Interesting finds during water pump replacement

Bigmac · May 13, 2023

So while overhauling the cooling system I've made a couple of interesting finds.

First, my mopar water pump, presumably the factory pump with 140k shows some odd build-up or corrosion, almost a degradation of the housing behind the turbine. I don't think it was hurting anything but I thought ghe degradation was interesting and curious of the cause.

The second Item ( hidden in piles of built up crud) was a bolt in a crevice behind the crank balancer. Turns out it was from the timing chain cover. Upon further inspection there is another that is rather loose, and turns with fingers.

Unsue at this point but i think all the dirty gunk on the front of the engine is from coolant from the waterpump vice timing chain cover (which afaik doesn't retain any oil behind it but I cant remember exactly).

TheBoogieman · May 13, 2023

Bigmac said:
So while overhauling the cooling system I've made a couple of interesting finds.

First, my mopar water pump, presumably the factory pump with 140k shows some odd build-up or corrosion, almost a degradation of the housing behind the turbine. I don't think it was hurting anything but I thought ghe degradation was interesting and curious of the cause.

The second Item ( hidden in piles of built up crud) was a bolt in a crevice behind the crank balancer. Turns out it was from the timing chain cover. Upon further inspection there is another that is rather loose, and turns with fingers.

Unsue at this point but i think all the dirty gunk on the front of the engine is from coolant from the waterpump vice timing chain cover (which afaik doesn't retain any oil behind it but I cant remember exactly).

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RTV?

Link · May 13, 2023

When I replaced my water pump the same bolt was missing from the timing cover and one was loose. I installed a new bolt and added locktite to the new bolt and the loose one. No leaks from the timing cover though.

kincaid.0678 · May 14, 2023

Bigmac said:
So while overhauling the cooling system I've made a couple of interesting finds.

First, my mopar water pump, presumably the factory pump with 140k shows some odd build-up or corrosion, almost a degradation of the housing behind the turbine. I don't think it was hurting anything but I thought ghe degradation was interesting and curious of the cause.

The second Item ( hidden in piles of built up crud) was a bolt in a crevice behind the crank balancer. Turns out it was from the timing chain cover. Upon further inspection there is another that is rather loose, and turns with fingers.

Unsue at this point but i think all the dirty gunk on the front of the engine is from coolant from the waterpump vice timing chain cover (which afaik doesn't retain any oil behind it but I cant remember exactly).

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There is an oil seal on the outside of the timing cover and an oil slinger on the end of the crank behind the cover as well so some oil is normal. When you pull the timing cover off you can see the oil pan sticks out past the timing cover to drain back whatever is behind the timing cover

Bigmac · May 14, 2023

kincaid.0678 said:
There is an oil seal on the outside of the timing cover and an oil slinger on the end of the crank behind the cover as well so some oil is normal. When you pull the timing cover off you can see the oil pan sticks out past the timing cover to drain back whatever is behind the timing cover

Yeah Idk gow I forgot about the oil getting slung. anything that moves has to be lubricated...

I'm an alternator and balancer away from pulling the timing chain cover... but another 100$ in parts. As you saw in another thread I have some engine noise. I have to ask if it's worth opening up to replace seals, chain, sprockets, balancer etc, or if I should just put the bolt back in with some lock tight and snug it all back up.

I know I should just do it now...

mrblaine · May 14, 2023

Bigmac said:
So while overhauling the cooling system I've made a couple of interesting finds.

First, my mopar water pump, presumably the factory pump with 140k shows some odd build-up or corrosion, almost a degradation of the housing behind the turbine. I don't think it was hurting anything but I thought ghe degradation was interesting and curious of the cause.

The second Item ( hidden in piles of built up crud) was a bolt in a crevice behind the crank balancer. Turns out it was from the timing chain cover. Upon further inspection there is another that is rather loose, and turns with fingers.

Unsue at this point but i think all the dirty gunk on the front of the engine is from coolant from the waterpump vice timing chain cover (which afaik doesn't retain any oil behind it but I cant remember exactly).

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kincaid.0678 · May 14, 2023

Bigmac said:
Yeah Idk gow I forgot about the oil getting slung. anything that moves has to be lubricated...

I'm an alternator and balancer away from pulling the timing chain cover... but another 100$ in parts. As you saw in another thread I have some engine noise. I have to ask if it's worth opening up to replace seals, chain, sprockets, balancer etc, or if I should just put the bolt back in with some lock tight and snug it all back up.

I know I should just do it now...

I just pulled mine to check my timing marks on my new rebuild a couple days back. Took about an hour.

freedom_in_4low · May 14, 2023

mrblaine said:
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I had the same thought. I don't know how much safety margin is built in to a properly running cooling system, but anything that brings the coolant closer to being able to boil (elevated temp, unpressurized due to leaky cap, or insufficient antifreeze percentage) could contribute.

mrblaine · May 14, 2023

freedom_in_4low said:
I don't know how much safety margin is built in to a properly running cooling system,

Don't you have a gauge for that you can read?

freedom_in_4low · May 14, 2023

mrblaine said:
Don't you have a gauge for that you can read?

I only have gauges for what the PCM has a sensor or a calculation for, so no.

RE: the thread your sarcasm references, I asked a genuine question about what point in the cluster ECT gauge you find concerning since having the exact number isn't important, and never got an answer.

mrblaine · May 14, 2023

freedom_in_4low said:
I only have gauges for what the PCM has a sensor or a calculation for, so no.

RE: the thread your sarcasm references, I asked a genuine question about what point in the cluster ECT gauge you find concerning since having the exact number isn't important, and never got an answer.

What number do you find concerning enough to change what you're doing?

freedom_in_4low · May 14, 2023

mrblaine said:
What number do you find concerning enough to change what you're doing?

I replaced a fan clutch last year and am going to be replacing a water pump and radiator this week because I was seeing 230 last summer when cruising over 70mph with the AC on in 100F temperatures, and also extended idling in the same conditions. I'm also replacing the thermostat (a superstat I installed in 2021) because out of nowhere it stopped reaching the 2 in 210 during low speed cruising and extended engine braking out of the mountains...scanner told me it was about 180 which tells me the stat is opening when it shouldn't be.

The radiator is starting to seep at the upper tank seal now so I need it anyway, and afaik water pump is original so it's not gonna hurt anything to change it, but if I do all that and it's still seeing 230 on the scanner it's good to know I don't need to keep chasing it.

Now back to this possibly cavitated water pump...is this something you see often? Unpressurized 50/50 boils in the low 230s IIRC, so a leaky cap combined with a couple needle widths past 210 could definitely allow for bubbles to form in the water pump inlet.

JKP · May 14, 2023

The cavitation was probably caused by a weak cap and/or weak antifreeze. My buddy bought a 97 TJ brand new, never changed the coolant. It had a metal impeller on the pump. When it overheated, he pulled the pump, only thing left of the impeller was the flat disc, no vanes.

Bigmac · May 14, 2023

JKP said:
The cavitation was probably caused by a weak cap and/or weak antifreeze. My buddy bought a 97 TJ brand new, never changed the coolant. It had a metal impeller on the pump. When it overheated, he pulled the pump, only thing left of the impeller was the flat disc, no vanes.

Interesting. Could have been neglect by a previous owner. When I got it, it had a Griffin aluminum radiator. part of the build was replacing with a mopar and a full coolant flush and refill, water pump was not replaced though.

mrblaine · May 14, 2023

freedom_in_4low said:
Now back to this possibly cavitated water pump...is this something you see often? Unpressurized 50/50 boils in the low 230s IIRC, so a leaky cap combined with a couple needle widths past 210 could definitely allow for bubbles to form in the water pump inlet.

I'm not sure we are using cavitation in the same manner.

freedom_in_4low · May 14, 2023

mrblaine said:
I'm not sure we are using cavitation in the same manner.

Ah. Yeah I'm thinking of it as when the points in the pump with the lowest pressure actually get low enough for the fluid experience to spontaneous and localized boiling, but the damage can be similar from just having entrained air...either way parts are being struck by a liquid-gas mixture and it's not good.

freedom_in_4low · May 14, 2023

mrblaine said:
I'm not sure we are using cavitation in the same manner.

This link has some good descriptions.

https://www.globalpumps.com.au/blog/what-is-pump-cavitation-and-how-to-prevent-it

Referencing the quote below, I'm talking about #1, I'm guessing you are talking about #5 (I cut out some that occur outside of the pump to shorten the quote) and then there's #4 which I hadn't previously considered but might occur with a collapsed lower radiator hose or where someone has capped the heater hoses to stop a heater core leak instead of installing a bypass.

Cavitation Defined: Cavitation is the formation and accumulation of bubbles around a pump impeller. This tends to form in liquids of any viscosity as they are being transported through and around a pump system. When each of these tiny bubbles collapses or bursts, it creates a high energy shock wave inside the liquid. Imagine throwing a stone into a pond. The circular ripples which are created in this process are similar to cavitation bubbles exploding. The difference here is that due to the sheer number of bubbles creating these shock waves, the impeller and other pump components can be eroded over time.

Types of Cavitation
There are five different types of cavitation. It is important to understand these for when we look at ways to prevent cavitation from happening.

The cavitation types are:

1. Vaporisation: Also known as inadequate NPSHa cavitation or ‘classic cavitation’, this is the most common form. It occurs when a centrifugal pump imparts velocity on a liquid as it passes through the eye of the impeller. If the impeller isn’t functioning correctly, some of the liquid may be boiled quickly (vaporised), creating those tiny shock waves we discussed above.

...

4. Internal Re-circulation: In this instance, the pump cannot discharge at the proper rate and so the liquid is re-circulated around the impeller. The liquid travels through low and high pressure zones resulting in heat and high velocity. The end result? Vaporised bubbles. Common cause for this, is when a discharge valve has been close while the pump is running.

5. Air Aspiration Cavitation: Another common form. Air can sometimes be sucked into a pump through failing valves or other weak points such as joint rings. Once inside, the air has nowhere to go but along for the ride. As the liquid is swished around, the air forms bubbles which then gets popped under pressure by the impeller.

So for what I was talking about, the vaporization and following collapse is much more likely to occur under conditions where the system is inadequately pressurized (leaky cap) and hot, so that conditions entering the pump are already closer to boiling than they should be.

freedom_in_4low · May 15, 2023

Bigmac said:
Interesting. Could have been neglect by a previous owner. When I got it, it had a Griffin aluminum radiator. part of the build was replacing with a mopar and a full coolant flush and refill, water pump was not replaced though.

Is it back together yet? Any change? I have to think that erosion would impact the flow rate but no idea if it's enough to see on your temp gauge. Though might be hard to tell, if your weather has been anything like OKC this week it's been pretty cool and just raining. All. The. Time.

Bigmac · May 15, 2023

freedom_in_4low said:
Is it back together yet? Any change? I have to think that erosion would impact the flow rate but no idea if it's enough to see on your temp gauge. Though might be hard to tell, if your weather has been anything like OKC this week it's been pretty cool and just raining. All. The. Time.

Yeah it has been some wild weather for sure. No I haven't been able to get it back together yet... I figured I needed to go ahead and reseal the timing cover while I have it all apart. And if Im pulling the cover...

So while I've had the cooling parts on the bench for 7 months, I'm now waiting on a timing set and gaskets. It just never ends.

Im sure this beautiful brand new Mopar water pump will make a difference though.

Bigmac · May 27, 2023

Timing chain replaced, timing cover cleaned up and all seals replaced, new harmonic balancer, new water pump, new thermostat, new radiator cap, all new hoses, new constant tension clamps,new fan clutch and filled fully (for now) with all distilled water.

Not leaking a drop anywhere.

I'm going to order a new bottle of thermocure for some remaining surface rust in the block as I didn't leave the last application in long enough.

Ran around 190 200 for test drive last night but it was also just 65 degrees out. The real test will be in the next month or two when it gets up to 100 out.

Interesting finds during water pump replacement

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