New owner, predictable problems

[Sundayjumper]

Yes, I failed my due diligence, yes, it was cheap, yes, I've possibly made an expensive mistake 🤣 It broke down on the way home from collecting it. It managed 35 miles of a 90 mile journey.

But it looks nice. I like the anonymity; it could almost be 520d unless you knew.

November 2013 LCI with 120k miles and apparently FSH.

It is showing what I so far believe to be classic valve stem seal failure. Runs & drives OK but guzzles oil. Left idling it gradually starts to emit smoke from the exhaust and then when you take off there's a huge cloud of it. Doesn't smoke on startup (which would be injectors ?) or when moving and suddenly hoofing it (turbos, rings ?). It had 8x new coils just before I bought it. I've already done the 2x breather hoses. I have 8x spark plugs ready to go in. I'll do compression & leakdown tests first though to hopefully eliminate the nightmare scenarios. I've not had an F10 M5 before so to be sure I wanted to check:

Compression. Is this the same as any other car - remove fuel pump fuse, remove all spark plugs, spin the starter for a second or two ? Will the car throw a wobbly when it doesn't start after a couple of tries ?

Leakdown. Must it be done at TDC ? Anywhere on the compression stroke would work, I think ? Is there a smart way to determine TDC or do you just stick a screwdriver down the open spark plug hole and turn it (slowly, clockwise) with a bar on the end of the crank ? Turn it 90° and move to the next cylinder in the firing sequence ?

The tools are on the way to do this in the next few days.

If that all checks out I think we're onto the valve seals. Have any of you guys done this job:

* DIY
* With the engine in the car
* Without using the $$$$$$$$$$$ AGA toolkit

I'll pull the engine to do it if I have to. It looks dead simple once the engine is out.

FWIW I'd call myself an experienced DIYer, I'm not afraid of a spanner. I'm well kitted with tools & stuff and I do all my own work on my 360, but that's quite crude tbh. The F10 is super high-tech by comparison !

[KurtsM5]

I think the only qualified active member here is maxist

[KurtsM5]

I will also say you should get liqui.moli oil saver and syracote.
And substitute that for quart of oil. That stuff killed my oil consumption.

[Sundayjumper]

Originally Posted by KurtsM5

I will also say you should get liqui.moli oil saver and syracote.
And substitute that for quart of oil. That stuff killed my oil consumption.

Thanks. Is the Liqui Moly better than Sea Foam ? I've seen that recommended a few times.

[KurtsM5]

I don't know anything about sea foam.The oil saver restores dried out valve stem seals.

https://www.fcpeuro.com/products/lub...xoCcSIQAvD_BwE

[Sundayjumper]

Sounds ideal ! I've ordered some locally.

[Sundayjumper]

Thinking on about valve stem seals, how much of a job is it to pull the heads while the engine is in the car ? Compared to pulling the engine *then* pulling the heads ?

One of the "while I'm there" jobs with the engine out would be walnut blasting the valves. You can obviously do a better job of it with the heads off and actually removing the valves to clean them. If the heads are coming off anyway maybe I don't need to remove the whole engine ?

OTOH I'm always wary of removing cylinder heads as there is always the risk of stripping a thread in the block when you bolt them down again.

[M5_Raz]

Looks nice, congrats! I’d recommend to drive it until you use a few quarts of oil, while you top off after every fill up, or as needed. Per BMW, it’s normal for these engines to burn up to a quart per 650-700 miles.

If you’re over that, then consider it normal and save the money for those expensive repairs until later. Otherwise, consider keeping up more diligently on your oil to be at max level or close to it or do the repairs.

Most of these engines burn oil to some extent, as do most turbo engines.

[Sundayjumper]

I ran Sea Foam for 190 miles and drained it today. Looks like it has cleaned some muck out of the system. It was serviced 1500 miles ago (not me - I've had it less than 500) and the oil was pretty black. Refilled with Mannol 5w40 & two cans of that Liqui Moly Oil Saver. Service history says "10w40" for the last couple of services but not which brand.

Fitted new spark plugs & air filters. Service history says they were both 24k miles old. Seems crazy to leave the air filters so long when they're so cheap and so easy ? Plugs mostly looked OK but #6 was a little dark and #2 definitely blackened. Is that valve seals ? Injector(s) ? Injectors are more expensive on the parts cost but a lot less labour.

I'm also scaring myself reading about rod bearings 🤣 If I really have to, then engine out & all of these jobs in one go is on the horizon.

[KurtsM5]

Originally Posted by Sundayjumper

I ran Sea Foam for 190 miles and drained it today. Looks like it has cleaned some muck out of the system. It was serviced 1500 miles ago (not me - I've had it less than 500) and the oil was pretty black. Refilled with Mannol 5w40 & two cans of that Liqui Moly Oil Saver. Service history says "10w40" for the last couple of services but not which brand.

Fitted new spark plugs & air filters. Service history says they were both 24k miles old. Seems crazy to leave the air filters so long when they're so cheap and so easy ? Plugs mostly looked OK but #6 was a little dark and #2 definitely blackened. Is that valve seals ? Injector(s) ? Injectors are more expensive on the parts cost but a lot less labour.

I'm also scaring myself reading about rod bearings 🤣 If I really have to, then engine out & all of these jobs in one go is on the horizon.

I used to need a quart by 2500 miles. Since this last change when I added liqui moly oil saver and a can of liquid moly ceracote, I'm at 2k miles and still full. Game changer.
I am convinced that these low mile cars sat in the garage most of their life and the valve stem seals dried up.

[Sundayjumper]

Mine is definitely not low miles ! 121k and counting.

Anyway, we did another trip to my parents' place over the weekend, 150 miles total, and it's used half a litre of oil. That's roughly 10x the quart per 2500 miles you were seeing. I don't doubt the Liqui Moly. I just suspect that my seals are too far gone for it to be able to help. If anything the smoke when pulling away after idling for a bit seems worse after draining the Sea Foam.

Here's pics of the spark plugs, FWIW. The white crusty I am assuming is ash from the oil that has burned off ?


Plugs 1-4



Plugs 8-5




#2 is the one that stands out as being very blackened. #6 a little bit. I can't tell if it's just the weakest plug and about to fail totally and not igniting properly, or maybe the injector is over-fuelling. I fitted all new plugs before the trip at the weekend and can't say the car felt any different or better for it. No error codes and all eight coils were brand new (Bosch) a week before I bought the car.

I'll do a few more miles this week but I have little confidence now. I'm drawing up my parts list to spend Easter pulling the engine out.

[KurtsM5]

Gotta give the oil saver time, man. Not instant.

[Sundayjumper]

Another 150 miles down, still no difference. The engine's coming out.

[rainyM5]

I have something very similar going on. Something to consider:

https://f10.m5post.com/forums/showpo...33&postcount=9

Originally Posted by rainyM5

I also would lose a lot of oil and would need to top off frequently. I went through everything commonly recommended to replace, pcv and so on. I also used Liqui moly leak stop and similar products. It seemed to help very little.

When I switched to catless downpipes, I noticed dark smoke from my exhaust that was getting noticeably worse and more frequent. I brought it to the shop to have the smoke looked at. They were able to source it back to a leaking Turbo Oil Return Cover. The part itself is not pricey to replace, it's the labor that adds up because of where it is located.

[Sundayjumper]

Originally Posted by rainyM5

I have something very similar going on. Something to consider:

https://f10.m5post.com/forums/showpo...33&postcount=9

Interesting. Anything that's easier than removing the engine is interesting right now !

I've not seen that part mentioned before. How did they diagnose that as being the problem ? What is the effect, it sucks too much air into the crank case like a leaky PCV ?

[Sundayjumper]

And did the new cover fix it ? It’s not entirely clear from your post !

[M5Rick]

I could be wrong but I think he's talking about the turbo oil return unit which is below the exhaust manifolds that need removing to get to it if its leaking oil into the V.

[Sundayjumper]

Yes, he is.