N52 Oil filter housing gaskets job... where to draw the line?

j24

Member
 Bristol, UK
So, I'm spamming the forum a little bit today - mainly because Autodoc has 41% off at the moment (QUICK!)

Anyway, next job for me is sorting a leak with the oil cooler/oil filter housing gaskets. I've bought gaskets for both, and now I'm torn on whether I just address the gaskets, or bite the bullet and change a few bits whilst I'm in that part of the engine...

My coupe is on just under 85k miles... so I half thought that it might make sense to install new belts/tensioner/pulleys... and then I have an even bigger question - should I be replacing the alternator??

No signs of any issues with the alternator right now, but I've seen a few accounts of it leaving people stranded by the side of the road when it fails out of the blue. I don't want to throw more money than I need to, but by the same token does it make sense to address things like the alternator, serpentine belt, tensioners/pulleys whist I'm there?

Sidenote to all of this; I'm a spanner with the spanners - managed to swap out my valve cover with help from the forum and youtube guides - but I'm very much a newbie to the N52 world and spannering in general!

So I'm torn on whether to get the gaskets done, leave it at that and don't fix what isn't broke. OR just do things whilst I'm there, install a new alternator etc, which may need doing soonish(?)

Cheers, any/all opinions are welcome!
 
While you are in there it may be prudent to do the belts, I did preventative maintenance on my N54’s water pump, the new one lasted less than a thousand miles so I’d probably leave the alternator, but others may suggest different.
 
Chippie said:
While you are in there it may be prudent to do the belts, I did preventative maintenance on my N54’s water pump, the new one lasted less than a thousand miles so I’d probably leave the alternator, but others may suggest different.

Yikes - I've also got an OE Pierburg water pump waiting to be installed as preventative maintenance! It only lasted 1000 miles?? That's a bummer. What brand did you go for?

Anyway thanks for the thoughts! Think I'll do both gaskets and the serpentine belt as a minimum.
 
I think I'd stop at belts too.
While you're in there though, take a good look at the alternator. See how the diode/brush pack attaches to the rear of it.
More often than not this is what fails and it can be changed in situ (well it can on an M54).
Handy to know for future reference.
 
It's a bit of a ballache taking stuff off, so while you're there might as well do the belts, tensioner and any pulleys. They're cheap.
I also changed the alternator while it was off, for the same reason.

I didn't do the water pump as I had no issues. Less than 12 months later it went so had to do the coolant again, so if you've got a pump waiting to go on (stat too) you might as well do it at the same time.

I did a coolant flush after doing the gaskets, and I think a run and drain with plain water too to clean out the flush. Easy with the elec pump.
 
Not the exact same engine but close enough. Many small fragile pipes, miss the middle section fast forward to 11 minutes. https://www.youtube.com/watch?v=I95LurFYbtg&t=775s
 
j24 said:
Chippie said:
While you are in there it may be prudent to do the belts, I did preventative maintenance on my N54’s water pump, the new one lasted less than a thousand miles so I’d probably leave the alternator, but others may suggest different.

Yikes - I've also got an OE Pierburg water pump waiting to be installed as preventative maintenance! It only lasted 1000 miles?? That's a bummer. What brand did you go for?

Anyway thanks for the thoughts! Think I'll do both gaskets and the serpentine belt as a minimum.

It was a Pierburg pump, I think I was just unlucky.
 
enuff_zed said:
I think I'd stop at belts too.
While you're in there though, take a good look at the alternator. See how the diode/brush pack attaches to the rear of it.
More often than not this is what fails and it can be changed in situ (well it can on an M54).
Handy to know for future reference.

Thanks Martin. I found a pic on elsewhere on the forum, and looks like the alternator is a little packed in so might be a bit difficult to assess/change in situ on an N52:

file.jpg

Like the idea of possibly swapping in a new diode brush pack whilst I'm in there as a bit of preventive maintenance. But I'm having a bit of a nightmare trying to figure out what the part the diode/brush pack is - I'm getting a few different looking results for alternator voltage regulators on https://www.motor-doctor.co.uk/alternator-regulator/bmw/z4/z4-coupe-e86/19300-3-0-si

Was hoping that I'd be seeing variations of the same part, but there are a few different ones on there!
 
Scooba_Steve said:
It's a bit of a ballache taking stuff off, so while you're there might as well do the belts, tensioner and any pulleys. They're cheap.
I also changed the alternator while it was off, for the same reason.
Cheers Steve - still mulling over how far I go with it, but I ended up ordering a new INA tensioner and pulley, alongside a Contitech belt. Think these are all OE/genuine parts, and were a decent price on Autodoc yesterday, so figured I'd order them in and continue to think things over...

Also very aware that I'm pushing my spannering abilities, so it's all feeling like a bit of a dive in the deep end at the moment.

Feeling largely okay about the oil cooler/filter housing gaskets - although I'm worried at the lack of space, particularly with some of the more fiddly parts of the job which are difficult to reach/manoeuvre. So it might be a 'see how I go'.

I've heard that the serpentine belt is easy to remove/fit, but no idea how I'm going to simultaneously get my hands in the space and see where I'm meant to position it at the moment!!
 
By the time you've tried every last combination of belt and pulley sequence, because you've forgotten what it was like when it came off, you'll be able to do the job in the dark.

I've found.
 
j24 said:
Like the idea of possibly swapping in a new diode brush pack whilst I'm in there as a bit of preventive maintenance. But I'm having a bit of a nightmare trying to figure out what the part the diode/brush pack is - I'm getting a few different looking results for alternator voltage regulators on https://www.motor-doctor.co.uk/alternator-regulator/bmw/z4/z4-coupe-e86/19300-3-0-si

Was hoping that I'd be seeing variations of the same part, but there are a few different ones on there!

Well depending how long you are taking to do the rest of the job, you could actually remove the alternator, take off the pack to see what condition it is in and then you should be able to get a number off it to buy a replacement.

How much is an alternator though? Other option is to swap in a new one and keep yours as a known working spare.
 
smorris_12 said:
By the time you've tried every last combination of belt and pulley sequence, because you've forgotten what it was like when it came off, you'll be able to do the job in the dark.

I've found.

Ha, yep, there's that!!

Looking into the engine bay right now I can hardly see the belt/pulleys, but I'm sure I'll be able to figure it out when I've taken the OFH etc off... famous last words!

enuff_zed said:
Well depending how long you are taking to do the rest of the job, you could actually remove the alternator, take off the pack to see what condition it is in and then you should be able to get a number off it to buy a replacement.

How much is an alternator though? Other option is to swap in a new one and keep yours as a known working spare.

Yeah, that's a good point... looks like I can get a new Bosch alternator (assuming it's the OE part?) for around the £190 mark:

https://www.partsinmotion.co.uk/car-parts/oem/12317543083 (there's a 10% off code I can use as a new subscriber)

Autodoc has it listed £160 right now, but to actually get that price you need to pay a 'core charge' of £125 on top of that (so £285), then have to send the old alternator back to them at my expense, which sounds like a bit of a faff and would probably work out similar price wise to the above.

From a quick google around, I think £190 seems like a reasonable price?

It's just another large-ish expense for me to weigh up, and a question of saying sod it and going for it, or hoping the current one keeps working for a while longer... Expense today vs expense + additional faff tomorrow (without knowing exactly when 'tomorrow' is!)

Slight tangent, but just checked my battery whilst I'm thinking about the alternator... looks like my OE BMW battery is dated 12/2015, so wondering if I'll need to swap that out soon too, assuming the original battery lasted 7 years.

I might as well go ahead and start the inevitable rebuild thread :rofl:
 
j24 said:
Looking into the engine bay right now I can hardly see the belt/pulleys, but I'm sure I'll be able to figure it out when I've taken the OFH etc off... famous last words!

May sound odd, but I find it much easier to put the car up on ramps at the front, then get the engine tray off and do the belts from underneath.
Take a photo before you start, or a sketch of the routing.

I must say that I also find it much less strain on my back doing engine jobs with the front of the car raised.
 
Out of interest, are N52 alternators a weakpoint? Between my M47 and M57 the alternators have happily done nearly half a million miles. Conversely, various old TD5 Discos of my acquaintance with Valeo alternators used to get thru brushes for a pastime.
 
j24 said:
I've heard that the serpentine belt is easy to remove/fit, but no idea how I'm going to simultaneously get my hands in the space and see where I'm meant to position it at the moment!!
I remember needing quite a large torx and breaker bar to take the tension off. Unless you want to cut the belt.
j24 said:
Also very aware that I'm pushing my spannering abilities, so it's all feeling like a bit of a dive in the deep end at the moment.
It's not difficult, just fiddly. I am sure there is a good guide on here, or maybe the other forums that include 3er.
 
I did the belt (only 1 on N52) tensioner and alternator clutch pulley, I read that this fails before the alternator. Easy to do from above when you remove the fan. Do your research and make sure you have what you need before you start. I had no experience at all, youtube was my guide.
 
Found the guide I used for the belt and tensioner, this guided me through the job, I did the alternator clutch later as I needed to order a tool. It was very straight forward.
https://youtu.be/QdqfR-yKlyg
 
smorris_12 said:
Out of interest, are N52 alternators a weakpoint?

Good question... I was thinking along the lines of it might need replacing sometime soon due to age/mileage, so might be worth sorting whilst I'm there already. Still 50/50 on it...

Scooba_Steve said:
I remember needing quite a large torx and breaker bar to take the tension off. Unless you want to cut the belt.

Cheers - yeah a T60 torx from what I've seen - I've got a torx set and breaker on the way from Amazon.

Dark Diggler said:
Found the guide I used for the belt and tensioner, this guided me through the job, I did the alternator clutch later as I needed to order a tool. It was very straight forward.
https://youtu.be/QdqfR-yKlyg

Ah, brilliant - thanks!
 
So I've just noticed that on RealOEM, the belt size is listed as 6PK 1827 - but the belt I've ordered from AutoDoc (and from I can see, every other aftermarket belt) seems to be 6PK 1830...

What's that about? I can't find any belt other than the official BMW part that's the exact same size... is that a problem?


Screenshot-2023-03-15-at-16-20-18.png



Screenshot-2023-03-15-at-16-22-53.png
 
3mm isn't going to make any odds. BMW can spec "perfect" belts for manufacturing while the aftermarket will cater to many markets so will lump ranges of sizes together.
 
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