E36 M3 3.0 engine issue

[tommy18]

Hi
I have bought a 3.0 m3 that's covered around 100,000 miles.
I knew that the car had an issue and this was reflected in the price. But now I have to find out just how major of a problem it is.
So basically the car starts cold fine other than sounding wooshy like the cooling fan is stuck on full. But no nocks etc.
When the car starts getting upto temp it cuts out. When you try to start it back up it struggles to crank over as if the battery is low but its not. Sometimes you'll be lucky and it will fire and start again but to quickly stall again.
I'd say the engine seems to get tight with temperature. Leave it 20/30 mins to cool and fine again for another couple of miles and it happens all over again.
There was a mention of the oil light flickering on idle but I've never seen it on.
Also checked the dipstick and oil filler cap during the sale and all good but after tinkering for 1hour yesterday we have some mayo on both.
The cars definitely unusable and has sat for 6 months.
Any advice would be greatly appreciated and I'm expecting the worse
Thanks again

[WilsonWilson]

See if you can get the codes read. Hopefully it is something electrical either the cam sensors or crank sensor and not lack of compression.

[HarryHill]

Mayo is not a good sign, especially on the dipstick. Short journeys will see it for on the filler cap, but the dipstick would indicate water mixing with oil on a more serious scale.

[Richair]

Start by eliminating the simple stuff first and go from there. Check the earth strap from the body to the block, as an iffy earth can give running issues and make it difficult to turn over (particularly when hot from experience...).

Is there much history of maintenance with the car?

[tommy18]

Thanks for your replies. Hopefully I'll get to spend some time on it tonight.
Service history is quite good, main dealer till 2007 then indi servicing from there. Theres nothing to make me think the mileage isn't genuine and the car looks to have been cared for.
The last owner was quite into his detailing and said 6 months ago removed the inlet manifold to clean and replace the alternator and hadn't used the car since. He's certain the problem is in that area and there is alot of connections and vacum hoses under that manifold.
He could be telling porkies but the car was not for sale. I pestered him on a forum to sell after a post of him showing it off. He seems genuine enough.
I know someone with oldskool bmw diagnostics so I'll get it ready.
Its just that engine sounding tight when warm that worries me. But there's nothing when I search for those symptoms on an S50
Thanks again

[e21Mark]

Where are you based? You could get a local independent to take a look or maybe, were you to 'break down', the AA/RAC could come take a look?

Now for the bad news, I have had similar problems a few years ago and it turned out to be the head gasket.