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Water pumps

18K views 114 replies 24 participants last post by  CURLY 
#1 ·
At what mileage did you need a new waterpump? I'm replacing the fans and have a clean shot at the waterpump now. 130,000 miles plus. New dealer part or aftermarket?

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#2 · (Edited)
At what mileage did you need a new waterpump? I'm replacing the fans and have a clean shot at the waterpump now. 130,000 miles plus. New dealer part or aftermarket?

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Why waste the money. The pump will let you know when the seal is compromised by starting to dribble from the bleed hole.

The idea of replacing parts just for the sake if it has zero merit. No other discipline replaces serviceable parts...just for the purpose of replacement under the mistaken idea that a new part somehow has more integrity.

If its working fine / serviceable...leave it be.
 
#3 ·
If it was me, and I was already in there, I would just replace it. Is there 10k miles of life left or even 20k? Who knows, but certainly there is 100K+ of life in the brand new one. If you do it now it likely won't be failing in a few months on your way out of town with the family.

To my way of thinking, an old part with 130k miles on it will have less integrity than a new part with no miles.
 
#4 · (Edited)
If it was me, and I was already in there, I would just replace it. Is there 10k miles of life left or even 20k? Who knows, but certainly there is 100K+ of life in the brand new one. If you do it now it likely won't be failing in a few months on your way out of town with the family.

To my way of thinking, an old part with 130k miles on it will have less integrity than a new part with no miles.
Brand new parts possess absolutely zero integrity.
 
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#5 ·
I'd change it. Why not, you're right there. Cost for pump isn't bad, if it were me, dealer part.
 
#6 · (Edited)
How, or what makes a brand new part better than one that is demonstrating serviceability and integrity?
 
#7 ·
how, or what makes a new part better than one that has demonstrated serviceability?
You must be an engineer? Does someone really have to explain to you that parts wear out?
 
#9 ·
You are right. Why change a part if it isn't broken? He is not randomly picking a part and saying; "I think I'll change this" and tear the car apart for no reason. He has the fluid drained and radiator out, water pumps fail, it's a know fact. Why go through the trouble of tearing the car apart again when he can replace it now.
 
#10 · (Edited)
I hear what you're saying; what then if the new part fails right away, or 100mi later, or 1000mi later? How does this compare to a part that has an excellent / unblemished service history showing no sign of failure...and was removed on the premise it might fail?

A lot of this emotionally-driven wasteful behavior has been generated over the years by unscrupulous garages and dealerships. It preys on people's fears by simply planting the seed that "it could fail, so you're better off replacing it now". Or simply(!) a baseless notion that "new" implies better / superior / virgin-like / <place adjective here>

Its bullsh!t, always has been.

The amount of serviceable parts that have been thrown away (or worse - kept and installed on other customer vehicles) and the significant addition to a / any company's bottom line that is easily classified as theft from customers (successful court cases to-boot) has been a going concern for a very long time.

The new ZF transmission is not meant to be serviced; this is driving customers nuts cause they, in their infinite wisdom(!) believe the fluid should be changed at some sort of interval that soothes their touchie-feelie soft spots. No basis in logic or fact...just the notion "well - gee - THAT can't be right".

If people want to replace working parts cause they believe they are adding some sort of security or integrity is simply false. Do it cause it makes you feel good...but don't for a second believe you've delayed some sort of potential failure.

Edit: when I used to have a shop performing repairs, I always bagged the parts and gave them to the customer when they paid their bill. It demonstrated that the parts called out on the WO as being replaced were in fact replaced. It also generated a sense of honesty on my part. One time, a customer recommended me to someone who brought their vehicle in for repair, I replaced parts, gave the broken ones back...a few days later he challenged me that the parts were not from his vehicle. He attempted to litigate...guess how that turned for him.
 
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#13 · (Edited)
Money would be better (slightly) spent on a lotto tickets :^D
 
#14 ·
This discussion on passive / active part performance / integrity / replacement occurs elsewhere / periodically and the same anchoring (focalism) bias plays out in precisely the same manner every time. Reasonable folks look for evidence by taking the time to rationalize - prior to decision-making; it can be an eureka moment.

I'd bet real money though - most people will not be able to resist their emotional attachment / cognitive bias and replace parts willie-nillie :^D
 
#15 ·
If you focus on the water pump only. When you replace it what about the o-ring behind the timing cover? It gets disturbed when the pump is taken off. So why not take the timing cover off to replace that o-ring.
Then while you're in there, hmm theres the timing chain and tensioner, should you replace that too?

Why put a new pump on and have that o-ring leak...

When I rebuilt my engine it had a newer pump on it. I replaced it only because there are two types of o-rings for the pump and no parts stores from Advance auto to Napa stock the correct one. They all have the other one.
So I got a new pump with a new o-ring, this o-ring also fit my old pump.

And if you do the pump should you be like the ford guys with the 302 or 351 and replace the water pump bolts even though theres nothing wrong with them.... you gotta replace the bolts.... with ARP stainless.
 
#17 ·
If you focus on the water pump only. When you replace it what about the o-ring behind the timing cover? It gets disturbed when the pump is taken off. So why not take the timing cover off to replace that o-ring.
Then while you're in there, hmm theres the timing chain and tensioner, should you replace that too?

Why put a new pump on and have that o-ring leak...

When I rebuilt my engine it had a newer pump on it. I replaced it only because there are two types of o-rings for the pump and no parts stores from Advance auto to Napa stock the correct one. They all have the other one.
So I got a new pump with a new o-ring, this o-ring also fit my old pump.

And if you do the pump should you be like the ford guys with the 302 or 351 and replace the water pump bolts even though theres nothing wrong with them.... you gotta replace the bolts.... with ARP stainless.
No because the FSM doesn't say it needs replacement with water pump R&R...at least on the 5.7. Not sure if we are talking the same engine?
 
#16 ·
See I have worked for a local city as the diesel mechanic for many years and my primary Vehicles were Rescue Squad fire trucks and police cars. So the way the City Works if I was replacing the water pump then it got new hoses and anything within reach was replaced. Therefore my question and was trained that way sort of (Company Policy)

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#18 ·
See I have worked for a local city as the diesel mechanic for many years and my primary Vehicles were Rescue Squad fire trucks and police cars. So the way the City Works if I was replacing the water pump then it got new hoses and anything within reach was replaced. Therefore my question and was trained that way sort of (Company Policy)

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I can't argue with that policy....and honestly if the hoses are over 5+yrs I might replace them too....Some of it comes down to how hard they are to access/replace.
 
#20 ·
The statement that there is no precedence for this and that no other discipline does this is not really correct. I used to be in the truck rental and leasing business, and there are lots of parts replaced due to mileage intervals - whether they show signs of failure or not. It's less expensive in the long run to replace the part when the truck is in for regular service, than have it down on the side of the road. And then there's that other discipline called airplane maintenance - they certainly replace parts before they wear out! I know it's not a fair comparison (airplanes vs. autos), but this practice IS done in other maintenance disciplines.
 
#24 ·
I remember the day I started as a city mechanic and the fire chief came down to meet me and he put his finger in my chest and said my guys can only do their job if they can get there, and he said keep it like new and ready to roll!

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#27 ·
You are right in that there is a normal life-span for mechanical assemblies...they would follow what is called the bathtub curve.
That is a high fail rate likely very early on in its life, due typically to manufacture error/piece part failure...then failures fall to very low over its normal life span and then rise again as the component reaches end of life as piece parts fail.
Now what is considered normal life span is a question for the manufacturer and what they have designed it to be.
I'm sure they didn't design the 4.7L water pump in my '01 Durango to go over 300K miles...yet it did, so an outlier?
Conversely we know the pump that failed in my '14 Hemi certainly was designed to last longer than 2 yrs and 38,000 miles and to that FCA extended the water pump warranty on my '14 to 7 yrs, 150,000 miles. So I would take that as the average expected lifespan designed into the factory water pump.

As Hemissary is pointing out a water pump or component that has been running fine for say a couple of years or even a few years has better odds of providing reliable service than a brand new part...as the new part could have a failure early on.
Happened to me with a Mitsu 4G63 engine, I replaced a perfectly fine water pump as I was replacing the timing belt and I was already in there. Well the new pump had a defect and failed within 1,000 miles. I got a replacement for free under warranty...but still had to go through all the labor again to replace and on a 4G63 engine, that is a pain!
Also a lot of components do give some warning of failure prior to complete failure. Water pumps for example either leak from seal going bad or squeak as bearing starts to fail. You should have plenty of warning of impending water pump failure.
 
#28 ·
I have a pump and hoses in my inventory of parts. I bought them to make sure I had them if and when a failure occurred. Well that was 5 years ago and they are still on the shelf. Don't change parts for the sake of changing them but if you are concerned about failures, buy the part and shelve it.
 
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#29 ·
The exception to this thinking is the air line industry where they replace parts when they reach a point in their "normal" service life. That is one reason airplanes are so reliable. That is also the practice in nuclear power plant maintenance. Many critical parts are not "run to failure" If a part can fail and shut down the power plant or if it is a safety related part, it's replaced before its normal life time. Seal failure and pump impeller erosion is a concern on some cars, maybe not on ours.
 
#30 ·
Agree aviation is a bit different especially when you are 30,000 ft above the ground in something that doesn't really glide all that well if it loses power.
At least in a car you can pull to the side of the road without much drama.
Fleets can have the same advantage...where you know the normal service life of components and can then be proactive in component repair and replacement before having an actual failure.

I ran the tensioner beyond the factory recommended 100K change interval and it finally failed very close to 150,000 miles. Problem was I was an hour away from home and had to do a road side repair as the pulley locked up from bearing failure. Annoyingly it did not provide any real notice of impending failure.
So I now follow the 100K change interval for that and the idler pulley.
 
#34 ·
I guess there really is no right answer. It is a different philosophy on each hand so now I'm really f---ing confused. No just kidding I am curious to know about the gasket behind the water pump that Hemissary spoke of is that the cover over the timing gear and chain?

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#36 · (Edited)
I guess there really is no right answer. It is a different philosophy on each hand so now I'm really f---ing confused. No just kidding I am curious to know about the gasket behind the water pump that Hemissary spoke of is that the cover over the timing gear and chain?

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Try and resist the urge to waste money on a baseless notion that somehow you're doing yourself a favor by replacing parts that are demonstrating their serviceability.

Hemissary, I've not seen a recommended mileage for replacement of the tensioner or chain on the 5.7 (I assume mine has the standard tensioner, since I've owned it since almost new, and haven't changed it) - what is the recommendation for doing that, and should the chain be replaced as well?
Tough to answer. I know that if I open up the front of my engine I will be carefully inspecting up close the modifications I performed in order to deal with what I believe is first based on engine rpm changes that causes the main tensioner assembly to flex that then causes the end of the leaf spring fingers to dig into the bottom NYLON stops / retainers molded into the tensioner. Eventually, the leaf springs work through and drop down causing the upper fingers to depart their(!) securing stops.

Once this happens dynamic chain tension is significantly less or zero, exacerbating the flexing action due to chain whip. The leaf springs, now loose and able to disassociate themselves from the tensioner then get caught in the chain / lower crankshaft drive gear that destroys them. This action puts an increased (unknown magnitude) load on both front cam / crank bearing interfaces as (spring steel) leaf spring debris is compressed between the chain and the gear assembly.

I've had someone else's engine apart that has experienced this failure mode. At least on that engine's bearing interfaces, there was no visible or measureable changes. So it appears to be enough chain slack - once the tensioner fails - to absorb the loading when leaf spring debris is broken up by the chain / gear interface.

Aftermarket camshafts with significantly more aggressive ramps and lift vectors automatically increases flexing at the tensioner. This accelerates those leaf springs ability to cut into their bottom stops.

The question is why some engines modded or not modded (untouched OEM engines) - might or might not experience this type of failure mode. The main uncontrolled variables are spring steel leaf spring Quality Control (proper percentage of low manganese / medium to high carbon steel alloys, proper heat treating, curvature versus loading), aftermarket camshafts that exacerbate the issue, where in the rpm range engines spend most of their time (idle / lumpy idle being the worst case scenario).

As to chain wear; under normal circumstance is a non-issue. OEM camshaft chains are over-built to start with, especially given they are turning a camshaft with rollers. A long time ago I saw someone try to explain away a used chain that would become stiff and / or jam up when flexed in the opposite direct to normal operation. That in very simple terms is grossly misleading. So the chain along with drive / driven gears should be fine.

If you have the timing cover off for any reason, I suggest looking VERY closely at the leaf springs and where they are captured by the NYLON tensioner. If you see any evidence of NYLON material being carved out, replace it. Note that you can remove the leaf springs from the tensioner to have a proper looksee.

Otherwise, given the known issues / failures with pre-08' tensioners, replace the entire tensioner assembly.

I cant tell you when. Its more difficult when it is a lengthy process to inspect. I modified my timing cover to allow me to look inside anytime I want with a boroscope: GEN III Inspection Ports (so far - so good).
 
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#37 ·
This thread is exactly why I don't even ask questions. The water pump is $85 for one made in china, or you could probably order an OEM one from the dealer thats probably made in china also but two or three times the price and they don't have it in stock.

It's amazing how stupid education can make people. Can't stay focused on the "should I replace the water pump" part, we just have to go off on how "we" do it in the aerospace industry and "our" theories.

How about referring to the automotive industry, since it is, well, a car we're talking about.
 
#39 ·
This thread is exactly why I don't even ask questions. The water pump is $85 for one made in china, or you could probably order an OEM one from the dealer thats probably made in china also but two or three times the price and they don't have it in stock.

It's amazing how stupid education can make people. Can't stay focused on the "should I replace the water pump" part, we just have to go off on how "we" do it in the aerospace industry and "our" theories.

How about referring to the automotive industry, since it is, well, a car we're talking about.
The guy asked for opinions and that is what he got. There is no "correct" answer, just opinions.
 
#38 ·
Yeah the ridiculousness is mind boggling. I wonder why the car manufactures haven't figured out that they can start sending out "proven" parts, for warranty, stripped from wrecked junkyard cars. These are surely better than the expensive new parts they are currently installing! Why are they supplying new intake gaskets etc on their warranty jobs?

The reality is that the car manufacturers install cheap parts so that the majority are expected to last, only as long as the warranty is in place, with an acceptable, and expected, defect rate. The cheap water pump bearings fail and the lip seals in the pumps fail. Fact. Who knows when either will occur. Some people drive their new car off the lot and never have any problems. Others are back at the dealer for repairs weekly.
 
#40 ·
Yeah the ridiculousness is mind boggling. I wonder why the car manufactures haven't figured out that they can start sending out "proven" parts, for warranty, stripped from wrecked junkyard cars. These are surely better than the expensive new parts they are currently installing! Why are they supplying new intake gaskets etc on their warranty jobs?

The reality is that the car manufacturers install cheap parts so that the majority are expected to last, only as long as the warranty is in place, with an acceptable, and expected, defect rate. The cheap water pump bearings fail and the lip seals in the pumps fail. Fact. Who knows when either will occur. Some people drive their new car off the lot and never have any problems. Others are back at the dealer for repairs weekly.
Irrational and hyperbole. :panic:
 
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