OV9

Explosive Newt wrote: Fri Feb 27, 2026 6:16 am Do they feel better now?
And when are you getting the M5 back?
This was simply the universe providing a silver car for you.

I'm so glad you asked !

Yes, the Merc brakes are VASTLY better. Not surprisingly. They are now normal again. Not only were the discs in a shocking state, all of the pads were seized in the calipers, I had to hammer them out. That was actually the first symptom, just at walking pace pulling out of the driveway the pedal needed a lot of pressure and took a lot of travel before anything happened. The grinding & wobbling didn't really show up until I was on the main road.

M5. Well. I think this car is going to cause me to start drinking again. First, the battery was flat when I got there, after sitting for three days. I'd accidentally left my code reader dongle plugged in but I don't think that should kill the fairly large battery that quickly. Fitting the hoses was painless thankfully. Hooking it up to a charger while I was working gave it enough to start again. I topped up another half litre of oil and headed home.

Just a few miles up the road it pinged up with a low coolant warning So I was now in a quandary, I didn't really want to stop and turn off the engine just in case it wouldn't restart, and the engine was already warm so I couldn't open the coolant filler to top up anyway. This engine seems to retain heat extremely well so it would literally take hours to cool down. I opted to wing it. The route home is almost all dual carriageway so I set the heater to max and the cruise control to 65mph aiming for a balance between low load on the engine, and decent airflow through the rads. I stared at the temperature gauge obsessively. It moved up & down a bit. But it's a real gauge on these, not the usual BMW heavily-weighted-to-centre-unless-something-is-very-wrong and it seemed to stay in the 90-100 range. All was going well until the traffic on the A3 came to an abrupt halt and we didn't move for a couple of minutes. This is not normal at 9pm on a Tuesday. A Police motorbike went past. We didn't move. We were close to the "on" sliproad from Bordon, a car came halfway down and stopped and was clearly assessing whether this was a good idea. I was getting anxious about oil & coolant. The other car cautiously reversed back up the sliproad. I decided "fcuk it, this is an emergency" and bumped over the grass to escape up the sliproad. You can't quite see the slip road here, it's not the bit that looks like a footpath, it's on the other side of the grass:


Arrived home, checked the oil level and it's still drinking it

Let it cool overnight, tried to check the coolant level but it has no markings and you can't see where it goes, you just have to pour some in, let it settle, then look if the surface is visible yet. I didn't measure but it kept taking more and more.... must have been 2-3 litres

I took it for a gentle drive last night and could see coolant dropping from the undertray when I got home. Managed to spot a leak from a hose near the thermostat. That was tricky enough as it was dripping onto the serpentine belt & spraying all over the place. Coolant in places high up on the front of the engine that should never see coolant. New thermostat was already on my list of things I'd like to do and is cheap enough for a reasonable (Febi) replacement. New hose from BMW is £64.54 I guess I'd better start getting used to this. I want to get under the car and remove all the undertrays to see if it's dripping from anywhere else. I can't see anything else from the top.

The oil consumption is looking increasingly like valve stem seals. A common problem. I did them on one of our MINIs and felt a little blasé about the idea, totally overlooking that this is not a MINI It's possible, but extremely fiddly, in-situ with a specially designed set of tools but they're $2k and need to be ordered form the US and I'm boycotting every American product I can right now:

https://agatools.com/products/n63tu-val ... 8429&_ss=r

Easier, and only a few hours' more labour, is to remove the engine, giving you all the access you need. And the opportunity to to do "while you're there" jobs like walnut blasting the intakes. Being a "hot v" the intakes are on the sides of the engine and basically impossible to get to normally.

Lots of stuff to move out of the way but not difficult, as such:





First I'm going to do compression & leakdown tests, and anything else I can to narrow it down. The nightmare scenario is damaged bores or broken pistons. I think that's unlikely though as it runs nicely otherwise. Currently earmarking the Easter weekend to get properly stuck in.

That said, it's in otherwise nice condition - paint & interior - and hasn't been messed with or neglected as such, it's just maintenance catching up with it. There's enough others for sale that look obviously sad and tired and this one isn't. Mechanical stuff I can do myself relatively cheaply. Paintwork OTOH, I can't. So for the price I paid it's probably OK. A lower mileage one for £20k will still (probably) have 12 year old valve seals that have gone hard and are leaking slightly and only getting worse.

Also, it makes a really nice noise I want to be able to enjoy it.

Oh no that's not good!

Were you aware of running issues when you bought it or is this all a nasty surprise?

I was not aware. The coolant leak I think is genuinely new, I looked all over the engine last weekend while breaking the vent hoses and didn't notice anything. The oil however, assuming it's the valve seals, the previous owner must have known about, as it produces a big cloud of smoke on occasion, like it did when it died and eventually restarted the day I collected it, and it would be asking for a top-up every couple of hundred miles.

It explains the attractive pricing for sure ! The parts for the job are only a few hundred quid: a SEAL KIT plus a few incidentals but there's a massive amount of labour so at a specialist it’s pretty pricey, e.g. HERE is £3,540 (possibly +VAT, not clear, but their other listings for engine rebuilds are +VAT). So that's £4,248 - I'd be saving myself ~£4k.

Explosive Newt wrote: Fri Feb 27, 2026 6:15 am
Is it a standard 18 inch wheel? They are surprisingly cheap. I got a new one from Tesla rather than repair when mine cracked as I was a bit skeptical about a weld repair on it.

It’s the 20” wheel.

Sundayjumper wrote: Fri Feb 27, 2026 10:37 am I was not aware. The coolant leak I think is genuinely new, I looked all over the engine last weekend while breaking the vent hoses and didn't notice anything. The oil however, assuming it's the valve seals, the previous owner must have known about, as it produces a big cloud of smoke on occasion, like it did when it died and eventually restarted the day I collected it, and it would be asking for a top-up every couple of hundred miles.

It explains the attractive pricing for sure ! The parts for the job are only a few hundred quid: a SEAL KIT plus a few incidentals but there's a massive amount of labour so at a specialist it’s pretty pricey, e.g. HERE is £3,540 (possibly +VAT, not clear, but their other listings for engine rebuilds are +VAT). So that's £4,248 - I'd be saving myself ~£4k.

I wholeheartedly support your decision to pull the engine and go all M539 on it. If it is a help I'll gladly come by one Saturday to drink your coffee and pretend I can be helpful while watching you work.

I'm not a fan of the Hot V engines, one of the biggest issues we have on our big stuff is lack of ventilation areas. It lets everything cook for hours after you shut down and we then have weird failures.

It was an E63 where it was shut down and an hour later measured 150 degrees or something behind the headlight!!! Plus turbos absolutely hate stagnant oil and hot bearings for the same reason.

As people actually work on BMWs I wonder if there is a good write up showing common failure parts, hoses, heat shields etc when the engine comes out ?

Dave!

DeskJockey wrote: Fri Feb 27, 2026 1:31 pm

Sundayjumper wrote: Fri Feb 27, 2026 10:37 am I was not aware. The coolant leak I think is genuinely new, I looked all over the engine last weekend while breaking the vent hoses and didn't notice anything. The oil however, assuming it's the valve seals, the previous owner must have known about, as it produces a big cloud of smoke on occasion, like it did when it died and eventually restarted the day I collected it, and it would be asking for a top-up every couple of hundred miles.

It explains the attractive pricing for sure ! The parts for the job are only a few hundred quid: a SEAL KIT plus a few incidentals but there's a massive amount of labour so at a specialist it’s pretty pricey, e.g. HERE is £3,540 (possibly +VAT, not clear, but their other listings for engine rebuilds are +VAT). So that's £4,248 - I'd be saving myself ~£4k.

I wholeheartedly support your decision to pull the engine and go all M539 on it. If it is a help I'll gladly come by one Saturday to drink your coffee and pretend I can be helpful while watching you work.

I like this. I'm free too. We'll all come down and "help".

Explosive Newt wrote: Fri Feb 27, 2026 2:44 pm

DeskJockey wrote: Fri Feb 27, 2026 1:31 pm

Sundayjumper wrote: Fri Feb 27, 2026 10:37 am I was not aware. The coolant leak I think is genuinely new, I looked all over the engine last weekend while breaking the vent hoses and didn't notice anything. The oil however, assuming it's the valve seals, the previous owner must have known about, as it produces a big cloud of smoke on occasion, like it did when it died and eventually restarted the day I collected it, and it would be asking for a top-up every couple of hundred miles.

It explains the attractive pricing for sure ! The parts for the job are only a few hundred quid: a SEAL KIT plus a few incidentals but there's a massive amount of labour so at a specialist it’s pretty pricey, e.g. HERE is £3,540 (possibly +VAT, not clear, but their other listings for engine rebuilds are +VAT). So that's £4,248 - I'd be saving myself ~£4k.

I wholeheartedly support your decision to pull the engine and go all M539 on it. If it is a help I'll gladly come by one Saturday to drink your coffee and pretend I can be helpful while watching you work.

I like this. I'm free too. We'll all come down and "help".

We could stretch the legs on all his other cars so that he doesn’t have to worry about them and can focus on the M5! You chaps are selfless heroes!

I’ve been reading up about the balancer shaft sprocket issue our merc ‘should’ be afflicted with. Watched a few videos and started thinking that pulling the engine out doesn’t actually look that tricky.

If anything, modern cars seem to be more modular that older ones, if you’ve got the time and space pulling an engine out isn’t really that scary….

It does open you up to a massive list of ‘while you’re there’ things and an every growing parts bill!

Bit of a bummer to have to consider it on something so new to you, but guess that’s just the risk we take buying at the lower end of the market.

Anyone else and I’d agree with you Harry, but I think Steve thrives on this sort of stuff.. how long did he own the 360 before it was in bits, a week?

integrale_evo wrote: Fri Feb 27, 2026 6:51 pm ...but guess that’s just the risk we take buying at the lower end of the market.

'Lower end' IIRC Steve's M5 was the lowest priced F10 in the UK, and high mileage too. And yes, @IanF I think that's all part of the fun for him

Had a great blast today, mid-afternoon from Edinburgh down to Newcastle via the A68 and A696, the latter of whcih was spookily quiet and good fun to drive. Fairly fast, clear sight lines, open corners and no speed cameras. Spent most of the time whizzing up down and around the curves and yumps along there. Wish there were roads like that near me at home!