BMW 320i touring overheating

[LeviM]

I have a 320i touring 2006, drives great but after driving for 40 minutes the car will start to overheat. Let the car cool down and it will be okay for another 40 minutes

Had a look under the car and no coolant leaks but there is a slight oil leak so I’m not sure what’s wrong

Anyone have any idea on what to check When I have another look at it?

[miniman]

Thermostat.

[Athlon]

Impeller slipping on the shaft in the water pump? Was common back in the day, or has been said the stat.

When it gets hot check the temp of the coolant hoses, both rad hoses hot it's not the stat, one hot one cold probably is, both cool it's the pump.

[Touring442]

It's an N46 so the water pump is on the back of the PAS pump. They very rarely fail. The thermostat is part of a plastic housing bolted to the side of this, quite tricky to get to. It's normally a horrid oily mess down there.
There is a coolant hose that goes from the top of the pump/stat that goes to the front of the cylinder head. The plastic stub that goes into the head will be brittle and easy to break at this age, and those benevolent souls at BMW will only sell you the complete hose, bless. It's all snap fit hoses on these as well.

I would replace the pump, stat and that hose.

This is a good guide:

https://www.newtis.info/tisv2/a/en/e87-120i-sha/re...

[Pica-Pica]

E36 was notorious for the plastic impeller on the water pump breaking at higher mileage. So It could be that repeated on later models. Replace with metal one, and replace thermostat and gasket while at it. Make sure the radiator is fully vented after refilling. Drive around the block, re-vent and top-up coolant - repeat a few times until level is stable.

[helix402]

Check the fan works as these are prone to failing due to the box of electronics which are part of the fan failing.

[Touring442]

Corrosion where the wires go into the box, common enough.

[LeviM]

Thanks everyone for the replies, not sure if this well help with me a diagnosis or completely something else.

Just been started up and there was a smell of oil and slight oil coming from the exhaust, and the heater is not very strong

Any ideas ?

[LeviM]

helix402 said:

Check the fan works as these are prone to failing due to the box of electronics which are part of the fan failing.

Fans work but the heater is very weak now

[RUSSELLM]

LeviM said:

helix402 said:

Check the fan works as these are prone to failing due to the box of electronics which are part of the fan failing.

Fans work but the heater is very weak now

Sorry to sound stupid.... But are you saying the cooling fan (Radiator fan) is kicking in ? If so, after how long ?

[Touring442]

LeviM said:

Thanks everyone for the replies, not sure if this well help with me a diagnosis or completely something else.

Just been started up and there was a smell of oil and slight oil coming from the exhaust, and the heater is not very strong

Any ideas ?

Sounds like it's shagged to be blunt. Check the oil and coolant levels but if it's overheating and smoking, it's future isn't very bright.