Water pump replacement in a GM V8

[NMBurb02]

My mechanic pointed out a few months back that the water pump on the Burb was weeping and would need to be replaced sometime soon. I could see the signs of slight wetness on the front of the engine below the water pump, but the coolant level remained steady and it never actually dripped...until today. So, should I have my shop take care of it for me (I haven't gotten a quote yet, but am guessing something around $450-500?) or is this something a DIY mechanic with "advanced beginner" mechanical aptitude could handle on his own? The service instructions in my Haynes manual seem pretty straightforward, but are there certain things I should look out for?

If I do it myself, I then have to choose between multiple pump brand offerings. The RockAuto offerings include Cardone, Gates, Airtex, Bosch, Pronto, ACDelco, and Beck/Arnley, in order of least ($50) to most ($148) expensive. The Cardone and Gates are marked with the little hearts that indicate they are favorite parts, but they are the two cheapest, so it may speak more to price than the price/quality value balance I look for. Any advice?

 

[artificialist]

Changing the water pump on such an engine is not too hard. You might have to borrow a fan clutch wrench to disconnect the fan clutch and fan from the accessory drive belt. Also, know exactly what you need to take the drive belt off. Get a new belt, coolant quaickly destroys belts. Check all accessory drive pulleys with the belt off to prevent having to do the whole job again in the future.

As for the water pump, I do not like Cardone pumps. I'd rather use a Bosch or Beck/Arnley pump if I have to take one from that list. If the ACDelco pump is the exact OEM pump I would use that. Sometimes ACDelco is written on an Affina parts group product, and could be high or low quality. A local part store may have a GMB pump which is a good choice, and the nice thing about having a Chevy 350 is that you can get pumps from speed shops which might also save a few dollars.

 

[yonyon]

If you have ready access to a suitable tool for the fan it should be pretty straightforward, otherwise you'll need to decide how you're going to deal with the fan.

Don't forget to order a thermostat.

 

[Chris142]

That pump is a 20 minute job. Pull the top of the fan shroud then the fan.remove the belt,lower hose and 2 heater hoses. Remove 6 bolts with a 10 mm socket and the pump will pull off. Will have to swap the belt tensioner and thermostat over onto the new pump but its that easy.

 

[Merkava_4]

That's how I started out: I was totally scared of cars until a friend of mine let me watch him change a water pump on his 1970 Mercury Cougar. It just so happened that we both had 1970 Cougars back then. I watched him do his, and then I did mine. Thanks to my good friend, I'm not afraid to do anything to a car now.

 

[bama7x57]

You can get it for about $75 at AAP after discount. It will have a lifetime warranty.
It's an easy job. The most challenging part is removing the fan. I use a large (24") crescent wrench. I leave the belt attached and hit the wrench with a hammer in a counterclockwise direction.
here's a good video

http://www.youtube.com/watch?v=fY8uJeM3ArU

 

[caravanmike]

i just did one (september) on my 5.3L sierra

-i used the bosch pump from pep boys (holding up so far)
-i used an air chisel for the fan clutch bolt (worked great)
-my pump was still good only the gaskets failed, but i replaced the pump while i had it apart.
- staight forward job
- u can use a flat blade screw driver for the push pins on the shroud.
-took me 2.5 hours

 

[dailydriver]

I put a lifetime warranty GMB pump on my Z28 all by my lonesome, and it is A LOT harder, and in a MUCH tighter space than your truck's LS engine.

I will have my old Evans high performance pump rebuilt with new seals/bearings, and then install it in the future when the Sino built GMB is on it's way out.

 

[Rhymingmechanic]

It's pretty easy except for removing the fan, as others have said. I know there must be a tool for it, but I've never found a parts store that has it for loan. What I ended up doing was putting small bolts through the pulley so it could be held still with some rigged-up puller contraption I borrowed from NAPA. I then used a big Crescent wrench on the nut.

I got the AC Delco and Fel-Pro gaskets from Rockauto. It didn't impress me as being built as well as the original, but it's OK so far. It looked like my problem was actually the gaskets, not the pump. Research I did suggested those gaskets were a common failure point, and that Fel-Pro gaskets are improved.

 

[gfh77665]

The pump on my daughters Chevy Caprice went out this week. For just $320, I got a new pump, thermostat, and coolant installed.

Total time was 10 minuets dealing with this. 5 to drop off, 5 to pick up.

 

[NMBurb02]

Originally Posted By: bama7x57
You can get it for about $75 at AAP after discount. It will have a lifetime warranty.
It's an easy job. The most challenging part is removing the fan. I use a large (24") crescent wrench. I leave the belt attached and hit the wrench with a hammer in a counterclockwise direction.
here's a good video

http://www.youtube.com/watch?v=fY8uJeM3ArU

That video is really helpful and after watching it I am confident it is something I can tackle.

AZ recommends replacing the fan clutch at the same time as the water pump. Is that really necessary? There are no issues with the fan clutch, as far as I know, and I would rather not spend the additional $60 if I do not really need to.

Also, is there anything else I should tackle during the pump replacement? I will check out the belts, but I believe both are fairly new and know that at least one is only 1 1/2 years old, and will go ahead and replace the T-stat as it is probably the original at 140k+ miles. Do I need to flush the coolant system or just refill after replacing the pump?

 

[The_Eric]

Check the condition of the tensioners/idlers and the bearings. I don't think you need to flush the system unless you see deposits, or the coolant is scurvy. Use an OEM t-stat.

 

[NMBurb02]

I went ahead and replaced the pump and t-stat today. Ended up going with a Bosch pump and Stant t-stat and housing from Pep Boys. Those, two gallons of Prestone DexCool, a small tube of water pump and t-stat RTV, a radiator funnel, and two cans of brake cleaner (I was out and it was on special for two for $7) ran me about $190 after a 21% off online coupon code for the parts.

The process was pretty easy. I used a crescent wrench on the fan clutch bolt, which worked well. Overall, it took me about 8 hours, which included 15 minutes to remove the under engine sight shield and check out the weep hole to see if I was dealing with a bad pump or gasket, about 1 1/2 hours to run to Pep Boys and Napa, cleaning up gunk on the front of the block, coolant refill and burping, oil change, cleanup (which was complicated due to me following the coolant passage blow out step the guy in the linked video above used...not a great idea), finding a lost tool (post to come), and test drive. My wise wife planned on me taking all day to work on the car, which is my MO, even for what should be easy and relatively quick jobs.

 

[Jimmy9190]

Well done..you saved money and did it yourself so you know it was done correctly. It always takes me longer than I expected when I have a project to do, whether it is a truck repair or something for my house. It took me 3 days when I replaced the water pump on my Dakota but that was because the first water pump I bought was defective and also because I cracked my plastic coolant overflow tank when removing it the upper half of my fan shroud. I would always rather take too long on a project than to rush through and have to do it all over again later.

 

[Rhymingmechanic]

Glad to hear you got it changed. My projects usually take awhile, too, especially when I have to chase parts or tools all over town.

I have a couple questions--First, how did you hold the pulley when you loosened/tightened the fan clutch? And was it the pump or gaskets?

 

[NMBurb02]

Originally Posted By: Rhymingmechanic
Glad to hear you got it changed. My projects usually take awhile, too, especially when I have to chase parts or tools all over town.

I have a couple questions--First, how did you hold the pulley when you loosened/tightened the fan clutch? And was it the pump or gaskets?

Actually, I did not do anything special to hold the pulley when loosening or tightening the fan clutch. I left the drive belt on and and just tapped the crescent wrench with a hammer, which worked well enough for loosening. I think the key is multiple light taps in order to not overcome the friction bond between the pulley and belt. Putting it back on, I did not worry too much about holding the pulley in place as the torque spec for the fan clutch bolt on my Burb is only 44 ft/lbs. After the drive belt was on and was nice and snug, I tightened it by hand and then did a few taps with the crescent wrench again.

It definitely was the pump. When I first took a look, I could see some deposits below the weep hole. When I removed the pump and tilted it forward a bit, some coolant spilled out of the weep hole. The gaskets were in pretty good shape when I got them off.