we know everything's where we want to go, and then we'll worry about tightening it down. Torque the water pump bolts to 11 foot-pounds. Compress the clamp and reinstall the upper radiator hose.

Reinstall your heater core hoses. Set the clamps back into place. Install your new thermostat and housing assembly, along with the two 10mm bolts. Torque these bolts to 11 ft. lbs.

Reinstall the lower radiator hose, and slide the clamp back into place. Reinstall the serpentine belt tensioner onto the water pump housing cover. Two longer bolts go in the upper holes, and the shortest bolt goes on the bottom. Tighten these bolts with a 15mm socket and ratchet.

Install the belt over the front grooves of the harmonic balancer or crank pulley. Bring the right side over top of the pulley. We'll then go over top of the water pump and loop under the power steering pump. Over the alternator. Under the idler pulley. Now I'll keep this piece in my hand, make sure that everything is seated because this one's kind of tight, you're going to want the room.

Using my 15mm wrench, I'll take the tension off of the tensioner pulley, slide the belt over, double-check that our path is right, all of the belt is properly seated, and then let the tension back on.

Reinstall the radiator fan and clutch assembly onto the threads of the water pump pulley. Again, you should be able to get this pretty much bottomed out by hand. Reinstall your clamp or whatever method you used to keep the water pump pulley from turning. Then tighten it back down with either the right wrench or your adjustable and remove the C-clamp. Lift up on the upper radiator hose, and reinstall the upper fan shroud. There are two little pins, one on each side, that'll help you to align everything, and then we'll reinstall our four plastic clips by popping the basin and then locking the center pin down.

Reinstall the two 10mm screws at the top. Tighten them down with a 10mm socket and ratchet. Reinstall the hoses back into their clips. Reinstall the intake tubing, it's easiest to set it onto the throttle body. Reengage the hoses into their clips. Then get the boot over the air box. Then tighten down both clamps with a flat blade screwdriver.

Be sure that your petcock is closed before refilling the coolant, and that the hose is folded back up into its holder on the side of the radiator.

Refill your coolant. This vehicle uses the orange coolant Dex-Cool. Make sure that it is either pre-diluted or if you buy concentrated full strength that you mix it 50/50 with distilled water. We'll fill it up as much as it'll take, and then back our vehicle outside to finish bleeding the system while it's running. Don't be afraid to overfill it, because once our vehicle runs and gets up to temperature the thermostat will open and that fluid will all go into the engine block.

Set your vehicle with the fan on the lowest speed, set to hot in the vents so you can feel the warm air coming out of the vehicle. This will also open any bypass valves that prevent coolant from entering the heater core when shut off. This is another place that air pockets can build up. Now we'll let our vehicle run up to temp, and keep the coolant topped off in the process.

Now we just had to add just about a gallon of coolant to the vehicle once it got up to temp. Now we'll keep an eye on it, wait for it to finish bubbling, our heat to get hot, and the level to stabilize before we'll finally top off our fluid and take our vehicle for a test drive. Once your fluid is finished bleeding, and it's topped off reinstall your cap and test drive your vehicle.

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