Llew's F90 M5

This post triggered me a little.I did my apprenticeship from 2017-2021 at Key in kzn and I cannot fathom signing off a job card knowing full well that I didn't perform the work that was expected of me.

Greenz said:

This post triggered me a little.I did my apprenticeship from 2017-2021 at Key in kzn and I cannot fathom signing off a job card knowing full well that I didn't perform the work that was expected of me.

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The comments on TikTok and my DMs suggest this is unfortunately a fairly common problem - my guess is especially on V8s where it may be donkey work? I can't imagine the workshop foremen are checking over basic things like spark plugs - more worrying about whether the appies are not messing up bigger/higher stakes jobs. This is the only working theory that makes any sense.

Compared to the F90, the G90 does feel a bit hit and miss. Its insanely quick for something as heavy as it is, but it doesn't feel fun at all to drive. The F90 really was peak BMW M car of the turbo generation, I'd hold onto this if I were you for life.

I went for a ride in the G99 Touring and its absolutely massive. Feels like you in a boat on wheels. Don't really like the way it looks either as its giving too much of Mercedes R Class Vibes from a few years back which was more or less designed to be a hearse.

Nishcat_M140i said:

Compared to the F90, the G90 does feel a bit hit and miss. Its insanely quick for something as heavy as it is, but it doesn't feel fun at all to drive. The F90 really was peak BMW M car of the turbo generation, I'd hold onto this if I were you for life.

I went for a ride in the G99 Touring and its absolutely massive. Feels like you in a boat on wheels. Don't really like the way it looks either as its giving too much of Mercedes R Class Vibes from a few years back which was more or less designed to be a hearse.

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Amen, never sell that thing

F90 Time:

This has cost an average of R42000 a year including all performance, cosmetic and out of warranty items INCLUDING motor plan extensions, which I feel you have to include. Using the very scientific method used in the Alfa thread, this is 'two car installments' at current value and just under 1 car payment for a G90 M5 on the beloved 72 months 30% residual model or 30% less than 1 'actual' G90 installment (ie 60 months, no residual)

In "reality" this again more like a R23K per year car to run if you take out all my adventures with suspension, cosmetics, CS bits and forged wheels.

I have said many times, you can own an M out of plan with no car payments OR WITH car payments but it should then have plan. I hope it is evident why this is the case

Not covered here are brake discs (these were changed in 2025 but I didn't have the invoice for it - it would be on the CIA) as well as the headlight that was replaced under plan for having a blown DRL LED driver. It also includes the supply of the wrong tyres that the workshop then just blindly fitted (Pilot super sports instead of PS4S) and they gave me a letter to state that there would be no issues with motorplan since they supplied them LOL. It irritated me not having matching front and rear and then afterward they could only supply PS4S or P Zero Corsas for my rears so I just sold the fronts and did the P Zeros which are on the car until now

That being said, BMW is often consistently the cheapest on tyres and on oil services somehow. I will also say that between brakes, my light change and a few other items, I got plenty of value out of those plan extensions (not changing plugs and half-assing the coolant bottle job notwithstanding).

One more maintenance update:

With 10,000 km to go on the CBS indicator, of course it was time for an interim oil change.

I had been playing with the idea of a switch to Motul as well as to 5W-40 oil. The typical OEM BMW dealer oil is a 0W-30 (LL-01 FE), which is heavily optimized for US fuel economy and emissions as opposed to heat resistance and bearing protection. Direct-injection engines also face the risk of Low-Speed Pre-Ignition (LSPI) something the S63 in the F90 is NOT totally immune to. There is also oil thinning due to unburnt fuel dilution (and over an absurd 20,000 km factory service interval, that becomes a serious concern for bearing wear).

There are numerous claims online that the F90 isn’t specced for 5W-40, but this is simply not true. US threads frequently state that the car needs to be rebuilt with bearing clearances to support 5W40 but European and German manuals approve 5W-40 for hotter operating conditions. The US mandates 0W-30 for emissions and compliance.

Lo and behold, our very own South African owner’s manual lists (on page 335) 5W-40 as a fully approved spec LOL. Before anyone comes at me for this, bear in mind I didn't blindly experiment here. As with anything oil-related, it’s practically religion or politics!



A 0W-40 requires wider viscosity index improvers to achieve that spread, which can make it more prone to mechanical shear under load. The "zero" in 0W40 only really becomes cruicial below -20 (or consistently freezing temperatures). Not something we have even during a JHB winter. Together with our local warm climate and track-duty temperatures, 5W-40 was the obvious sweet spot.

I opted for Motul once again (Alfa and Porsche are also Motul...



(I am awaiting my Motul sponsorship... any day now... like my Hogwarts letter)

I may still switch to 300V down the line depending on how the car gets used, but what tipped the scales toward X-cess was its BMW LL-01 manufacturer approval and the other required manufacturer certifications/detergent package for road use.

A few other M owners have made this swap as well.

So, off I went to Deago to grab an OEM oil filter, and then the car went to Clint at MMS Auto for the oil change.
(SUPER quick actually!)

I may have missed it, but you are wanting an SP-rated oil to reduce to risk of LSPI. The SP-rated Motul 5W 40 that I use is the X-cess Gen II. Gen I is not SP-rated, as far as I recall

ajm said:

I may have missed it, but you are wanting an SP-rated oil to reduce to risk of LSPI. The SP-rated Motul 5W 40 that I use is the X-cess Gen II. Gen I is not SP-rated, as far as I recall

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To add: API SP cert/stamp still does not eliminate risk of LSPI entirely but does mitigate it from oil being the source. There are really four horsemen of this LSPI apocalypse:

1. Fuel dilution: The risk still builds over time with fuel dilution. The only solution is still to run short oil change intervals on this one.

2. General carbonation over time which later in the engine's life causes it to build on piston tops and back of valves. You could probably run water/meth early enough in the car's life to protect against some of this. The S63tu is not as bad as other motors but it still happens. If not you can run cleaners for the injectors and piston tops and wait to inevitably walnut blast (or otherwise clean) the backs of the valves.

3. Emissions and Economy I guess? LOL - this should probably be #1 in importance: The way these cars are geared and their shift logic to get up to very high gears and reluctance to kick down exacerbates this phenomenon in comfort modes. Even in Sport and Sport Plus it still wants to keep the car in a high-ish gear (not that the car is short of torque in those gears, but this is the scenario of being between 1500 and 2000rpm under high boost/load that will trigger it). This is what B58s tend to exhibit as well.

You can adapt your driving style to a degree here.

4. Hot V heat: The sheer heat degrades the oil and the additive mix breaks down (including the modifiers to allow for 0 rating). xW30 can end up extremely thin where 40/50 still offers a fair bit of protection, even broken down. This is a bit of a mix of all the above. Only solution is shorter oil change intervals again.

There is no getting around a 7500 to 10000km interval for a DI car.

I will add these to the F90 guide as well.

TurboLlew said:

To add: API SP cert/stamp still does not eliminate risk of LSPI entirely but does mitigate it from oil being the source. There are really four horsemen of this LSPI apocalypse:

1. Fuel dilution: The risk still builds over time with fuel dilution. The only solution is still to run short oil change intervals on this one.

2. General carbonation over time which later in the engine's life causes it to build on piston tops and back of valves. You could probably run water/meth early enough in the car's life to protect against some of this. The S63tu is not as bad as other motors but it still happens. If not you can run cleaners for the injectors and piston tops and wait to inevitably walnut blast (or otherwise clean) the backs of the valves.

3. Emissions and Economy I guess? LOL - this should probably be #1 in importance: The way these cars are geared and their shift logic to get up to very high gears and reluctance to kick down exacerbates this phenomenon in comfort modes. Even in Sport and Sport Plus it still wants to keep the car in a high-ish gear (not that the car is short of torque in those gears, but this is the scenario of being between 1500 and 2000rpm under high boost/load that will trigger it). This is what B58s tend to exhibit as well.

You can adapt your driving style to a degree here.

4. Hot V heat: The sheer heat degrades the oil and the additive mix breaks down (including the modifiers to allow for 0 rating). xW30 can end up extremely thin where 40/50 still offers a fair bit of protection, even broken down. This is a bit of a mix of all the above. Only solution is shorter oil change intervals again.

There is no getting around a 7500 to 10000km interval for a DI car.

I will add these to the F90 guide as well.

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Yes, this all sounds correct. On the s63 platform, the smart move is to run an SP-rated 5w40 - I see some guys even go to 5w50 - and to do frequent oil changes - I wouldn't go much past 6,000kms. Getting the oil analysed every once in a while, is also not a bad idea