How do you replace the water pump on a 1999 Chevy Tahoe?

Answer 1

Response to below:As stated in my below (referencing the 1996 Tahoe) I used a very large adjustable wrench (I think it is a 14in), I believe I also had to use something to hold the fan from moving while I did this.

- I don't recall if the threads are normal or backwards (sorry)

- The tool AutoZone had to rent was for FORDs and did not work when I tried to use it.

not been able to remove fan from water pump. dont know if it takes special tool to do this or what?

Some parts stores have a tool you can rent or borrow. It is not a special tool it is just a really long angled wrench that lets you get to what you need. It will actually be a set of two wrenches. Autozone had them when I changed mine a few years ago.

-This is from a 1996, so some things may be slightly different

It has been a couple years since I did it, but as I recall... I removed the fan cowl for working room-while waiting on remaining antifreeze to drain then got a big a** adjustable wrench (I had to buy one because it was the only thing I could find that would work) and removed the fan from the pulley I think I had to put something though the hole in the pulley to keep it from moving. Remove belt ( I assume you know how to do this) locate bolts at each end of the water pump, remove, and scrape off old seal. I believe I had to use some RTV to create new seal, then bolt back together, and check directions on RTV for drying time before refilling with antifreeze/water. You may also want to remove the pulley from the old pump before removing it from the block as you will need it with the new one as well. and I found it easier to do this way.

ANSWER:

I replaced the water pump on my 1999 Tahoe when I replaced the timing chain & gears. Remove the upper fan shroud to get good access to the fan mounting nuts. I would recommend using a chain wrench to get enough torque on the pulley to remove the nuts that hold the fan on. Be sure to put a rag over the pulley to keep from galling the pulley surface (or just buy a new pulley). This will prevent any galling of the pulley surface from damaging the serpentine belt after putting back together. The pump I bought just had the mounts on it for the pulley (didn't come with new pulley) & I was able to reuse mine, since I did not damage it with the chain wrench (used a couple of rags to protect the pulley as mentioned before). You can easily drain the coolant from the block by removing the knock sensor on the side of the block next to the oil pan. This makes it easier to get the coolant out so you don't make a mess when you take the pump off. If you use a clean enough garage and bucket, you could even strain filer and reuse the coolant. The stuff is around $10 a gallon!

I am not a big fan of RTV sealer, but it is an option (small beads of dried sealer can break off and clog coolant channels in etc. Especially small coolant channels in the head, block and transmission cooler lines. Had a buddy have an oil pump go out and blow an engine thanks to RTV sealers. I also have heard transmission guys talk of all sorts of Horror stories of transmissions going out for the same reason.... RTV sealer). That's why they make gaskets.

If you want to have the gasket to adhere to the parts for easier installation, you could use high tack adhesive or grease. I would recommend a food grade equipment grease for an antifreeze coolant system to prevent petroleum based molecules causing cavitation on your water pump. Plus, if you don't use these sealers you don't have to wait a day for the sealer to cure to drive your car. If you work on your car in colder temperatures, you would have to keep the sealer warm enough to cure properly, which is hard in the winter months (could use a halogen light or a heat gun for a couple hours I suppose). Unfortunately, GM has gotten cheap and gone away from gaskets and likes to use RTV sealers in some applications (for example Saturns use RTV sealers for the timing chain and oil pan gaskets. might be why Saturn use so much oil!!!!!). Fortunately, you can still buy the water pump gaskets for the 1999 Tahoe!!!!

If you do go with the sealer, Just make sure that you get the proper sealer to use on water pumps and that the surfaces are really clean before applying. The chemicals in the anti freeze can cause some sealers to not seal properly. Brake cleaner is usually the best surface cleaner since it doesn't leave a residue like degreasers. Apply the sealer SPARINGLY!, since you don't want it to overlap past the gasket and break off into your coolant system when the gasket is pressed together (I already mentioned what can happen when a chunk of sealer breaks off into you system). Plus, be sure to read the curing temperature and time if you go with an RTV sealer.