350 Water Pump Woes

[scrap--metal]

Wow! Maybe they use the same crusty back plate after "remanufacturing" the internals.

Assuming it's not ancient, I'd take it back to NAPA. That's not how water pumps typically fail.

 

[racerboy9]

There is a stainless steel back plate for marine version water pump. I may go that route if it pans out. There is one on Ebay: https://www.ebay.com/itm/174555963839

 

[Bextreme04]

Pulled the pump and same back plate problem as my last one. Erosion, corrosion and pinholes. Always had anti-freeze mix. I could just put a new back plate on but given the work involved it seems better to get a new pump with a more heavy duty back plate. Most of the new pumps tout being "high flow" but I don't really need more flow.

How long has that been on there? That's a lot of corrosion and damage for even a rebuilt pump. I would suggest maybe switching the brand of antifreeze as well. Maybe just switch to the standard extended life prestone. I have MANY miles and years of driving with it in all kinds of vehicles with no corrosion issues.

 

[Ricko1966]

Pump cavitation pics

 

[SirRobyn0]

Wow! Maybe they use the same crusty back plate after "remanufacturing" the internals.

Assuming it's not ancient, I'd take it back to NAPA. That's not how water pumps typically fail.

I said that something earlier. Purchase a quality brand new pump, use coolant mixed properly either premixed or distilled water, and why not check the pH with test strips couldn't hurt. Heck there is a lot of coolant still in the block, maybe it's way out of whack. I think the take away from this imo is to be thorough and it should be fine this time.

One final though from me is if some how there is a small amount of exhaust gas getting into the coolant that would make the coolant pretty corrosive,but generally there are other issues going on with the motor in a situation like that.

 

[Turbo4whl]

I believe Rick hit the answer. The pump is cavitating because a lack of flow. So check the lower hose when running to see if it sucks in. That is why there should be a metal coil spring in the lower hose. Or, the radiator cross tubes are clogged and not enough flow.

The cheap metal rear pump plate, recycled metal probably has hard un-melted pieces that pull out first from the cavitation.

 

[racerboy9]

So I bought the stainless steel back plate and have all new hoses and belts on the way. Flushed the block, heater core and radiator. The pump had low miles and seems fine so I am reusing it. I am going back with the old Prestone green coolant and crossing my fingers I have fixed whatever was wrong.

 

[SirRobyn0]

I believe Rick hit the answer. The pump is cavitating because a lack of flow. So check the lower hose when running to see if it sucks in. That is why there should be a metal coil spring in the lower hose. Or, the radiator cross tubes are clogged and not enough flow.

The cheap metal rear pump plate, recycled metal probably has hard un-melted pieces that pull out first from the cavitation.

Ok so I'm going to be "that guy" to carry on the lower hose debate. So we all know it's possible for a lower hose, particularly a high mileage soft hose connected to a not so clean radiator to collapse down. But what about that spring in the lower hose? Years ago you could get a replacement hose with a new spring in it. I can't say when the last time was I saw one, 20 years ago maybe? And it's a pretty rare day that I see an old vehicle that still has it's spring in the lower hose. So what gives? Well I asked gates that a few years ago and basically got back, that yes lower radiator hoses need something to prevent the risk of collapsing down, but most modern manufactures build that reinforcement into the lower hose which eliminates the need for the spring, and the risk of it corroding and ending up in the water pump. I think the take away is if you feel more comfortable with a spring in your hose and the spring is in good shape run it. Otherwise a good quality hose, certain a gates hose no longer requires the use of a spring.

 

[Turbo4whl]

Okay, I could debate. First I did state, "run the engine and see if the the lower hose sucks in." Second, the shape, length and diameter all have a play in whether or not the lower hose needs reinforcement. Remember, I have worked on medium duty trucks longer than most of the peeps on this forum have been alive. Some replacements still come with a spring. Square body trucks had springs in the lower hose from new.

You are probably right about a new quality replacement hose, but how many parts are now made overseas? Going back, the springs were either brass or stainless. Yes, not any more.

 

[racerboy9]

Earl's make the stainless inner support springs.

 

[SirRobyn0]

Okay, I could debate. First I did state, "run the engine and see if the the lower hose sucks in." Second, the shape, length and diameter all have a play in whether or not the lower hose needs reinforcement. Remember, I have worked on medium duty trucks longer than most of the peeps on this forum have been alive. Some replacements still come with a spring. Square body trucks had springs in the lower hose from new.

You are probably right about a new quality replacement hose, but how many parts are now made overseas? Going back, the springs were either brass or stainless. Yes, not any more.

Interesting info. I don't work on medium duty so did not know that, and I'm sure the answer I got from Gates was regarding light duty / cars. And you are certainly right about oversees parts, so many once well known quality parts manufactures have done that and as you know quality seems to go to hell in a hand basket at that point.

 

[rusted nuts]

Check the hardness of your water...lol, just kidding. Napa now sells mostly cheap Chinese junk. I just bought and installed a Tuff Stuff pump. It was so purty and well built I almost just put it on the shelf.

U may of been kidding but people in the know keep a eye on the ph in diesel cooling sys.

 

[Bextreme04]

The answer he

Interesting info. I don't work on medium duty so did not know that, and I'm sure the answer I got from Gates was regarding light duty / cars. And you are certainly right about oversees parts, so many once well known quality parts manufactures have done that and as you know quality seems to go to hell in a hand basket at that point.

re is that the manufacturer knows if the hose is reinforced or not. If not, they come with a spring or state to re-use the one already there. Modern light duty vehicle hoses no longer need one in all but the cheapest hoses. The new ones are SOOOO much stiffer than the old rubber radiator hoses. I have yet to see one collapse without there being a completely clogged radiator or the hose being completely degraded from a blown head gasket or similar issue putting oil into the coolant for an extended period of time.

 

[clegko]

This is probably a bit unrelated, but I used to have this issue constantly on my junk. The last time I was replacing the water pump on my truck, the only coolant I had with me was Zerex's G05. I shrugged, flushed the system, and used it and distilled water and haven't had a single water pump issue with the truck since. The price is close enough to the old green **** that I just buy G05 for everything now and haven't had any issues with any of my stuff, assuming you actually flush the system when switching.

 

[Bextreme04]

This is probably a bit unrelated, but I used to have this issue constantly on my junk. The last time I was replacing the water pump on my truck, the only coolant I had with me was Zerex's G05. I shrugged, flushed the system, and used it and distilled water and haven't had a single water pump issue with the truck since. The price is close enough to the old green **** that I just buy G05 for everything now and haven't had any issues with any of my stuff, assuming you actually flush the system when switching.

The OP stated he is currently using the Zerex GO5