BMW 318TDS Whilst driving car pulls back to 20mph

Battery went flat on my bmw e46 saloon 05 no power to my dash board cluster turn the key no lights on at all .the only one is air bag

the relay is bad

what a lovely car real leather seats ,quiet engine state of the art for its time .Now for any jag to work properly you must first clean it ,treat the seats with a special cream every 3 mths ,then it will run forever but it does like being under cover in the garage with a sheet over it when not used ,do not bring it out when its raining either as it gets wet ,Now as for the overheating that should be no more than a thermo switch in the radiator which is cheap to buy ,about 10/12 euros ,make sure its filled with antifreeze or the heads will corrode in the water jackets .shouldnt have overheated whilst moving though even with no fan unless he was in heavy traffic with the AC on but even then the fan one of the two fans should run when AC is on.But on these vehicles mine is a 94 the AC fan doesnt come on whilst vehicle is moving only when the temperature in the front AC rad rises will fan come on ,Most off all enjoy this vehicle as its princess amongst cars and is a good investment for the future ,Also put you watch in the boot whilst driving as the ticking of the watch will drive you mad as its the only noise you hear whilst friving

check the vacuum hose from the inlet to the brake reservoir.......

if this is the 1.6 version then at this year its no doubt worn out ,well known for wearing out and burning oil .

DON'T DRIVE IT ANOTHER MILE !!!! Bet you have the 1.8t right ??These cars were known for a sludge buildup. DON'T DRIVE ANOTHER MILE !!! Google passat oil pressure and see how many pages come up

renew the flexible hose connections at the tank end if fitted and not a plastic pipe going straight to sender unit .Sucking in air problem is one of THEM jobs .a right pain to find 99%of the time .but any flexible rubber pipes can and do go porous with age

try removing battery and cleaning all the ground under the battery tray and check main ground wire from battery to engine

this can be adpative lights which is a special feature order on this vehicle

have oil level checked ,then when driving double the clutch as it sounds like a baulk ring,caused by hammering it into gear whilst going too fast trying to be a boy racer jeremy clarkson prodigy.second gear shouldnt be engaged whilst coming down the box at anything much over 20mph.expensive repair but driving with patience and a good driving technique it should last forever.