Looking after old BMWs
23 Aug 2025 · Maintenance · Servicing
Maintenance
I love old BMWs. E46s & E60s are I think peak BMW. The trouble with liking old cars is that to keep them running and safe they require much more thorough maintenance than new cars. Luckily I'm a dab hand with a spanner and for jobs that require more than basic spanner control, my brother is a time served mechanic, with access to a workshop with lifts, pits and all manner of specialist tools!
There's nothing about maintaining an old BMW that isn't pretty much the same as maintaining any other older car.
Engine, Transmission, Brakes, Suspension, Electrics and bits n bobs. That's all any car is made up from.
Everything gets logged on a spreadsheet so I know what I've done, when I did it, where I got the bits from and when it needs doing again. I've got a sheet for each car I've had, going back through my last 8 cars (not all old BMWs).
Engine Oil Change
First & probably most important maintenance for high mileage heroes is oil changes.It's a nice easy job, you empty out the old oil, change the filter, change the drain plug crush washer & refil the oil. I like to throw a can of engine flush in with the old oil befor I drain it.
Get the engine up to temperature & pour in the oil flush, leave it running (not driving) for 5-10 mins. Switch the engine off and remove the filler cap. Get your old oil catch container ready (my car takes close to 7l), line it up with the drain hole and remove the drain plug.
Clean the oil filter housing, replace the O rings, run a little clean oil over the rings and replace the filter. Hand tighten the oil filter. With the car as level as you can get it fill up the oil.
When it idles it'll pump the oil round all the now empty voids and the filter will take some up. Turn it off and then check the level again. Then fill it back up to the middle of the fill to here marks. Leave it off for another 5 minutes and then check it again. If it's still at the middle you're done.
5w30 is recommended by BMW, so that's what I use. There's a bunch of other technical specifications about other technical bits and bobs. I generally put my reg number into autodoc and get 2 x 5l bottles of whatever it recommends. It takes about 6l depending on what you can extract. The book says it takes 6.75l but I've never been able to get that much out! I decant 1l into a small bottle that I keep in my boot 'just in case'. If I need to top it up then I use the bottle and refil it so I can keep track of how much it's using (not a lot).
Transmission Oil Changes
Some manufacturers tell you this is a lifetime oil. Oil is cheap (2l of Liqui Moly 75w80 transmission oil was £34 when I last bought it), gearboxes are not. Change the oil. Same high level process as oil changes, with slightly different fill technique. Drain the old oil, refil it with new oil. Job's a good un.Remove the fill plug. This is to make sure that you can get it out to refil it before you drop the old oil. Old oil is better than no oil. If you can't get the fill plug out, and you've drained the oil, you're knackered. Once you've got the fill plug out, line your oil oil catcher up with the drain hole and remove the drain plug. Leave it to empty out, don't rush this step, get as much out as you can. When it's done draining, clean the drain and fill plugs, replace the crush washers & replace the drain plug.
You need a pump to get the oil back in, some bottles come with a pipe, but they're very rarely long enough and they're always a pain. Buy a cheap oil pump when you buy the new oil. BMW recommends, 75w80, so that's what I buy. Refil the oil slowly. Mine has a capacity of 1.6l, but I've never been able to get 1.6l out.
Differential Oil Changes
The differential allows the wheels to turn at different speeds. When you're driving round a corner the wheel on the inside of the corner needs to turn slower than the wheel on the outside of the corner, that's what the differential does. They're pumpkin shaped boxes full of gears.Again, some manufacturers say it's a lifetime oil. Ignore them, change it. (2l of Liqui Moly 75w90 differential oil was £42 when I last bought it)
Exactly the same steps as gearbox oil. You need a pump. Remove the fill plug before you remove the drain plug. Drain the old oil, replace the crush washers, slowly refil the oil until it flows out of the fill hole, replace the fill plug. Clean up, you're done.
Brakes
The brakes are one of, if not the primary safety systems on your car. With that in mind if you don't know what you're doing you should probably get someone who does to help you with this job. Once you've been instructed you'll be able to do it yourself. There's two main elements to the brake, the disc and the pad. The disc spins with the wheel and the pad is fixed. When you press the pedal the caliper squeezes the pads onto the disc and it converts the rotatational energy into heat and the car slows down.
You should change the pads when they get to the minimum thickness. You should change the discs when they get to the minimum thickness or they develop a lip.
When you're changing the pads, make sure to give the calipers a brush over with a wire brush, make sure the sliding surfaces are nice and smooth.
Brake fluid doesn't last for ever. You should change it every so often. It's another one of those that I'm not going to explain how to do. If you don't know how to do it, get someone who does to show you the steps.
In essence, drain the old fluid, replace it with nice new fluid. When you've done this you'll need to bleed the brakes. Bleeding brakes removes any air in the lines. Air compresses, brake fluid doesn't. If you've got air in the lines then your brakes will feel squishy and won't work well. Bleeding brakes is either a two man job or you need a brake bleeder.