Waterpump replacement for '96-'99 Vortec motors.

[CKTA]

1. Drain the coolant.

2. take the 7 bolts out that hold the top piece of the shroud.

3. Use a wrench, Channel locks or big cressent wrench on the "nut" of the fan. And easy way to get it of is to have the serp. belt stll on and w/ a 10mm open end wrench put the round (12pt end) on one of the 4 bolts on the waterpump pulley. When you rotate the pump around the 10mm wrench will "catch' on the crank pulley and give you a solid base to loosen/tighten the big nut.

4. take the 4 pulley bolts off. (w/ the serp belt still on)

5. Take off the serp. belt.

6. Take off the idler pulley. (easier to get to the rubber hoses on top)

7. take off the lower rad hose and 2 upper rubber hoses.

8. Take out the 4 main waterpump bolts and pry unit off the block.

9. Scrape/clean the block mounting surfaces.

10. Assemble in reverse order torqing the bolts to 30 ft pds. (put thread sealant on all 4) Don't forget to use the 10mm wrench trick to tighten the big nut.

[Joe]

Should be titled '...for '55-2003'

[CKTA]

Originally posted by gmcjoe
Should be titled '...for '55-2003'

Correction, on different models you may or maynot have to remove #6. and you may have to remove different things depending on year/make/model of differnt trucks. This is exactly what you have to do for the '96-'99 Votec's!

Thanks for your once again useless info!

[Joe]

Originally posted by CKTA


Thanks for your once again useless info!

My pleasure

[hccp]

I happen to have done this on my 97 tahoe not to long ago and I found it difficult to remove the large nut without sh^t turning so I ordered a fan clutch holding tool from the tool truck. Works sweet! If need I can send you a template to make your own out of flat bar. Good tips though. Later

Made the job on my 88 and 89 seem like a 10min oil change with the heater bypass hoses and their location/clamps.

[geno96Z71]

Guys,
I've got a mysterious coolant leak coming from the underside of my water pump (but not from the weep hole). Of course I discovered this after replacing that POS heater hose fitting on the lower intake- anyways, I think I'm SOL here and I need to install a new water pump. The dealer wants $191 for a new one- talk about a hose job! Any recommendations for a reasonable aftermarket or parts store substitute?

Geno

[PerfectSleeper]

I just replaced my water pump today. I got it at autozone for $30 bucks with a lifetime warranty. You can also get them at Kragen or Napa for about $35. Took me only about 2 1/2 hours. Good Luck

[2doortahoe95]

Just did my water pump on my 95 tahoe, yesterday. In reply to geno96z71, I was having leak probs too. I thought it was the lower hose but found it to be the quick disconnect fitting on the hose that screws into the top of the waterpump. Everytime I would shake the hose it would spurt out.

Might want to remind people, everytime you change the water pump to replace this fitting otherwise you might have leaks. I also found those hose clips to be a bizatch to clamp without big pliers or the specific hose clamp tool. Ended up using a grip clamp/c-clamp to open the clip.

[geno96Z71]

2door,
I ended up having to replace my water pump, along with a new set of intake gaskets. Picked up a new replacement (Bosch, $60) at Pep Boys.

Geno

[2doortahoe95]

Yeah it's hard as hell to keep the gaskets on the pump when your reinstalling it onto the block. Even with RTV sealant on I kept dropping them, luckily underneath.

[Fast4drss]

Any recommendations to tighten the large fan nut back on.
Is there a torque rating? Just tighten and a little extra to make sure? Is serviceable locktight required?

Thanks,
Brian
96 GMC 4.3L

[hotroddually]

It doesn't take all that much because as soon as you crank the engine the direction that the pulley turns will tighten it.

[Regal1]

I learned a cool trick from a buddy who works at a dealership. If you have an air hammer, you can use it to catch the edge of the large nut and loosen it. I used a broad chisel bit and it chewed up the edge of the nut a little, but not enough to hurt anything. You can use it to tighten also, just BE CAREFUL, it doesn't take much torque at all.

[CKTA]

Originally posted by Regal1
I learned a cool trick from a buddy who works at a dealership. If you have an air hammer, you can use it to catch the edge of the large nut and loosen it. I used a broad chisel bit and it chewed up the edge of the nut a little, but not enough to hurt anything. You can use it to tighten also, just BE CAREFUL, it doesn't take much torque at all.

Be very carefull, the impacts could damage the bearings in the pump very easy.

[hotroddually]

Ok, I always forget, is the big nut reverse threaded or is it normal?

[CKTA]

Normal.

[BigSwede]

I tried CKTA's method for loosening the "big nut" to get the fan off, but just effectively tightened the snot out of the 10mm bolts on the water pump pulley. Fearing that I might snap one of those bolts off, I went to NAPA and bought a "Universal Pulley Holder/Fan Clutch Tool" for $28. It worked well, and hopefully will be of use in the future, as it is "universal".

Cheaper alternatives might be available from Northern Tool or Harbor Freight or the like, I don't know, but I needed the tool right then.

[cl1986]

Well here goes,

Followed instructions. Went really good. Easy level of 1

Make sure you have plenty of light, a 4ft shop light works great, just dont keep hitting your head on the clamps.

To get the big fan nut off DONT use the 10mm wrench on one of the 4 pully bolts, lickely to twist them off. I used a big cresent wrech and keep hitting it with a hammer and eventually it will break loose. It took about 50 hits, dont smack it real hard, u just need light taps to jar the rust loose. Dont waste $28 on a tool u wont ever use agian.

Remove the lower shroud to acces your stupid placed drain plug and let the water run all over the place, why cant the just put a 6" hose on that and run it right into a bucket??

The pump removal was a piece of cake, by the way u will still have water in the lowe radiator hose that will go all over causing a big mess.

To put the new pump on, read instructions that came with pump and use some tacky sealer to hold the gaskets on and some thread lock on the 4 bolts and torque them to 30 ft lbs.

When removing your dumb hose clamps, make sure you have a proper tool like a big plier to squeeze the clamp, my little plier slipped off and rammed into the radiator, hope that doesnt leak..

Over all this is super easy, hardest thing was big nut, just tap on it till it breaks loose, my truck has 113,000 miles on it and is a 98,

Good luck

[75gmck25]

I'm trying to use the complete serpentine belt system from a '99 350 engine on my '75 vintage 350 engine. I am using an Edelbrock Performer manifold and carburetor, and I have standard (not Vortec) heads on my 350. I have everything figured out except the two small hoses on the '99 water pump.

My '75 has one heater hose connected to the intake manifold and the other connected to a small hose connector on the radiator. There are no small hoses connected to the water pump.

The '99 water pump has two small hose fittings on top. It looks like one was connected to the intake manifold with a short hose, and the the other has a connecting hose (metal/rubber combination) that heads in the direction of the heater hose. I also have a section of heater hose that has a vacuum-controlled valve in it.

If I want the bypass system to work properly when the thermostat is closed/open, where do I connect the small hoses on the water pump? My first guess is the one on the passenger side goes to the intake manifold and the other one goes to the heater hose. However, I don't have a '96-99 to take a look at and verify the connections.

Thanks,

Bruce

[CKTA]

Originally Posted by 75gmck25

I'm trying to use the complete serpentine belt system from a '99 350 engine on my '75 vintage 350 engine. I am using an Edelbrock Performer manifold and carburetor, and I have standard (not Vortec) heads on my 350. I have everything figured out except the two small hoses on the '99 water pump.

My '75 has one heater hose connected to the intake manifold and the other connected to a small hose connector on the radiator. There are no small hoses connected to the water pump.

The '99 water pump has two small hose fittings on top. It looks like one was connected to the intake manifold with a short hose, and the the other has a connecting hose (metal/rubber combination) that heads in the direction of the heater hose. I also have a section of heater hose that has a vacuum-controlled valve in it.

If I want the bypass system to work properly when the thermostat is closed/open, where do I connect the small hoses on the water pump? My first guess is the one on the passenger side goes to the intake manifold and the other one goes to the heater hose. However, I don't have a '96-99 to take a look at and verify the connections.

Thanks,

Bruce

Good question, but I'm not 100% sure. You may be better off making a new thread in the forums to get more views and hopefully an answer. BTW, welcome to the site.