Unreliable German Car on a Silly Journey

[JumpingFrog]

Final jobs from this repair-a-thon were a new thermostat and replacing the worn out rear shocks and springs (MOT is soon, and one spring looked pretty bad):

After that, drove a fair way across England, car behaved well and estimated range was over 700 miles at 52mpg, so new thermostat is helping. Checked the oil level on arrival, computer showed it was suddenly quite low so added 500ml. But the level didn't change at all... The difference between min and max is meant to be a litre. I definitely filled it with the right amount after its surgery. Best hunch is a bad level sensor, no way it could have burned 0.8L~ in <250 miles, and there's no signs of oil pooling on the undertray.


I'm also wondering if using graphogen on the big ends could be responsible for this as the sensor is apparently capacitive, but I would have expected most of that to have ended up straight in the filter, plus I only used a small amount... Remind me what is wrong with a dipstick again?

Edited July 9, 2024 by JumpingFrog

[Nick Jones]

1 hour ago, JumpingFrog said:

Remind me what is wrong with a dipstick again?

Too simple and 98% reliable. Double fail as viewed by German car designers (and JLR)….

[JumpingFrog]

Things were going quite well, after replacing a single injector last summer, I've been using it everyday for work and did almost 10k miles without anything other than a service.That was until yesterday, car sat for just over a week in an airport car park whilst we visited family in Russia. When we returned to it, it was idling roughly, but not awfully, made it back home okay despite ridiculous traffic (almost 3 hours for a 1.5 hour drive). Checked codes after getting back, fault code for cylinder 3 misfire.

Went for a nap (sorely needed after missing our connection in Baku and having to "sleep" in  a lounge), and then wanted to pop to the supermarket, BMW had other ideas. Running on 3 and sometimes 2, strong smell of raw petrol, fault code for multiple cylinder misfire.

Luckily I had the Standard, and that didn't seem to have much of an issue with having been left for a week, so made it to the shop, which was much more fun anyway. Plus I got to use the foot operated headlight dip switch in anger for the first time. The worn out paint work even looks good in the twilight

I've tried switching coil packs around and with my spares but to no avail, same codes for cylinder 2 and 3 misfire. Pulled all the plugs, they all look like its been running very rich, but cylinder 3 absolutely awash with fuel, so assuming that's the main issue. New injector on order, hoping I only need the one, but quite surprised as this has come out of nowhere, and usually these injectors fail gradually. Injectors are getting expensive, cheapest I can find is almost £500... They're of course dealer only.

 

[Nick Jones]

Bah!  £500 for an injector though…. Ouch!

Not enthusiastic about owning anything direct injection (petrol). Not that fond of common rail diesel either with similar technology witchcraft, uncertain longevity and replacement cost issues.

Hope this does the trick for you. Sounds like an oil change will be needed too.

My memories of Baku (from 1996) are very mixed. None positive from the airport though.

[JumpingFrog]

Whilst diagnosing it, it dumped so much fuel into the exhaust that it made a puddle on the ground. Good reminder that I need to replace that Flexi coupling at some point.

I've now switched cylinder 3 injector back with the less bad one I removed last summer. It runs better now, and is just about driveable, but started off with lots of smoke whilst it vaporised the petrol out of the exhaust... Code for cylinder 2 misfire disappeared, so it's probably the same thing with the ECU not being able to work out which cylinder in the bank is the bad one when something is seriously wrong.

Oil change is probably a good idea, I suspect there is a lot of petrol in it now.

GDI is not fun, and I really need to clean the ports up at some point soon, no doubt they're nasty.

[Nick Jones]

24 minutes ago, JumpingFrog said:

Oil change is probably a good idea, I suspect there is a lot of petrol in it now.

Indeed. Potentially enough to mess with the running and fuel trims due to fumes coming up through the crankcase breathing system.

[JumpingFrog]

On 5/24/2025 at 7:47 PM, JumpingFrog said:

Whilst diagnosing it, it dumped so much fuel into the exhaust that it made a puddle on the ground. Good reminder that I need to replace that Flexi coupling at some point.

This was foreshadowing, during the 500 mile trip to collect the Standard sub frame, the BMW decided its not happy with my lack of TLC. ECU is now throwing cat performance codes, engine is very hesitant at times and fuel economy is down about 10%. The flexi coupling sits between the cats and the downstream O2 sensor, so hopefully it's just that... If it's the cat, that's a very expensive fix that might exceed my desire to own the car. The MOT is due soon, so I really need to sort this out...



The whole exhaust is one piece (longer than above), as even the front repair section costs a fortune, I've just purchased the coupler... I guess I know what I'm doing this bank holiday weekend, bought some ER309L MIG wire for the occasion, since the exhaust seems to be 409 stainless. Also would like to tackle the gearbox seals while I'm at it, as they're dripping now. Going to be a pig of a job though, I'm sure of that.

Edited August 18, 2025 by JumpingFrog

[Nick Jones]

Elderly modernish German cars! You don’t have to be a masochist to own one (or more ), but is surely helps.

My (limited) understanding is that the post cat O2 sensor is really only to monitor cat performance and, while it’ll turn the money light on, doesn’t usually have much effect on running. I’m happy to be wrong though - good luck!

17 hours ago, JumpingFrog said:

that's a very expensive fix that might exceed my desire to own the car

Nice turn of phrase, gave me a (wry) smile….

This car should treat you better if it wants to live - most people would have sent it for bean cans a while back!

[JumpingFrog]

2 hours ago, Nick Jones said:

My (limited) understanding is that the post cat O2 sensor is really only to monitor cat performance and, while it’ll turn the money light on, doesn’t usually have much effect on running. I’m happy to be wrong though - good luck!

This is what I thought, but then this engine has the rather complex ECU with different injection regime. Allegedly, the ECU will disable the lean running regime that it uses the adjust fuel trims, which in the long term leads to rough running. The joint has been on its way out for a while, and I've been putting off fixing it for at least 6 months already.

It also seems to continuously (every 3 miles or so) try to "regenerate" the cat by running at lambda=0.97, which obviously hurts the wallet and probably isn't that good for the cat.

[Nick Jones]

Well, a cheap and relatively easy fix if it is that flexible joint.  Fingers crossed for you.

[JumpingFrog]

On 8/19/2025 at 4:30 PM, Nick Jones said:

Well, a cheap and relatively easy fix if it is that flexible joint.  Fingers crossed for you.

Not sure cheap and (relatively) easy would line up with my experience.

The mounting of the exhaust system is not so bad, once you've got the under trays off. However, the only flange nut that would undo was the easiest to access, as you can see, not much left of the nuts on the other two. Grinder got the bottom, the other was only possible with a dremel and carbide burrs.

Then once I had it off, I had to somehow drill out the old studs, which turned out to be incredibly hard and blunted the cobalt bits I'd bought for this job. Removing the gasket remains also took an age. From what I can see of the cats, I don't see any problems.

The repair section looked like this, and wasn't that cheap, but definitely preferable to trying to weld new flexi sections onto the old flange.


I'm not winning any awards for my welding, but welding stainless with 309 wire seems to behave very differently to mild steel, very spattery and heat builds up very quickly.

Then decided to fit the gearbox seals that I've noticed leaking for a while, output and selector shaft seals. Happily I didn't need to drain the oil for it. Then also refreshed the brake fluid since the computer was complaining that it hadn't been done. Hopefully its ready for an MOT now, didn't see any issues underneath, other than the usual BMW rear subframe rust, but didn't find any really bad spots. 

[egret]

Looks like a very productive weekend.  Fingers crossed on the MOT

[Nick Jones]

16 hours ago, JumpingFrog said:

Not sure cheap and (relatively) easy would line up with my experience.

Yeah, well…. It’s all relative! I know your pain, especially on the hardness of those broken bolts. Fear of the issue is why there is still a turbo sat in my office awaiting fitment almost two year after purchase. 
 

Good job done. FWIW I don’t bother with stainless wire when welding stainless exhausts. Standard stuff welds more nicely and in practice corrosion doesn’t seem to be a problem.

[JumpingFrog]

The ECU does seem happier after this repair, but it might be a placebo and I'm expecting something for my suffering and joint pain (concrete is not soft).

10 hours ago, egret said:

Looks like a very productive weekend.  Fingers crossed on the MOT

Toes crossed too, my experience of garages around Cambridge is less than stellar. Last year's experience was being charged £40 to bodge my head light bulb holder using wheel weights without my consent... Not debating the fault existed though (missing bulb retaining clip).

6 hours ago, Nick Jones said:

Good job done. FWIW I don’t bother with stainless wire when welding stainless exhausts. Standard stuff welds more nicely and in practice corrosion doesn’t seem to be a problem.

In hindsight this was a mistake, I think the reason stainless wire is hard to find and expensive is because everyone knows better than to use it? 409 not exactly corrosion proof to begin with. Apparently when welding stainless CO2 of any percentage in the mix is not ideal. Still, it seems to have come out more or less gas tight, just a bit agricultural in appearance.

Edited August 26, 2025 by JumpingFrog

[Escadrille Ecosse]

6 hours ago, Nick Jones said:

Good job done. FWIW I don’t bother with stainless wire when welding stainless exhausts. Standard stuff welds more nicely and in practice corrosion doesn’t seem to be a problem.

Wouldn't do it in my professional capacity but my amateur experience confirms Nick's view too.

[Nick Jones]

1 hour ago, Escadrille Ecosse said:

Wouldn't do it in my professional capacity

Nor I. Having been around the specialist welding associated with welding duplex and super duplex pump casings for offshore oil (what a bloody palaver!), and also food grade welding of 316 family alloys, I well know this is a rough old bodge.  

However, it works. I built the stainless Vitesse exhaust using this method over 15 years ago. Most of the welds are right up front, some even on the collector itself, so they get hot. Probably 50k miles too. And it’s all still fine.  I reckon the weld beads do end up as low grade stainless as the chrome and nickel from the base material mix into the weld pool.

[Escadrille Ecosse]

31 minutes ago, Nick Jones said:

welding duplex and super duplex pump casings for offshore oil (what a bloody palaver!)

Quite 

[Escadrille Ecosse]

37 minutes ago, Nick Jones said:

However, it works. I built the stainless Vitesse exhaust using this method over 15 years ago. Most of the welds are right up front, some even on the collector itself, so they get hot. Probably 50k miles too. And it’s all still fine.  I reckon the weld beads do end up as low grade stainless as the chrome and nickel from the base material mix into the weld pool.

Yeah. Much the same in my experience. I suspect you a right in your supposition about doping of the weld pool.

Edited August 26, 2025 by Escadrille Ecosse

[JumpingFrog]

So as I posted in the other thread, collision at a speed of at most 20mph, but result is:

• Both headlights broken.
• Bumper distorted and cracked in both corners.
• Front left wing badly crumpled.
• Front left suspension partial collapse. (more on this later).

Basically, someone pulled out on me without warning, and this deflected me into a parked car, hence the damage on both sides. Nobody was injured. I arranged my own recovery to my home to make sure the car didn't go off to a salvage yard never to be seen again.

Other driver's insurance admitted liability the next day (but I don't have that in writing yet). My car was written off as soon as I reported the incident. Since its written off and I accepted their valuation (but didn't receive payment), they told me I'm not eligible for a hire car (policy is fully comp.). On the other hand, I'm led to believe keeping the claim lean is best for future premiums? Either way, I'm left trying to sort this out and using the Standard for everything (almost 150 miles so far!), while no doubt, the person who caused this has a courtesy car as their car was only a few years old.

The most obvious thing broken was the alloy lower wishbone, which had fractured after being bent a surprising amount. This didn't worry me that much, as I'd heard of them fracturing on hard pot hole impacts esp. once 10+ years old, and this one was original. The anti-roll bar drop link was visibly bent too, again not really concerning.

The "tension strut" that resists braking force and laterally locates the wheel seemed to have sustained damage to its hydraulic bushing, which was leaking. I also separated the track rod end from the upright and rotated it to check it for bending, but it all seems straight. Wheel that was hit is obviously quite out of true, bearing seems okay, rotates smoothly and no play. No signs of damage or movement of the subframe either, or to the upright.


At first I thought this was all that was wrong. Since the arms and links were all original and had over 100k miles on them, I decided to just change the lot on both sides. But after doing so, I could tell something wasn't right once I dropped the car back onto its wheels.

Camber was way out on the passenger side. Looking again I found that the top mount had shifted inwards all the way to the end of the adjustment slots, and the factory camber locating pin had sheared off (circled). Removed the nuts, fortunately no tearing of the metal or signs of force or distortion to the tower.

But even that wasn't all, checking clearance between the wheel and shock, it was very close on the damaged side, so I wrestled the shock out, and then it was quite easy to see it was bent although only slightly (1-2 deg). This was more surprising, given the low speed of the collision, one would expect it takes serious force to bend a tube of this diameter.

So like the arms, I decided it's best just to replace both sides, which is a bit expensive, but I had already done the rears a little over a year back as they started to become a bit floaty. Hopefully it will at least drive like a new car?

Replacement parts required so far:

1. 2x used headlights.
2. Used passenger side wing - currently rust treating and touching up the inside arch with paint to stop it bubbling through in a few years.
3. Used passenger side wheel arch liners.
4. New front suspension kit.
5. 2x new top mounts.
6. 2x new shock absorbers.
7. 2x new springs and rubber cups.
8. Wheels and tyres, but these were planned already, eventually.

More than I expected, given it didn't look that bad at first, and I still need to find a bumper and investigate behind it. The devil is really in the detail with this stuff, the way the forces have been transferred are completely unpredictable despite being low speed, the direct hit to the wheel has no doubt made all this more painful.

Some more irony in this, I learned on Monday that my car has been recalled due to being fitted with a Takata air bag, so that could have been fun if it had gone off.

 

Edited 11 hours ago by JumpingFrog

[Nick Jones]

Surprised about the amount of suspension damage…..

Otherwise the front ends of modern (and modernish) car are incredibly “soft”. Audi used to supply headlight repair kits to restore the mounting points B that were invariably broken in the most trivial mishaps.

[mpbarrett]

No wonder cars are written off so quickly, that's a lot of labour to repair hence large costs..  Are you aiming to get it written off and then buy it back?

It does seem a terrible waste not to get it back on the road..... we have this push to go green and buy new but nothing to support reusing and repairing what we already have, but that's capitalism at its worse.....  ;(