Replace gasket only on water pump?

[The motor guy]

Can't you just throw a new gasket or even coat it with rtv and throw the pump back on? The mechanic told me the bearing gets water in it when the seal leaks. This been sitting on my shelf for like 5 years and I expected to not be able to even turn the pulley, but it seems fine. Unless it's supposed to easily turn a couple times with my hand. This is the one off my cummins. It runs off the belt on a separate area of the engine and isn't behind the fan like most are and only takes 10 minutes to change

 

[Dave9]

I'm not following what you're stating. This is a used pump or new?

Typically the seal on the pump shaft starts to leak from wear, and there's a weep hole around the gasket, that lets that escaped coolant drain out to warn you of its pending demise. It's not the gasket itself that usually leaks unless it was installed poorly, something warped or mating surfaces not cleaned off well, or if sealant was needed, not put on well.

IDK that being able to turn it means much. It could turn fine with the seal shot, and I've even installed a water pump that seemed to turn fine by hand but bogged the engine down when giving it throttle so returned it for another which worked fine, proving the pump that seemed good, wasn't.

If you think the pump is good still, sure, put a new gasket on and/or use some RTV, but I wouldn't trust it till I saw whether it leaked again. I could be completely misunderstanding your post!??

 

[The motor guy]

It's an old pump I took off. I bought a new $300 pump to replace the old one. So you're saying the bearing has nothing to do with it? I disagree. I think after a while the gasket hardens and no longer seals. This pump pictured, tge gasket is basically flush and flattened out. It was my understanding it kept the coolant and the bearing separate also. Maybe it just keeps it from leaking out

 

[vavavroom]

It's an old pump I took off. I bought a new $300 pump to replace the old one. So you're saying the bearing has nothing to do with it? I disagree. I think after a while the gasket hardens and no longer seals. This pump pictured, tge gasket is basically flush and flattened out. It was my understanding it kept the coolant and the bearing separate also. Maybe it just keeps it from leaking out

The water pump gasket seals the water pump against its mounting flange. This seal keeps coolant from leaking out.

The water pump contains an impeller that's pressed onto a shaft which has a sealed bearing. When the seal on the bearing fails due to wear and heat cycling, water will get into the bearing which will cause eventual but catastrophic coolant pump failure when the bearing either seizes or disintegrates. When there is water ingress into the bearing, coolant will drip from a weep hole to indicate impending

How much resistance this pump normally puts up when in working order with a good bearing I do not know. The only part that doesn't appear to have surface corrosion is the impeller. Is that metal or plastic?

 

[The motor guy]

The water pump gasket seals the water pump against its mounting flange. This seal keeps coolant from leaking out.

The water pump contains an impeller that's pressed onto a shaft which has a sealed bearing. When the seal on the bearing fails due to wear and heat cycling, water will get into the bearing which will cause eventual but catastrophic coolant pump failure when the bearing either seizes or disintegrates. When there is water ingress into the bearing, coolant will drip from a weep hole to indicate impending

How much resistance this pump normally puts up when in working order with a good bearing I do not know. The only part that doesn't appear to have surface corrosion is the impeller. Is that metal or plastic?

I think it's aluminum. Hard to tell. Sounds metallic when I flick it with my finger.

 

[D60]

Sure, the rubber gaskets flatten and harden. They can leak.

 

[vavavroom]

If you can't get a new gasket you can make one.

 

[The motor guy]

So is my mechanic right that the bearing gets contaminated with coolant?

 

[Jetronic]

So is my mechanic right that the bearing gets contaminated with coolant?

He's not talking about THAT seal, there's another behind the impeller

 

[NibbanaBanana]

The pump housing has to be sealed with the round rubber gasket that's in the grove, and the impeller shaft has to be sealed. The bearing is on the outside of the seal. If the impeller seal is leaking a little and the motor gets regular use, it could go a while. If it sits it will corrode and seize up. Either way, it's not reliable. You can probably disassemble and replace both seals.

How many miles on the old pump?

 

[TomYoung]

Throw the old pump away.

 

[The motor guy]

The pump housing has to be sealed with the round rubber gasket that's in the grove, and the impeller shaft has to be sealed. The bearing is on the outside of the seal. If the impeller seal is leaking a little and the motor gets regular use, it could go a while. If it sits it will corrode and seize up. Either way, it's not reliable. You can probably disassemble and replace both seals.

How many miles on the old pump?

Like 190k probably. I don't quite remember when it was replaced.

 

[ecotourist]

There are 2 "seals". There is the gasket that seals the pump against the block, and the seal that prevents coolant from getting into the bearing (and coming out through the weep hole).

You can easily replace the gasket but that's not (usually) the problem. The seal on the bearing is what has usually failed and it's not easily replaced.

So most likely you're just wasting time putting on an old water pump with a new gasket.

 

[The motor guy]

There are 2 "seals". There is the gasket that seals the pump against the block, and the seal that prevents coolant from getting into the bearing (and coming out through the weep hole).

You can easily replace the gasket but that's not (usually) the problem. The seal on the bearing is what has usually failed and it's not easily replaced.

So most likely you're just wasting time putting on an old water pump with a new gasket.

Oh, so if it's coming out the weep hole, then it went through the bearing? Got it. If it was just a outer gasket leak, then you would see antifreeze around the whole pump I assume

 

[paulo57509]

Can't you just throw a new gasket or even coat it with rtv and throw the pump back on? The mechanic told me the bearing gets water in it when the seal leaks. This been sitting on my shelf for like 5 years and I expected to not be able to even turn the pulley, but it seems fine. Unless it's supposed to easily turn a couple times with my hand. This is the one off my cummins. It runs off the belt on a separate area of the engine and isn't behind the fan like most are and only takes 10 minutes to change

The shaft seal should be fine. Provided the "new" pump was stored indoors out of the elements. In-servce is a lot harsher than storage.

You'll see coolant out of the weep hole before water will get to the bearings. Typical WP construction:

 

[Dave9]

Like 190k probably. I don't quite remember when it was replaced.

You want to reuse a 190K pump?

I don't think this is worth the bother.

 

[The motor guy]

You want to reuse a 190K pump?

I don't think this is worth the bother.

No, but with how hard it is to get parts quickly these days, I don't see the harm in replacing the gasket and keeping it on the shelf in a pinch. Say use it for a week or two while you wait for the new one to come in.

 

[Hootbro]

No, but with how hard it is to get parts quickly these days, I don't see the harm in replacing the gasket and keeping it on the shelf in a pinch. Say use it for a week or two while you wait for the new one to come in.

Part of me says you are being cheap for cheap sake, but I can see the allure since it is a $2 gasket.

 

[The motor guy]

Part of me says you are being cheap for cheap sake, but I can see the allure since it is a $2 gasket.

Most water pumps are also a pain to get to. Thus one is two 10mm bolts and she's off

 

[The motor guy]

Most water pumps are also a pain to get to. Thus one is two 10mm bolts and she's off

But I did forget the part where the other poster said if it's coming out of the weep hole, the inner bearing is contaminated