Servicing of very low usage 635s

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plip1953
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Servicing of very low usage 635s

Post by plip1953 »

I have a feeling that the last time I changed the engine oil on my car could be as long a long a 20 years!! And at the time I do recall it was with the then very much in fashion Mobil 1, although have no idea what viscosity.

Since then the car has probable covered no more that 3000 miles, but needed nothing doing to it engine-wise.

I feel I really should now change the oil (better late than never!!), but would appreciate any thoughts on what might/will have happened to the oil that's currently still in the engine (ie to what extent and in what way might it have deteriorated?), and also what might be the best replacement in terms of viscosity. Should I even consider doing a double change in relatively short order?

On the auto gearbox front, I'd say there's every chance the oil has never ever been changed! I did ask my local garage to do it around 10 years ago, but they were concerned that at least some of the sump bolts might break when being loosened. How critical is it that the gearbox oil (and filter?) is changed? Functionality of the box seems just fine.

For various reasons, the rear diff, power steering, coolant and brakes have had fluid changes more recently.
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Re: Servicing of very low usage 635s

Post by 635sharknose »

To my knowledge the oil might be contaminated by water, coolant, dirt, fuel, etc..
Broke down oil can cause sludge or bad lubrication.
As changing the oil (and filter) isn’t too expensive, I would do it if I where you.

Gearbox oil would hold much longer as it is not contaminated by combustion.

I use this oil:
https://www.kroon-oil.com/en/product-re ... ent:13870/
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Re: Servicing of very low usage 635s

Post by bpoliakoff »

I personally would do a double oil change. Run some less ex[pensive oil trough with a new filter at temperature as a flush and then refill with a good quality oil and another new filter
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Re: Servicing of very low usage 635s

Post by plip1953 »

Thanks for the replies.

The recommended OE engine oil viscosity appears to be 10W 40. That seems to be a pretty safe bet to me given that the car won't be used in winter, and nor will it be driven hard enough to produce really high operating temps.

When I drop the old oil I'll certainly be giving it a good look for any obvious contaminantion etc
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Re: Servicing of very low usage 635s

Post by olympia57 »

If you haven't changed the oil in twenty years Phil I suppose we should remind you to change the filter when you're at it .......

Do the auto box when you are under there . Drain and change the oil, filter and sump seal / gasket , it's cheap and easy to do and silly to leave for 32 years .
The sump on the 4HP22 is similar to my 3HP22 and is retained by four bolts and saddles . There are several common sense approaches to reducing the possibility of shearing these bolts , I'd be optimistic about removing them without damage .
http://bmwfans.info/parts-catalog/E24/E ... s_oil_pan/
Going forward I'd strongly suggest that you change the oil and filter each year irrespective of use and , or lack of , miles .
15 /40 mineral besed oil and a filter will cost you less than £20 and if you don't believe me just compare the full spec.( not the viscosity ) of Lidl's 15 /40 mineral with the Castrol , Shell and Mobil's of the world , you'll be pleasantly surprised .
Buy the oil not the brand .
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Re: Servicing of very low usage 635s

Post by wattsmonkey »

What's the current thinking on ZDDP content of newer - cat friendly - oils?

I tied myself in knots about this before settling on Mobil 1 Extended Life 10w/60 for the M88 for the above reason. Not the viscosity I would have chosen - I'm with Don on 15W/40 as the ideal for our climate here in the UK, especially for the M30 - but the 1300ppm of zinc sold it to me. Also, the M really did seem to like it.

Just a word of warning - doing searches on the best oil for the M30 or M88 is a rabbit hole from which it is hard to emerge without a either a headache or a pressing need for the divine wisdom of Brucey!
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Re: Servicing of very low usage 635s

Post by plip1953 »

olympia57 wrote: Tue Apr 28, 2020 9:39 pm If you haven't changed the oil in twenty years Phil I suppose we should remind you to change the filter when you're at it .......

Do the auto box when you are under there . Drain and change the oil, filter and sump seal / gasket , it's cheap and easy to do and silly to leave for 32 years .
The sump on the 4HP22 is similar to my 3HP22 and is retained by four bolts and saddles . There are several common sense approaches to reducing the possibility of shearing these bolts , I'd be optimistic about removing them without damage .
http://bmwfans.info/parts-catalog/E24/E ... s_oil_pan/
Going forward I'd strongly suggest that you change the oil and filter each year irrespective of use and , or lack of , miles .
15 /40 mineral besed oil and a filter will cost you less than £20 and if you don't believe me just compare the full spec.( not the viscosity ) of Lidl's 15 /40 mineral with the Castrol , Shell and Mobil's of the world , you'll be pleasantly surprised .
Buy the oil not the brand .
I fully agree that an interval of 32 years is massively excessive, verging on irresponsible!!

Is there a particular ATP that should be used?

Are you actually advocating mineral oil for the engine?
Phil
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Re: Servicing of very low usage 635s

Post by plip1953 »

wattsmonkey wrote: Wed Apr 29, 2020 7:20 am What's the current thinking on ZDDP content of newer - cat friendly - oils?

I tied myself in knots about this before settling on Mobil 1 Extended Life 10w/60 for the M88 for the above reason. Not the viscosity I would have chosen - I'm with Don on 15W/40 as the ideal for our climate here in the UK, especially for the M30 - but the 1300ppm of zinc sold it to me. Also, the M really did seem to like it.

Just a word of warning - doing searches on the best oil for the M30 or M88 is a rabbit hole from which it is hard to emerge without a either a headache or a pressing need for the divine wisdom of Brucey!
Is it only the Mobil 10w 60 that has the high zinc content? I'd rather use a 15w 40 or maybe a 15w 50, but am readily willing to accept the particular characteristics of specific oils (ie the additives) is probably more important than viscosity (within reason).

I'm pretty sure the oil in the engine right now is Mobil 1 (but don't recall the viscosity), but it would have been from back in the days when it was relatively new and "in vogue". Is there anything in that particular oil that might indicate what to use next?

As a matter of interest, what kind of oil temp is considered "normal" for a healthy M30 engine?

I think I might give Opie Oils a call and see what they have to say.
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Re: Servicing of very low usage 635s

Post by olympia57 »

plip1953 wrote: Thu Apr 30, 2020 10:43 am
olympia57 wrote: Tue Apr 28, 2020 9:39 pm If you haven't changed the oil in twenty years Phil I suppose we should remind you to change the filter when you're at it .......

Do the auto box when you are under there . Drain and change the oil, filter and sump seal / gasket , it's cheap and easy to do and silly to leave for 32 years .
The sump on the 4HP22 is similar to my 3HP22 and is retained by four bolts and saddles . There are several common sense approaches to reducing the possibility of shearing these bolts , I'd be optimistic about removing them without damage .
http://bmwfans.info/parts-catalog/E24/E ... s_oil_pan/
Going forward I'd strongly suggest that you change the oil and filter each year irrespective of use and , or lack of , miles .
15 /40 mineral besed oil and a filter will cost you less than £20 and if you don't believe me just compare the full spec.( not the viscosity ) of Lidl's 15 /40 mineral with the Castrol , Shell and Mobil's of the world , you'll be pleasantly surprised .
Buy the oil not the brand .
I fully agree that an interval of 32 years is massively excessive, verging on irresponsible!!

Is there a particular ATP that should be used?

Are you actually advocating mineral oil for the engine?
If you use your car on average 150 miles per annum , in summer and in your own words " and nor will it be driven hard enough to produce really high operating temps." then any good quality 10 or 15 /40 ACEA A3/B3 or B4 multi grade oil will happily do the job. Mineral based or semi synthetic . I find fully synthetic too thin for older engines but I'm sure others will differ .
As above ,any good quality ATF will do the job.Check your owners manual for recommendations.
As wattsmonkey says , don't open the Pandoras box of "best oil for ..........."
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Re: Servicing of very low usage 635s

Post by plip1953 »

My dilatory behaviour turns out to be slightly less bad than I thought!

I now recall that at the time the gearbox sump pan didn't come off (with a view to changing both the oil and filter) my garage did at least change to oil. So in practice the current gearbox fluid will only have been in the car for a few thousand miles at most.

And maybe a bit better news on the engine oil front because I now see I have a main dealer stamp in the service booklet from 2008. So only 12 years since that oil hasn't been changed lol

Another thing that has never been done is adjustment of the valve clearances. Is that common on the M30 engine ie insofar as it's rarely needed? The engine purrs very sweetly, and the only tap tap noise is from the injectors, but of course that's entirely normal. Total engine mileage is 73k.
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Re: Servicing of very low usage 635s

Post by olympia57 »

Fresh Oil will do Phil .
I'd still change it twice . First time run it up to temp , with a new filter fitted , and then drain it and change the filter again and replace with fresh oil .
Depending on what oil you choose you could use a cheaper ,but still rated 15/40, for the first run through .
Valve clearence will be fine if , as you say , you cannot hear them .
Personally I'd still change the gearbox filter and ATF too . I did on my 3HP22 and was surprised at the level of fine metal in the filter . My car has only done 71K miles with full service history . As I said , the filter is straight forward to do and inexpensive to buy.
Anyway , you'll be full speed ahead now with a warm glow of satisfaction getting it all done and stamped up to date .
Good luck.
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Re: Servicing of very low usage 635s

Post by plip1953 »

For completeness......today, I finally got round to changing the oil and filter. To be fair the old stuff looked pretty reasonable, but a change was probably due anyway.

I also changed plugs, distributor cap and rotor arm.

Started her up and sounding nice and sweet - just like it has always done. I also tried a hot restart and that wasn't a problem, so hopefuly that issue of recent times has now gone away too.
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Re: Servicing of very low usage 635s

Post by olympia57 »

A job well done ....

Now don't be leaving it for another 20 years :D
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Re: Servicing of very low usage 635s

Post by 635sharknose »

Good job Phil, let's make some miles with it! :D
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Re: Servicing of very low usage 635s

Post by plip1953 »

You're both right of course, but I'm not so sure it'll happen anytime soon.

Just one issue I've encountered with the oil change - the filter housing is reluctant to seal properly. I used a new O ring, but it leaked from the get go. So I've now reverted to the old seal, but still it's weeping. It was never a problem before.

Any thoughts?
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Re: Servicing of very low usage 635s

Post by plip1953 »

Something else the cropped up for the first time today was a hint of hunting during warm up at idle. And the idle speed seemed a little low.

Is there a set procedure for trying to optimise base idle mechanically ie with the throttle butterfly setting, and then ensuring the throttle position sensor is adjusted, if required, to ensure it knows the engine is at idle.
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Re: Servicing of very low usage 635s

Post by emac »

If you didnt change any fluids, how did you keep the fuel from going bad? I have several cars in storage and my biggest concern is fuel stability. I use non ethanol fuel/stabil and keep a note in the car when it was filled up. The years go by fast!

I keep a small notebook in the car and write down the dates of fluid changes. Brake and coolant every 2-3 years, I think is very important.
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Re: Servicing of very low usage 635s

Post by plip1953 »

emac wrote: Tue Jun 02, 2020 1:52 am If you didnt change any fluids, how did you keep the fuel from going bad? I have several cars in storage and my biggest concern is fuel stability. I use non ethanol fuel/stabil and keep a note in the car when it was filled up. The years go by fast!

I keep a small notebook in the car and write down the dates of fluid changes. Brake and coolant every 2-3 years, I think is very important.
All I can say on the fuel front is that I've not knowingly encountered any issues from fuel that may have been in the tank for a number of years. I used to think that it was a good idea to keep the level in the tank quite high, thinking that it would help protect the tank itself from internal corrosion, but have more recently kept it fairly low during storage so that when I do start using the car again I can add a high proportion of fresh fuel. Nevertheless, first start ups, even after a long period of storage, have always been using whatever fuel was in the tank and it's started first time and run just fine every single time.

I don't think coolant changes need to be performed anything like as often as every 2 years. But testing it annually to ensure it still has the ability to deal with sub zero temps would probably be a good thing. Changing brake fluid every couple of years or so is probably the prudent thing to do, but I prefer to do it on the basis of it's degree of water absorption rather than simply on a time basis.
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Re: Servicing of very low usage 635s

Post by 86_6series »

plip1953,

How do you measure "degree of water absorption"?
I'd like to use this method.

I think it's better to have a full tank, you won't get much condensation buildup
to rust the tank.
Last edited by 86_6series on Tue Jun 02, 2020 2:29 pm, edited 1 time in total.
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Re: Servicing of very low usage 635s

Post by emac »

I think tank corrosion and water absorption may depend on your local environment, so what works for one person, may not for others. It gets pretty humid in my neck of the woods. Coolant isnt just about freeze protection, it also has corrosion inhibitors that dont last forever. Who knows what the right answer is......BMW used to suggest coolant changes every 2 years, now it is a lifetime fill!
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Re: Servicing of very low usage 635s

Post by plip1953 »

86_6series wrote: Tue Jun 02, 2020 11:58 am plip1953,

How do you measure "degree of water absorption"?
I'd like to use this method.

I think it's better to have a full tank, you won't get much condensation buildup
to rust the tank.
My local garage has some kind of device, but I'm afraid I don't have details of it.

But this seems to suggest at least a couple of options.

https://carhampt.com/best-brake-fluid-t ... luid-life/
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Re: Servicing of very low usage 635s

Post by 86_6series »

Thanks for the heads up. I'm ordering mine today.'
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