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E90/E91/E92/E93 (2006 - 2013)
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  #26  
Old 09-20-2018, 03:20 AM
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I have 162,000 miles on my original water pump so far.
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  #27  
Old 09-20-2018, 05:46 AM
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Water Pump Failure

i know, as they say, that "Your Mileage May Vary". If mine had lasted even 60,000 mi. I wouldn't feel quite so bad, but 32,500 is punitive. especially when it costs around $1000 to have it replaced. There was a time when I would have replaced it myself, but I'm past that age. I get sticker shock every time I have to pay to have something repaired when I know how to do it myself. Another of the indignities of old age.

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Old 09-20-2018, 12:07 PM
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I'm at ~53K miles. I was going to have mine changed out as a preventative maintenance item this year at the dealer, but that plan fell apart because some other things came up unexpectedly. I'm putting it off for now, but in any case, if it doesn't fail prematurely on me, I will be replacing it between 60K and 70K miles for sure. I was told that no codes were found in relation to the cooling system, although I know that these pumps "just fail" from one second to the next, hence the planned replacement as a maintenance item.
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Old 09-20-2018, 03:44 PM
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  #30  
Old 09-21-2018, 09:19 AM
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My current 335i had the water pump fail at 92,000. My previous 335i had its water pump fail at 101,000.


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  #31  
Old 09-21-2018, 10:52 AM
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Water Pump Failure

Am I just old fashioned, or am I the only one who thinks $1000+ to replace a water pump is obscene?

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  #32  
Old 09-21-2018, 10:57 AM
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Am I just old fashioned, or am I the only one who thinks $1000+ to replace a water pump is obscene?

LTQl
It's a different kind of water pump. You're probably used to the mechanical ones. The ones BMW uses are electric. The physical part cost a lot more.

Random comparison:

2011 Ford Focus water pump: $28.74
2011 BMW 328i water pump: $412.30

I actually don't know what the difference in labour is, but I do believe it's a few more hours to get it done on the BMW as well.

That's the main reasons for the cost difference.
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Old 09-21-2018, 11:15 AM
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There are also extreme storage, handling and installation requirements for the Graphitar journal bearings in an electric coolant pump. Ignoring these precautions is what damages and shortens their life.
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Old 09-21-2018, 11:16 AM
quiett quiett is offline
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Water Pump Failure

I understand that the electric pump may cost more than a simple mechanical one, but $4-600? And yes, the labor may be more, but still. I think the BMW premium has been at work. I'm paying it, but I don't have to like it. Even my Porsche isn't that overpriced, and they know haw to overcharge, too. .

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Old 09-21-2018, 01:45 PM
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Quote:
Originally Posted by quiett View Post
I understand that the electric pump may cost more than a simple mechanical one, but $4-600? And yes, the labor may be more, but still. I think the BMW premium has been at work. I'm paying it, but I don't have to like it. Even my Porsche isn't that overpriced, and they know haw to overcharge, too.
Yeah, I don't disagree. The part itself seems to be fairly expensive.
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Old 09-21-2018, 02:02 PM
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Water Pump Failure

I guess that's why they are so durable.

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  #37  
Old 09-22-2018, 08:19 AM
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I imagine the purpose of this thread and others are in hope of trying to establish a baseline MTBF for the water pump in the e9x (N5x engine) models and to estimate a periodic maintenance schedule for replacement that is less than the average MTBF?

I've read through many of them and WP failure surveys and there seems to be a big disparity regarding when these fail. On prior BMW's with mechanical water pumps (i.e. m5x) it was commonly accepted that a prudent replacement interval was 4 years or 60k-mi. If you kept that schedule you were unlikely to experience any issue with a failing water pump, or so it was believed.

This does not seem to be the case with this electric water pump used on n5x engines. I've read many instances of pumps failing with as little as 30k-mi and less. I also have no confidence in published replacement schedules such as that offered by BAV Auto that state 6 years or 100k-mi as an expert recommendation. I'm sure many n5x electric water pumps might exceed that 6yr/100k-mi period but my first hand knowledge (I might've changed more Piersburg wp's than Saleri/Wahler in the past decade) and the thousands of posts/threads and articles online suggest a high percentage of the electric water pumps don't get anywhere near that 100k-mi replacement mark.

I'm also not a fan of the DME logic for handling water pump failure - if the deviation of requested/actual speed hits a defined counter, DME shuts down the water pump - that's it you're stranded - wherever. I had this happen to me (well nearly). I was able to clear the DME WP Shutdown error on the roadside (thus allowing the water pump to resume operation even if it was lower efficiency) and modify load conditions to allow the failing water pump to work enough to get me home, albeit uncomfortably (AC=OFF, heat=high, speed/load minimal) For my self created limp mode drive home the Coolant temp never exceeded 98C but the temp in the cabin did . The water pump ran slower than requested - but enough to drive 20 miles.

When I got the car home I replaced the water pump and thermostat (seeing I had spares in my garage).

There might not be a commonly accepted MTBF (lifespan - age or mileage) for these water pumps but they do exhibit a common failure characteristic that might be used as a PM replacement signal - that is a steadily increasing RPM deviation from actual to requested speed.

There may be other signals such as an increase in power consumption but I have not noted that yet.

I resolved myself to making a check of the water pump operation on a monthly basis a part of the vehicle maintenance schedule. It will at least let me store data over a period of time where I can see the efficiency of the water pump degrade. I'm hoping it allows me to determine when I will need to replace the pump before it fails. Takes 5 mins to run the engine at various revs and log the wp data to see how it is performing.

Many will see this as a true anal enthusiast approach, perhaps, but it's certainly something I will be checking on any of my n5x equipped vehicles with electric water pumps before I take them on a long trip.


Last edited by BMW-North; 09-22-2018 at 08:21 AM.
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  #38  
Old 09-22-2018, 11:52 AM
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Quote:
Originally Posted by BMW-North View Post
I resolved myself to making a check of the water pump operation on a monthly basis a part of the vehicle maintenance schedule. It will at least let me store data over a period of time where I can see the efficiency of the water pump degrade. I'm hoping it allows me to determine when I will need to replace the pump before it fails. Takes 5 mins to run the engine at various revs and log the wp data to see how it is performing.
What software / application are you using to see the parameters you posted ?
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Old 09-22-2018, 01:44 PM
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What software / application are you using to see the parameters you posted ?
Sorry - should have included that - Done using Carly (not really a fan of the app but for BMW specific PID's & portability it's tough to beat).
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  #40  
Old 09-23-2018, 11:30 AM
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Sorry - should have included that - Done using Carly (not really a fan of the app but for BMW specific PID's & portability it's tough to beat).
From the colour-scheme I assumed it was Carly, but didn't want to look dumb or anything

This is super interesting - I'm going to test this with my Carly and see what it comes up with.
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  #41  
Old 09-23-2018, 12:56 PM
gbalthrop gbalthrop is offline
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Suggested Coolant Pump Tests & Sharing of Data

Quote:
Originally Posted by BMW-North View Post
...[1] estimate a periodic maintenance schedule for replacement that is less than the average MTBF? (Mean Time Between Failures)...there seems to be a big disparity regarding when these fail...I also have no confidence in published replacement schedules such as that offered by BAV Auto that state 6 years or 100k-mi as an expert recommendation...
[2] I'm also not a fan of the DME logic for handling water pump failure - if the deviation of requested/actual speed hits a defined counter, DME shuts down the water pump - that's it you're stranded - wherever. I had this happen to me (well nearly). I was able to clear the DME WP Shutdown error on the roadside (thus allowing the water pump to resume operation even if it was lower efficiency) and modify load conditions to allow the failing water pump to work enough to get me home...the Coolant temp never exceeded 98C...The water pump ran slower than requested - but enough to drive 20 miles.
[3] There might not be a commonly accepted MTBF (lifespan - age or mileage) for these water pumps but they do exhibit a common failure characteristic that might be used as a PM replacement signal - that is a steadily increasing RPM deviation from actual to requested speed. There may be other signals such as an increase in power consumption but I have not noted that yet.
[4] I resolved myself to making a check of the water pump operation on a monthly basis a part of the vehicle maintenance schedule. It will at least let me store data over a period of time where I can see the efficiency of the water pump degrade. I'm hoping it allows me to determine when I will need to replace the pump before it fails. Takes 5 mins to run the engine at various revs and log the wp data to see how it is performing. Many will see this as a true anal [Read ANALytical ] enthusiast approach, perhaps, but it's certainly something I will be checking on any of my n5x equipped vehicles with electric water pumps before I take them on a long trip.
ISSUES & QUESTIONS:

(1) It appears that there are too many variables to have any reliable mileage/age MTBF (Mean Time Between Failures) value that ALL E9x owners, regardless of their personal technical ability and available diagnostic tools can apply. Mode and time of failure for particular pump, for particular engine, by particular part manufacturer for particular driving and ambient conditions, etc. obviously varies, as does the ability of each owner to test & diagnose degrading pump operation prior to shutdown. So, for those who are looking for a quick, simple, one-size-fits-all ANSWER to the question as originally posted nearly 5 years ago, just consult your local BMW Dealer.

(2) So, Questions for those who diagnose &/or maintain their own cars should be:
(a) HOW can/should I monitor my Coolant Pump Health?
(b) HOW can I determine what caused SES/Overheat Light or Pump Shutdown?
(c) HOW/CAN I get the pump to run (safely) long enough to get home?
(d) WHAT is SAFE mileage or running time to use that method -- any RISKS?
(e) IS THERE a definitive test value for impending DME Pump Shutdown?
FAILURE MODE:
Old-style mechanical "water pumps" were easy to diagnose, as the common failure mode was shaft bearing wear to the point of front shaft seal failure and leaking of coolant at that seal. So unless you never checked coolant level, or never inspected the front of the pump shaft for leaks, you knew you had a problem that needed to be fixed LONG before any catastrophic failure. In years of maintaining my own vehicles, I NEVER had any failure of a mechanical pump from bearing seizure, impeller failure, etc. which caused failure to pump coolant with resultant overheating -- ONLY leaking front seal with MONTHS or more than 1,000 miles of notice.

So the first question about Electric Coolant Pump failure should be: WHAT actually fails or prevents normal operation of the pump? External leakage from case cracks (apparently common in N54 engine pumps) of course can cause coolant leakage into the connector and prevent proper activation signal, but that does NOT seem to be the most common failure mode, at least on the N51/N52 engines.

From recent, previous discussions of this issue, it does NOT appear that the most frequently-occurring failure mode is: (i) sudden, complete electrical failure, or (ii) catastrophic internal mechanical failure, such as impeller or bearing seizure. Rather, as "North" states, there appears to be a slowly-deteriorating condition (such as resistance to impeller rotation due to bearing condition) that causes the motor to turn slower than it should with a particular control input (more load on the motor).

So, absent any actual "autopsies" conducted on old pumps removed after xx thousands of miles of use, we can only theorize as to why it quit working. Based on North's information above, it would appear that the most frequently-encountered failure mode, at least in 328i/xi vehicles with N51/N52 engines is gradual increased resistance to impeller rotation, causing "Speed Deviation" or slower Actual Pump Speed or RPM than the "Setpoint"/Requested RPM, or what the DME signal should accomplish.

Although it would be nice to know (from a theoretical standpoint) what factors, either electrical or mechanical, cause that speed deviation, we can probably devise a reliable test and Parameters for determining the threshold where the DME shuts down pump operation, or quits sending a control signal -- at least until a code is cleared.

For the Pro's who actually see failed Coolant Pumps on a regular basis, it might also be helpful for diagnostic confirmation purposes, after removal of splash shield, to listen to activated pump with a mechanic's stethoscope for any tell-tale signs of increased impeller or bearing noise. Having NEVER removed the pump or disassemble it, I can ONLY theorize, so actual experience from those who HAVE examined multiple pumps is greatly appreciated. I fully realize that the guys in the shop who are getting paid to R&R probably realize they don't get paid any more for spending time trying to "play engineer," but that is actually what we need here.

INPA/ISTA TESTS & PARAMETERS:

Since more people who do their own diagnostics probably have either or both of the above, what tests can be done using that software? I am currently using INPA, and it does NOT appear to have ANY Status(F5)/ Parameters related to Coolant Pump function, but it DOES have Activations (F6), such as Activate Coolant Pump, F6 | F1 | Shft+F1. That function does NOT display a specific RPM either for Setpoint or Actual, but it DOES provide "percentage" readouts, presumably % of max speed, with 5%, 50% and 95% Setpoint selections via F1, F2 & F3 keys (along with Bleed selection, F5), and a readout of Actual "percentage" speed (along with ECTS Temp & Radiator Outlet Temp).

ANYONE used that to obtain any "Speed Deviation" data?
ANYONE used ISTA to obtain any Speed Deviation data -- Details?

CODES RELATED TO PUMP SHUTDOWN -- HOW TO CLEAR & LIMP?

"North" has previously listed 5 BMW FC's that relate to Coolant Pump issues:
2E81 Electric coolant pump, speed deviation, speed outside the tolerance
2E82 Electric coolant pump cutoff, over-current
2E83 Electric coolant pump, power-reduced operation, dry run
2E84 Electric coolant pump, communication
2E85 Electric coolant pump, communication, no voltage at emergency operation input of pump

It would be helpful to know which of these codes indicates a condition that has caused DME shutdown of the pump due to excessive speed deviation, or resistance to rotation that causes excessive current draw (as apparently FC 2E82 does). Also do ANY/ALL of these codes cause lighting of a warning lamp, and if so, does simply allowing the engine to cool (ignition OFF) cause the warning lamp (either overheat warning light or SES) to go out, and is pump operation/control by DME restored when light goes out, or must a code be deleted?

For those of us who use INPA and a laptop for proper diagnostics, but may not always be carrying the laptop, are there equivalent P-codes that a standalone P-code reader can read/clear for each of the 5 BMW FC's listed above?

Finally, if the Coolant Pump is going to need replacement anyway if the DME keeps shutting it down, is there any risk of damage to the DME or any other component by continuing to clear the code to limp home, as long as coolant temp remains in the 100C range and the overheat warning light (~ 115-120C) does NOT come on. Engine temp can be monitored by generic scan tool or Hidden Menu 7.00.

Thanks,
George
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  #42  
Old 09-23-2018, 01:27 PM
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George - I thought my posts were long?

I'll try to answer a couple of your points. None of my remarks are scientific and based on my observations the past couple of years after I noted I was replacing electric pumps "too" often - I started looking at my own n52 equipped engines (e90x2, e92, e83) - and with those I keep detailed logs.

The only other error recorded in DME when my e92 wp was shut down by DME was an RPM deviation too great error. Now that same error had shown a few weeks prior but did not cause shutdown when it occurred. I think like emissions faults, in addition to the fault occurring (meaning predetermined severity i.e. RPM deviation > X = Fault) it has to also occur a number of times (Fault + occurrence > X) to warrant the DME reaction (shutdown). Now why DME must shut down the water-pump is probably a built-in safety to protect circuits from cooking although the fuse should do that.

There are no cluster indicators (visual or audible) for a failed/shutdown water pump. The result however will be rapidly increasing coolant temps which will likely cause related visual and audible "overheat" warnings. - However these could occur for several other reasons such as a complete coolant loss etc.

One tidbit you might find interesting is that I was doing some component testing using ISTA today on my e92. On prior occasions with the old water pump when I activated it at either speed (you have a choice of 50% or 95%) it was very audible. Today I had to use my stethascope to make sure the newer one was working (although ISTA would have told me if the response was not expected) - I couldn't hear it.

Now this is conjecture but I'm assuming either the bearing wears or the rotational resistance increases That causes the increased noise and slower than expected speed - why - don't know - inferior parts perhaps, poor design - alternators run for a very long time without issue. I'm gonna take a couple apart and see if there are any tell tale signs.
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Old 09-24-2018, 06:56 AM
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Chiming in on this old post.
Bought my 2010 E92 brand new. As of 8 years, 9 months and 103,600+ miles, don't see any signs of any possible pump failure.
My trusted mechanic flushed and checked the cooling system in 2016 and gave the A-OK.
Will have him check it again next year.
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Old 09-24-2018, 08:25 AM
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Quote:
Originally Posted by jat335i View Post
Chiming in on this old post.
Bought my 2010 E92 brand new. As of 8 years, 9 months and 103,600+ miles, don't see any signs of any possible pump failure.
My trusted mechanic flushed and checked the cooling system in 2016 and gave the A-OK.
Will have him check it again next year.
Thanks - that's just it though. There is no consistency. Like George mentioned - there are no apparent "visible" telltale signs of impending wp failure on the electric pump unlike prior belt driven versions where you could check the bearing weep hole or physically examine the pump for play. I said apparent cause I'm beginning to think that operating noise might be an indicator - too early yet though.

Belt driven pumps typically give pending failure warning via audible or physical indicators - and, they usually fail much slower. For electric WP's the DME shutoff I would suspect is the true cause of "instant failure" and immediate overheat condition. What I want to do at least for my own vehicles is determine for the electric pumps if it's feasible to rely on other information (i.e. RPM deviation logs) as early warning signs that precipitate DME shutoff (WP failure).
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Old 09-25-2018, 10:57 AM
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Mine cratered at 75k miles. I knew it was the water pump when my electric fan sounded like a jet engine.
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Old 09-26-2018, 07:26 AM
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Mine died on a 335 at 55,000 miles. I'm hoping the newer one is an updated part that will last longer. Fortunately mine died at low speed near a parking lot.
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Old 09-29-2018, 07:24 AM
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One more data point: 2009 335i WP “instant” failure at 86,500 miles / 9.5 years, the only time this otherwise fine car has let me down while on the road.

I read with interest about using the Carly app to monitor the WP parameters. I suspect the approach will be useful (although a bit too late for me!). Good work.
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Old 12-20-2018, 07:07 AM
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Here are a few more observations from a recent examination of a failed water pump. Couple of points of note.

Details of this Water Pump
The water pump was approximately 8 years old & it had approximately 40k miles of duty.
The water pump was replaced due to RPM deviation errors. It had not yet completely failed to operate.
The water pump exhibited increased "operation noise" before being replaced.
There were no signs of water egress or penetration to the sealed areas (electronics) of the pump.
The pump end shaft (opposite end from impeller) uses a graphite bearing which is more like a bushing and resembles an oversized Lifesaver (Polo mint for UK readers)
The graphite bearing is lubricated by coolant during operation to maintain a film. It is shipped with a lubricant film applied.
The electronic board inside contains a Nichicon 220µF 35V Aluminum Electrolytic Capacitor


Observations
The graphite bearing on this pump when dismantled appeared to have undergone serious stress. In addition to cracks, small chips were visible in the lubrication cavity. (See photos)
Initial testing of the Nichicon capacitor showed that it was still functioning. Further tests to confirm full compliance with stated specs are required however.

Post Dismantling Notes:
Nichicon Capacitor:
The specification for the Nichicon capacitor is 3000 hours at 105C:

In time considerations:
Operating at approx 2 hours per day would afford an intended life of @4.1 years, or
Operating at approx 4 hours per day would afford an intended life of @2 years, or

In distance considerations (no idle time):
Operating at 60mph average speed an intended life of 180,000 miles, or
Operating at 30mph average speed an intended life of 90,000 miles.
Operating at 15mph average speed an intended life of 45,000 miles.

I could not find any specification data for the MTBF or lifetime of the graphite bearing.

My examination of this specific pump and the symptoms derived prior to replacement (noise and RPM deviation) lend me to believe that this pump failed due to the graphite bearing cracking and causing the shaft to wobble slightly during rotation. This wobble might account for the increased noise and the variance from requested RPM (via DME) and resultant RPM (measured by DME).

Other Notes:
I am unsure if the dismantling caused further stress to the interference fit graphite bearing. The cracks and chipping certainly appeared to be old and not a result of the dismantling. The interference fit of the shaft to bearing was - well - nonexistent - this would permit the shaft to wobble.
I removed the capacitor to check with a multi-meter for functional operation only, I did not have tools to check for it's health and accuracy.
It would be interesting to see if the bearing could be replaced, solder back the original capacitor and test the pump again for RPM deviation and operational noise but I doubt the graphite bearing is available for sale individually?
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  #49  
Old 12-20-2018, 07:21 AM
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The plain journal bearings are a graphite alloy, no more "graphite" than iron is steel. There are many specialty Graphitar alloys.
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Last edited by Doug Huffman; 12-20-2018 at 07:23 AM.
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Old 12-20-2018, 07:26 AM
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Quote:
Originally Posted by Doug Huffman View Post
The plain journal bearings are a graphite alloy, no more "graphite" than iron is steel. There are many specialty Graphitar alloys.
The trade name is Graphitar - Made by US. Graphite. That's like saying Kleenex instead of tissue. You got nothing better to do than nit pick. Why don't you take one apart and give us your expert opinion?

The point was the bearing failed.

Here: Quoted verbatim - man you really are a complete a$$hole

GRAPHITAR® is U.S. Graphite Inc.'s trade name for a family of carbongraphite (mechanical carbon) products. U.S. Graphite traces its history
back to 1891, when the company was formed to utilize a Mexican deposit of natural graphite. For over 100 years, USG has led in the development
of mechanical carbons, from pencil "lead" to nuclear reactor components

Ref: http://www.usggledco.co.uk/About-Us

Last edited by BMW-North; 12-20-2018 at 07:45 AM. Reason: added ref
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