Water Pump and Alternator Advice Needed

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Boggie
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Water Pump and Alternator Advice Needed

Post by Boggie »

Evening all,

Currently the car has good but unknown age water pump and alternator. Whilst I have the plenum removed to fit new BMW hoses and clamps it is easy to get to both. Well, I say easy but it seems the only way to remove the alternator is to first remove the oil cooler feed pipes. I can loosen the large nuts but the pipes coming through the nuts are seemingly bonded to them with age so I cannot get the nuts turning to remove the pipes. I have been soaking them with penetrating oil for a couple of days but no joy yet. Any tricks that might help please?

I guess my real question (assuming I get the oil feed pipes free) is whether I should replace the pump and alternator. As I said, they are both working well but as I like to fit genuine parts I am looking at over £500 to replace both. Can anyone recommend high-quality non-genuine alternatives I should consider or are genuine parts the only way to go? Or should I leave them until they fail at some point in the (potentially long) future? I plan a big road trip to the Alps with the family later in the summer so need the car to be reliable....

Thanks,
Ian
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Brucey
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Re: Water Pump and Alternator Advice Needed

Post by Brucey »

IIRC an M30 water pump will fit M88 and costs little (I bought a perfectly serviceable pattern pump for less than £20 a few years ago).

If the oil pipes are not playing ball, you could remove the entire oil filter assy from the side of the block instead.

FWIW the part that is most likely to fail in the alternator is the brush/regulator unit. Again this is easily replaced and in fact you could do yourself a favour and fit one with a higher voltage rating (eg 14.2V rather than 13.8V) and this will mean that a modern battery (with calcium chemistry) will take a full charge.

Use a mechanic's stethoscope to verify that the bearings are OK and if so you can fairly safely assume that once fitted with a new regulator the alternator will carry on working for some time to come.

cheers
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

That's a good info, thanks Brucey. I will have a listen to the bearings with my stethoscope but when the engine was running there was no noticeable sound. Also, fitting a regulator will give me a set of brushes into the mix. Can this be done with the alternator in situ?
I have removed and cleaned all the connections and fitted new stainless nuts and washers so they won't corrode. I will stick on a new suppressor whilst I have access.

On the water pump: it it is not leaking and quiet I might leave it. Getting the pump off looks like a radiator out job due to fan clearance.

Cheers,
Ian

PS: Oil pipes let go of the nut with a little application of heat from my torch.
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raykoke
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Re: Water Pump and Alternator Advice Needed

Post by raykoke »

My alternator bearing(s) had been complaining for years. Determined by a liberal spritz of oil to the location while running.

I pulled the alternator for bearing replacement when the water pump went last year, original pump and 82k miles. I had no issue with oil cooler lines in the way. Maybe I better look and see if the cooler is still there! :o Oh wait, is your steering wheel on the wrong side? :) Maybe that contributes.

I installed a Graf M30 water pump; no issues. Upon recommendation I used Permatex The Right Stuff, and no paper gasket.

Good luck with yours.

Cheers,

Ray
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Pod
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Re: Water Pump and Alternator Advice Needed

Post by Pod »

If you’ve got the alternator off, why not change the two mounting bearings? They will eventually wear and cause the alternator/pulley to move out of line.
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

raykoke wrote: Tue Mar 06, 2018 12:32 am My alternator bearing(s) had been complaining for years. Determined by a liberal spritz of oil to the location while running.

I pulled the alternator for bearing replacement when the water pump went last year, original pump and 82k miles. I had no issue with oil cooler lines in the way. Maybe I better look and see if the cooler is still there! :o Oh wait, is your steering wheel on the wrong side? :) Maybe that contributes.

I installed a Graf M30 water pump; no issues. Upon recommendation I used Permatex The Right Stuff, and no paper gasket.

Good luck with yours.

Cheers,

Ray
Last time I checked my steering wheel was on the 'right' side.... :)
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Pod wrote: Tue Mar 06, 2018 6:32 am If you’ve got the alternator off, why not change the two mounting bearings? They will eventually wear and cause the alternator/pulley to move out of line.
Ah haa! So that's why... I was looking at identify the belts I need and noticed the alternator pulley was out of line and was planning on investigating. You saved me the trouble, Thanks!
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Brucey
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Re: Water Pump and Alternator Advice Needed

Post by Brucey »

Boggie wrote: Tue Mar 06, 2018 12:00 am That's a good info, thanks Brucey. I will have a listen to the bearings with my stethoscope but when the engine was running there was no noticeable sound. Also, fitting a regulator will give me a set of brushes into the mix. Can this be done with the alternator in situ?
yes. If the old brushes are not worn evenly it is normal for the one closest to the bearing to be a little more worn; this usually signifies that grease has migrated from the tail bearing.
On the water pump: it it is not leaking and quiet I might leave it. Getting the pump off looks like a radiator out job due to fan clearance.
Water pumps seal via seal ring that sees higher load (and seals better) when the system is pressurised. A common fault is that the system sees negative pressure when it cools down (eg because the negative pressure valve in the rad cap is sticky) and the systems draws air in through the water pump as it cools down instead. This is often accompanied by a tiny weep of coolant through the water pump, because the seal doesn't immediately re-seat itself perfectly. Any water passing the seal usually goes through one bearing (of two) before it drains out of the bearing housing. Thus the most common pattern of water pump failure is that the block side bearing starts to run rough and once there is enough movement in it the seal cannot work correctly and the pump wills soon fail.

So if you are to carry on with an old water pump

a) check that the low pressure valve in the coolant system cap is free to move (it should open at ~2psi neagtive) and
b) check for any signs of weeping having occurred under the water pump and
c) check the bearings (eg using a stethoscope) to see if they are already running rough or not.

Yes changing a water pump is a PITA but it is much less of a PITA than having one fail in service; if there is any doubt regarding its condition and you are in it for the long haul, change it.

cheers
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Brucey
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Re: Water Pump and Alternator Advice Needed

Post by Brucey »

re the alternator, yes the rubber mountings are liable to collapse over time. A common modification is to change the rubber mounts for aluminium ones (see e-bay).

Later M30 engines had a revised mountings and I think these (or similar) were used/will fit on M88 engines too.

The full monty comprises a different alternator with solid mountings (no rubber bushes) and a double-sided upper tensioning bracket, all of which is fitted to a slightly different accessory frame (the aluminium piece that carries the PAS pump and the alternator). The double-sided bracket helps to stop the alternator from twisting.

It is usually possible to fit various combinations of parts such as a solid mount alternator and/or a double-sided tensioning bracket to older engines, provided you are happy to carry out some small modifications (eg drilling and tapping the accessory frame slightly differently) if necessary.

One of my cars has a double sided tensioning bracket fitted to a 1985 car using all the original parts apart from a couple of bolts. This makes the movement of the (rubber mounted) alternator less than half the usual amount. The bracket was taken from an E34 and needed a small modification to fit.

cheers
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

As ever Brucey, good advice. Whilst the pump is a PITA to change, I currently have the cooling system drained and most of the water pipes off so I guess now would be a good time for preventative maintenance. Any recommendations from you on the best after-market pumps to go for? I cab get the Graf Ray recommends for about £30 or a Magnetti Marelli for around £50 from AutoDoc

Alternator mountings are a bit of a minefield. As far as I can see from RealOEM (PAGE1 and PAGE2) there are choices:

TOP RUBBERS (2 required)
12311268447
OR
12311268433

BOTTOM RUBBERS (2 required)
12311268447
OR
12311268433

TOP/BOTTOM TUBES (2 required)
12311276227

Any easy way to ID which rubbers to get? There are no specifications I can see to help me choose...
I guess I could order 4 of each (but that's £40 wasted) OR perhaps make some on the lathe out of ally bar.

Cheers,
Ian
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Brucey
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Re: Water Pump and Alternator Advice Needed

Post by Brucey »

I am not familiar with the different variations in rubber mounts; I suppose that they might be to fit different alternators. Different alternators were fitted were fitted over time and to different models of E24 depending on regional variation and equipment level.

If you have a lathe, you are guaranteed to be able to make something that fits perfectly!

BTW some Bosch voltage regulators won't fit some Bosch alternators; the screw mountings are common but the regulator housing fouls on the body of some (early) alternators, where the tail bearing is mounted within the casting. It is usually possible to file the plastic housing of the regulator to overcome this.

Regarding water pumps they seem to be much of a muchness; good modern ones will have pressed steel impeller (rather than a cast iron one). I think that you are unlikely to be offered one with a plastic impeller but if you are, steer well clear!

The pressed steel impellers look crude but they seem to work OK; in theory a carefully shaped impeller might be more efficient, but this improved efficiency is likely to occur only under a narrow range of flow conditions, that will only exist when the tstat is open a certain amount and the pressure drop in the radiator is within a certain range.

cheers
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Thanks Again Brucey.

I think I will order the more expensive pump as they are not expensive (esp. compared to original BMW items) and I know Magnetti Marelli components are well made.
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brickwhite
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Re: Water Pump and Alternator Advice Needed

Post by brickwhite »

I always use HEPU water pumps.

https://www.fcpeuro.com/products/bmw-wa ... 1519070761

pn - 11519061160 / 11519070761
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Hepu are German too....
:)
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Brucey wrote: Tue Mar 06, 2018 10:05 am I am not familiar with the different variations in rubber mounts; I suppose that they might be to fit different alternators. Different alternators were fitted were fitted over time and to different models of E24 depending on regional variation and equipment level.

If you have a lathe, you are guaranteed to be able to make something that fits perfectly!

cheers
Nearly £90 for 4x rubber bushes from BMW!! Forget ally, I am going to machine them from titanium....
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GRNSHRK
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Re: Water Pump and Alternator Advice Needed

Post by GRNSHRK »

Regarding the alternator bushings, BavAuto here in the states offers a urethane version, I've been using these virtually for ever and they simply do not wear out [-X

https://www.bavauto.com/engine-drivetra ... _name=8035

Gonna cost ya nearly $90 USD as well, unfortunately #-o
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raykoke
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Re: Water Pump and Alternator Advice Needed

Post by raykoke »

Foraging here may be cheaper. Or worse! ;)

https://www.ebay.com/sch/i.html?_from=R ... sacat=6000

Cheers,

Ray
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Oooooh thanks Chaps!
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Re: Water Pump and Alternator Advice Needed

Post by brickwhite »

- 12 535i
- 92 325ic
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Boggie
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Re: Water Pump and Alternator Advice Needed

Post by Boggie »

Wow, that is a LOT cheaper than the UK price but I believe that exclusively for the UK market, BMW include a free signed picture of Beyoncé, naked and riding a unicorn around Brooklands race track... :)
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