Unfortunately, due to my special ability to keep bringing neglected cars home with me, I now have a dire need to make some space, so the BMW will be sold.
But of course, being me, I can’t sell the car without first making it better than when I got it.
That meant I needed to look into why the car kept marking its territory everywhere it was parked.
The previous owner mentioned it had an oil leak when he sold it, but “didn’t know” where it was from. A quick look around under the bonnet at the common failure points identified two sources of the leak; the rocker cover gasket and the oil filter housing.
I identified these quite early in my ownership, and ordered the relevant parts to fix it. It’s taken me until now to actually do it though (and typically, only really for sale).
The first step is to pop the bonnet and glare at the engine that didn’t magically fix itself.
The leak from the oil filter housing is both a very common issue, and quite easy to see. Just grab a torch and have a look around the housing and look for pools of oil and lots of muck
The other source was the rocker cover, which was leaking on the low side of the gasket. It’s harder to see, but look for wet black muck along the side and front corner of the engine
I started with the oil filter housing. To access this, first, the airbox and all associated gubbins need to come out. The top comes off nice and easy once you undo the hose clamp to the AFM, disconnect the air temp sensor and AFM and unhook the clips around the edges. Remove the lid and filter.
In both the top of the lid, and the bottom of the box it was lined with some noise-dampening foam. This was all starting to crumble if you so much as looked at it. Its held in place with a plastic cage that is clipped into the bottom of the box.
Then I just scooped the foam out of the bottom. The rest got tipped into the bin once the bottom of the airbox was removed.
Which is done by undoing the two bolts on the inner guard, and then normally it would just lift out, except for the giant stupid air duct that runs over the radiator. That needs to come out first, by undoing the four bolts on the top housing and removing the housing. The lower half of the housing is clipped into the fan shroud.
So much room for activities. It’s crazy how much engine bay there is in front of the engine on the 4 pot BMWs. How much space? You can fit a jandal between the radiator and engine.
The next job to do, is disconnect the battery as we will be messing with the feed to the alternator
It’s best to crack the oil filter housing cap off now, whilst it’s attached to the car. Mine was done to eleventy-thousand NM and needed a breaker bar to crack it. The force started to round the brand new filter housing tool. It only needs to be 25NM, and heck it’s moulded into the cap if you forget!
I like to completely open the cap, as this can let the extra oil in the filter housing drain back to the sump.
Now I had to remove the drive belt. This is done by backing the tensioner off. Remove the plastic dust cap to expose the 16mm hex bolt in the center
Use a rachet or bar and turn counterclockwise to loosen the belt, and slip it off the alternator pulley
It pays to take a couple of photos of how the belt runs too. It’s pretty simple, but could be easy to route incorrectly.
With the belt off, it was time to work on removing the alternator
Undo the two wiring connections on the back first. One is 10mm, the other 13mm.
Now the two alternator bolts need to be removed. The top one will come out easy enough
But the bottom one will hit the power steering reservoir
So the trick is to undo the two nuts that hold the res on, wiggle it off the studs and gently move it out of the way
Now use lots of wiggling and a pry bar to remove the alternator. Take care because it is quite heavy.
Now we have access to the bracket, but still not the housing. Remove all four bolts.
Once you remove those bolts, you can pivot the bracket away from the engine on the lower power steering pump bolt. This gives you access to the oil filter housing.
Yup, I think it’s been leaking
Gently crack off all the bolts and remove them. That bottom corner one will envoke some great curse words, since it’s got very limited space to work with.
Once the bolts are out, the housing should need some wiggling to free, since the top bushing should be sealing to the block, but in my case, it almost fell out.
The bushing was stuck in the housing
The bushing has a pair of o-rings on it. The old ones were flat and hard as plastic. The new o-rings are visibly larger.
Everything got a real thorough clean down, to make sure the gasket surfaces were spotless. I then lubricated the bushing with some oil and pressed it into place in the block. A very thin smear of Hylomar was wiped on the block side of the gasket surface, and the gasket stuck to it. The housing was then refitted, the bolts all done hand tight and a new oil filter fitted. The braket, alternator and belt were refitted.
That’s half the job done. Next was the rocker cover gasket.
The spark plug cover comes off first, using a screwdriver to turn the two locks
Hey, what’s that blue thing?
It’s a built-in spark plug boot puller. Slip it over the top of the boot, pop a screwdriver through a hole and use it to pull the boot out
That’s a really cool touch. What wasn’t cool, was finding cylinder two was drowning in oil
I completely removed all leads and coil pack together
All the cover bolts were loosened. If they have been there a while the rubber seal will stick them to the cover, otherwise they will come right out. Once again, the back corner ones will make you hate BMWs. Don’t forget to carefully remove the PCV hose from the back of the cover (although chances are this has turned to chewing gum and will break).
With some careful prying in various places, the cover will pop up and can be removed.
Something tells me it’s been leaking a bit
The gasket was pretty moist
I didn’t think the gasket was too bad; it still felt flexible like rubber, but once I removed it, it held its shape and was stiff as a board. The new gasket is all floppy.
The new gasket kit came with seals for the bolts too. Not all kits come with these, I specifically chose one that did.
The old seals were quite hard and had been compressed. Since the bolts bottom out, if the seals are too compressed, they won’t seal.
I used some side cutters to snip the seal and then ripped it off
Then using an appropriately sized socket, some silicone grease and a soft face hammer, I knocked the new seal on, using the socket as a driver and a couple of good whacks from the hammer to get it over the shoulder.
A stack of old bolts with new seals
Now it’s time to bugger around getting the new gasket into place. I tried a few different ways to do this, and they all sucked. The one that worked was to fit the gasket to the cover, zip tie it into place (with an additional zip tie where the arrow is), and try to keep the gasket from snagging too badly as you refit the cover.
Don’t forget to bad some sealant on the corners of the half moons at the back
And on the timing cover joints
With the cover in place, as long as the half moons are correctly seated, insert a few bolts finger tight and then snip and remove the zipties. Insert all the bolts, and torque to 10nm working from the inside out.
Now is a good time to grab a mirror and check out the back of the engine and make sure the half moon sections of the seal are correctly located and seated. The mirror can also help to check the rest of the gasket.
Before refitting the rest of the parts, I changed the spark plugs. The old plugs were genuine BMW, and quite worn (even for the weird 4 electrode plugs). I wouldn’t be surprised to find they were original.
In went a new set of BKR6EK (twin electrode) and the leads and coil were then refitted.
Next was to change the PCV valve. I had heard these can cause the unstable idle if they are tired, so I thought I’d give it a go.
This is a real fiddle to do. First, remove the battery. Next use a T30 on a 1/4″ ratchet to undo the two bolts, trying not to drop them.
You can unhook the hose from the PCV if it’s in good shape, or in my case, I just cut the hose to remove the PCV.
You can see how dirty it was around the valve. The gasket was very flat and the internal components were covered in filth
The old hose was soft like chewing gum and had crumbled internally
I replaced that hose with some oil/fuel safe 5/8″ hose. I did need to cut the plastic sleeve that joins the PCV hose to the coolant hose. I carefully did this with a sharp knife.
Finally, I ripped all the foam out of the airbox top
And drained the old oil and filled it with 5.5L of nice fresh 10W50 Penrite. The old oil wasn’t due to change for another 4000km, but was overdue by time. It was black and stank like old oil. The previous owner had been topping it up too, so who knows what it was.
Starting the engine up, it still started and ran the same, so the PCV hasn’t magically fixed the idle. I suspect it requires the typical M44B19 timing adjustment, but I’m not going to mess with that. The idle is a bit lumpy, but harmless.
I backed the car up the drive and gave it all a real good degrease and wash down. There was old oil everywhere, and it’s still not perfectly clean, but it’s better. It was ridiculous how much fresh oil there was on the underside of the engine/steering/gearbox/everything. It had leaked about a litre of oil in the short time I had been driving it, so it was getting through it.
A quick run around the block to dry the engine off, and into the garage it has gone. It needs a clean inside and out, and then it’ll be ready for sale. The engine got a quick wipe down, which helped, but I can’t do much about the old yellow cosmoline wax all over the engine, that’s just an old BMW thing.
Hopefully it won’t take long to sell. It’s a good little car and I have enjoyed my time with it, but I’d enjoy the space and cash more.