Water pump and thermostat

[L31MaxExpress]

Those are the ONLY way I got to the bypass hose clamps between the T stat housing and the alternator.

I had to remove the fan and alternator bracket.

 

[HotWheelsBurban]

I had to remove the fan and alternator bracket.

The Burb has the 145 amp alternator and it's bigger than the 100/105 amp ones the pickups got. That larger case means less room to work. I was working on the Burb in my cousin's driveway, in a nice suburb of Houston, and I basically had that day, to get it fixed and moved, so he could put his truck and swmbo's Impala back in the driveway for them to go to church in the morning. He saw the difficulty I was having, trying to get to those clamps, and came up with the pliers. Tricky to get the hang of using, but they do the job!
To get access to the pump, I pulled the top half of the fan shroud; once the fan, belt and clutch were off I had plenty of room. But this is a 350.... I'm not anticipating too much difference, when Rawhide gets a new water pump and hoses (hopefully next month when I have some more $$$, got some extra expenses for this month).

 

[fishmagnet]

I installed a Dayco water pump on the '98 Tahoe three years ago and all still good!

 

[Streetfighter]

Hey guys, new guy here,
Water pump went on my 92 Silverado 7.4 this morning on my way to work, looking for tips or tricks anyone has picked up for replacement of pump and thermostat.

Cheers!

J Miller

O’Rileys your best bet.

 

[mbowman]

Ensure you do a thorough flush. The debris inside the coolant passages that likely caused your pump fins to fails is going to attack your next pump. Run the engine without the thermostat w/ water or flush solution so get all the junk dislodged. Then refill w/ coolant and put your new thermostat in.

 

[95Noobie]

Quick followup question. I have a 1995 Chevy 305 with gasket visibly sliding out from behind the water pump and a slow weep. I'm reading about several brands here but can't find online or local parts store. The AC-Delco lists a clockwise (251-725 which does not seem like a true AC-Delco part number) and a counterclockwise direction pump (252-719) which both 'fit' my year/make/model? How can that be and how can I tell? Otherwise Oreilly has a Murray brand that is 'heavy duty' I can't imagine these can be very heavy duty when you can get one for $39 (masterpro house brand) and the heavy duty Murray is about $50? Where can i find the brands listed in earlier posts?

Most of the offerings on the online parts pages all are counterclockwise so perhaps that is going to end up being what I need?

I can get Advanced Auto store brand or AutoZone store brand with 'limited lifetime warranty' but just would rather not have to go through all the work for several years if possible.

This will be my first crack at it so will I need a special tool or will I need to fabricate something to hold the fan to help break it loose? I already have a new thermostat and coolant sensor so hopefully will be able to protect those during the install.

I see for a few dollars more I can get a water pump with fan clutch replacement. Worth the extra few dollars while I'm at it?

Will the bolts reach the water jacket on the 305 and require any special 'sealer' Thanks in advance!

 

[Schurkey]

1995 Chevy 305

AC-Delco lists a clockwise (251-725 which does not seem like a true AC-Delco part number) and a counterclockwise direction pump (252-719) which both 'fit' my year/make/model?

That's a statement, not a question.

Serpentine belt? If the water pump pulley is smooth, you need the counterclockwise rotation. If the pulley has multiple lil' grooves, you need the clockwise rotation.

Will the bolts reach the water jacket on the 305 and require any special 'sealer'

I'd use Loctite/Permatex 592 sealer on the bolts. Clean the male bolt threads, and female block threads.

 

[95Noobie]

mbowman suggest I take my thermostat out, close the housing back up, run the engine to dislodge all the junk. I assume I'm doing this while having a drain open somewhere and adding fluid at the same time? It would seem to make more sense to do that with the current 'old' water pump in place yet so maybe take off the bottom hose and add water somewhere higher up in the system (top hose or radiator cap?) I probably don't want junk going through the new water pump if I can help it.

The truck came to me with a new radiator so hopefully at some point the system was emptied and flushed before refill but this is a good time to do it again.

 

[95Noobie]

Returning to report success with the water pump install and thank you for your help. I did require the CCW rotation pump. Thanks to some youtube advice I was ready for the challenging parts. Getting the factor bung out of the top hole proved very difficulty. Since this is a temporary plug I have no idea why the factory torqued it to 2,300,500 foot pounds. I could see at some point that the hose going to the firewall had lost its factory connector and that my setup now included a thread in nipple with barb style fitting for a hose to clamp over. Fortunately it was fairly easy to back that one out (I loosened it while it was still installed on the truck) Was a bit worried about loosening the fan stud nuts and getting those studs backed out and transferred over to the new pump but that part proved quite possible with tips mentioned above. Thanks for advise on the thread sealer on the block bolts and I used some permatex water pump gasket sealer on the gaskets and mating surfaces. I was surprised how easy it was to get the 4 mounting bolts loose, they felt like they were about 20 ft/lbs which I guess the service manual calls for around 30 so were torqued correctly.

Before the old one was off I flushed the system with hot water till it ran clean. I didn't give it a full 24 hours for all the gasket maker/thread sealer to set up, I gave it about 8 hours. Then refilled, did my best to burp the lines. Took forever to get bubbles out under idle, then finally thermostat opened, levels dropped in radiator. Refilled, burped again and watched it till didn't see any more bubbles. Added a little in the reserve tank. Took for test drive. So far no leaks and good heat coming in the cab. Wonderful!

The other good thing that happened while putting fan shroud back on I noticed an odd bend in the vacuum line that heads over behind the alternator and to the cannister behind the drivers headlight area. I saw an odd bend in it and some black duct tape that I hadn't noticed before. Clearly the line was broken and very poorly patched. I removed tape and repaired with tight fitting section of rubber hose. Assuming that is/was a vacuum leak that no longer is leaking then hopefully the rest of the vacuum system will be happier in the future.

Thanks!