Starting after a lay up

[NDA]

I haven't driven one of my cars since September - it's been tucked up in my garage on a battery tender. It has a 4.8 BMW V8 under the bonnet.

I probably won't drive it for a while yet, so it could be 5 months or so sitting idle.... I suspect modern engines will cope OK with this, but might there be anything I should do before spinning the engine up?

It's impractical for me to reach all the spark plugs as I'm not a gynaecologist.

[Depthhoar]

4.9 litre V8 owner here who also lays his car up for 6 months of the year.

I reconnect the battery, remove the fuel pump relay and spin the engine over until the oil light goes out. Then I do it again. Finally, I re-insert the fuel pump relay and fire it up. It always starts like a startled rabbit. Seems a good way of circulating engine oil without the huge mechanical stresses brought about by combustion. It's at exactly this moment that I realise what a glorious sound a flat plane V8 makes at a cold start. And how much I've missed it!

I'm one of the many M5 owners who worry about the condition of the rod bearings....but probably without good reason in the case of the S62 engine.
Good to be cautious though!

[NDA]

I'll pull the fuse for the fuel pump..... this means the engine turns/cranks but without fuel?

Thanks

[Depthhoar]

That's it.

If there's some residual fuel pressure in the fuel lines then it'll try to fire at first but then immediately afterwards just spin without combustion.

[NDA]

Cool... will do that.

In one of my cars it had a specific routine for it. Floor the throttle and keep it down and hit the start button. I was a bit anxious the first few times!

[itiejim]

Depthhoar said:

It's at exactly this moment that I realise what a glorious sound a flat plane V8 makes at a cold start. And how much I've missed it!

Which if course it does, but your M5 is a cross plane crank V8 unless it's a very special one-off 👍

[Old Merc]

I`ve been storing my Mercedes R129 every September to April for over ten years,never a problem. Every couple of months when there is a nice dry day I charge the battery, start the engine and move it out into the drive. As we live in a quiet close away from main roads,I can drive it (SORN) for a 100yds or so up and down the close. Back in its warm garage,all covered up with the battery disconnected. Roll on the spring.

[Depthhoar]

itiejim said:

Which if course it does, but your M5 is a cross plane crank V8 unless it's a very special one-off ??

Good catch! After a bit of Googling it certainly appears you're right. Every day's a school day!