Progress on the BMW Z3

After purchasing my Z3 1.9 back in October 2019 and having all the mechanical items sorted it was time to put the Z3 to bed for the winter as the weather was not up for me working on the car. 

The winter was spent Googling, watching YouTube, talking on Z3 forums and basically working out how I was going to tackle the items that I had found needing attention on the car. As with any car of its age, the list of jobs to tackle was not a small one.  

The main items needing attention were to replace the sills, fix the central locking and interior light not working, body work and refurbish the leather seats.  

Sills were purchased from Sytners Sheffield, painted by a local body shop and fitted one weekend. The frame under the sills looked to be in good condition with some surface rust. The frame and back of sills were treated with wax oyl before the sills were fitted. 

 The issue with the central locking turned out to be a familiar issue with the Z3, a broken cable in the loom going from the boot. A bit of soldering later and the central locking works as expected. The interior light not coming on when the doors were opened turned out to be a simple fix too, the connection of the wire on to the light switch just needing a clean. 

After a trip in February to the Leather Repair Company in Hull with the Eastern region we felt we had all the knowledge, and a repair kit, to refurb the leather seats. The transformation is astounding and well worth the effort. We re-dyed the leather whilst the seats were out of the car since the bushes on the seats needed to be changed to stop the seat moving back and forth. Changing the seat bushes turned out to be a much easier job than I thought it was going to be, just having to remember to count the number of turns for the runner.   

Whilst the seats were out of the car, I took the opportunity to put my hand under the carpet. When I first got the car there were no rubbers on the hood that go above the door and the inside was soaked. The foam under the carpet on the passenger side was soaked in water and squeezing the foam caused a torrent of water to release. I pulled the carpets up as much as possible squeezed out as much water as possible and left to dry out. It took three days. 

The body work required some attention on the front bumper and both rear arches. A couple of small rust spots on the arches turned out to go a bit further once sanding commenced. After some sanding, filling, sanding, primer, base and lacquer the car looks great. The body work still needs some attention and a good machine polish at some point. One thing I learnt from spraying the bodywork is that more base colour and lacquer is required. You’ll never get the same quality finish from a spray can as you would from the body shop but it looks presentable now at least. 

Checking the oil level for the Z3 1.9

  1. Drive the car to bring it up to temperature
  2. Park the car on a flat surface
  3. Leave the car to cool for 5 minutes
  4. Pull out the dipstick and clean it with a lint free rag or paper tissue
  5. Put the dipstick back in to the engine making sure it is pushed in fully
  6. Pull out the dipstick and check the level
  7. The level should be between the lower (min) and upper (max) marks.
  8. Add oil as required
  • The difference between the lower and upper marks on the dipstick is approximately 1 litre of oil.
  • Do not fill above the upper mark as too much oil can hurt the engine.
  • Do not add oil until the level is just above the lower (min) level
  • Oil for the Z3 1.9 petrol engine is 5W30.

Re-Attach Rear View Mirror

My rear view mirror dropped off during the winter. I have tried various products to fix it back but none worked that well. Eventually I tried the Loctite 319. This stuff is awesome.

  • Remove the button from the mirror so that you are only glueing the small part and not the weight of the whole mirror. 
  • Take the mesh that comes with the Loctite and cut it to the required size of the button.
  • Clean the window with some cleaning alcohol to remove any grease, etc
  • Clean the button with some cleaning alcohol to remove any grease, etc
  • Put the glue on the button
  • Place the cut down piece of mesh on to the glue and use the glue stick to make sure the mesh is covered
  • Place the button on to the window (making sure you have it properly oriented with a notch to the top) and hold the button in place and count slowly to 30. 

The button should at this point be fairly secure. I then left it to set for about an hour. I then reattached the mirror to the button. Feels really firm and secure.
I should also note that I waited until it was a warm sunny day so that there was no condensation or moisture on the windscreen and the windscreen was warm. This helps the glue work to its full effect. 

Z3 Central locking not operating boot from doors

My Z3 has a strange central locking issue that I need to look in to. When I use the key in either the passenger or drivers door it will operate the central locking for the doors. The boot does not lock or unlock if the key is used from the doors. If I use the key in the boot lid to unlock / lock the boot it also operates the doors. So, if I use the key in the door to unlock the door, both doors unlock but not the boot. If I lock the door from the door, both doors lock but not the boot. If I unlock the boot using the key in the boot, the boot will unlock and both doors will unlock. If I lock the boot from the boot lock, the boot will lock and both doors will lock. So, if I unlock the car from the boot and then lock the car from the doors, the boot will not be locked.

It appears that the signal from the central locking from the doors is not making it to the boot actuator. There is a known issue on the Z3 where the wiring loom that goes from the boot in to the car can sometimes contain broken cables. It could be that there is a broken cable in the loom. You can see examples of broken wires in the photos below (courtesy of @jonco on Detailed below are the indvidual wires and there function.

As soon as lock down allows I will be out to the car to break open the wiring loom to see if any of my wires are broken and causing my issue. I will update the post with what I find.

I have documented here the details of what each wire is used for is noted below (courtesy of @jonco and @BrianH on

There are 9 wires in the boot loom. The lock/unlock and switch position functions are controlled via the central ZKE module
The two wires below are part of a common loom that triggers the door actuator/lock.

1.5 BL/GR blue/grey – boot lock motor wire

1.5 WS white – boot lock motor wire

The three wires below are supply wires and lock position wires, the supply is fed from fuse 7 (5amp)

0.35 RT/GN red/green – boot lock switch – supply wire

0.5 WS/BL white/blue – boot lock switch – unlock wire

0.5 WS/GN/GE white/green/yellow – boot lock switch – lock wire

The two wires below are for the third brake light, the fuse for the third brake light is fuse F46 (15A) and controlled via the brake light switch.

0.5 BR brown – 3rd brake light – earth

0.75 BL/RT blue/red – 3rd brake light – supply Wire

The two wires below are for the boot interior light, this switch is located in the boot latch. The fuse for the boot light switch is F33 (10a).

0.5 BR/WS brown/white – boot light switch supply wire

UPDATE: I finally got around to opening up the loom and found that I had a blue wire that was broken. I stripped back the wire and soldered it back together and now the central locking works exactly as it is supposed to.

New Addition E36 Z3 Roadster 1.9

So it has been a busy few weeks here with regards to the cars. At the end of June I traded in the E39 530i Sport touring for the E70 X5 xDriver 40d. We have been so happy with the new X5, it is so comfortable, easy to drive and a great tow car. This left us with two X5 as I still had the E53 x5 3.0 sport. As the E53 was not being used so much since the E70 arrived, the decision was made to sell it on to a new home where it could be appreciated and driven. I had just come back from a few days away with a friend where we went to the Nürburgring and drove around the Nordschleife in a Vauxhall Vivaro van (an ex-AA van at that with a 60mph limiter) and went to the BMW Museum and BMW Werk in Munich.

During the hours of autobahn driving we discussed our cars, my friend having recently purchased a BMW E36 Z3 2.8. The discussions about our next possible trips and how it would be great to go around the Scottish North Coast 500 with the tops down.

As the E70 X5 really doesn’t need any work on it I needed a new project car. The new car would have to be a Z3 project car. The E53 X5 was sold and the money from this sale went to purchasing a cheap Z3 project car that was advertised on a Z3 facebook group.

From first impressions the car doesn’t look that bad. The wheels are non-BMW, a decat exhaust is fitted and the car is lowered by 30mm. It was only under closer inspection that the amount of work needed came to light.

On first impressions the hood looked in good condition, there was some rust in the usual places on the sills and the passengers back wing. There was water in the boot and there some were missing rubbers from around the windows (already sourced and replaced). The door locks will only operate from the central locking from the boot and there is a scuff on the front bumper. Not too much to work on. The car came with the original exhaust and springs so these are the first things to go back on the car once a full service has been completed.

I asked my local garage to do the majority of the work since I currently don’t have access to a garage or somewhere to jack up the car. The garage performed a once over and found the following items: –

  • Boy racer go faster air filter (already got the missing air filter box parts and put back to standard air filter)
  • Thermostat needs replacing (I noticed the temperature not rising during the test drive)
  • Front tyres with no rubber left on them, down to the bare threads underneath. Not an issue as new BMW Z star wheels have already been purchased which have nearly new tyres.
  • Power steering and brake pipes corroded.
  • Broken bolts holding exhaust on to manifold (not an issue as original exhaust going back on the car)
  • Handbrake needs adjusting (getting new brake fitted)
  • water in the boot looks to be coming from the rear light.
  • Digital clock has a couple of segments not working (not the end of the world but will be sourcing a replacement)
  • Gas struts on boot lid broken. Replacements sourced from eBay already.

At the time of writing, the car is in the garage having most of this work completed. New panels have been sourced in the car colour to replaced the panels that have rust, along with some spares for the future. New bumper has been sourced but will first look at repairing the existing bumper as I want to play.

The car has had an initial detailing. I find these really good to do as you get to know the car and find any other items that may have been missed. This highlighted that there is a hole in the carpet on the drivers side. This is hidden by the floor mats but will be replaced at some point. The engine bay has had an initial detail but needs more time. One of the items will be to repaint the BMW logo on the plastic engine cover.

I aim to post some updates on progress as I get through these items. The plan is to have the car in a reasonable shape for the start of the show season for 2020 followed by a week driving the North Coast 500 in September 2020.