E46 Cooling System Overhaul

[c3m]

Hi guys,

I'm facing a bit of a dilemma about what to do - my E46 330Ci has developed a slow coolant leak. It has become worse over time - at the moment, if I go for a 30-40min drive (25 miles), the coolant level as indicated by the stick would go from max to just above min.

I've done my background reading and know the coolant system on these cars are a weak point - mine is approaching 80k miles. As far as I can see, I have the following options:

1) Try to locate the problem and only replace the affected parts
2) Do a complete overhaul of the cooling system

I'm pretty fond of my car and have no interest in changing it in the near future, so I'm thinking I should just invest and do a complete overhaul. I've got the following parts on my list to get replaced:

- Coolant Expansion Tank
- Radiator
- Water Pump
- Hoses (top + bottom)
- Belts
- Thermostat
- Coolant Cap

[OPTIONAL]
- Main belt
- Alternator Deflector Pulley (idler pulley)
- Main Tensioner Pulley
- A/C Pulley

I'm not an expert but replacing the optional parts seems a bit excessive - what do you guys think?

Also, does anyone know how much such an overhaul would cost? I live in the Sevenoaks, Kent area - can anyone recommend any BMW specialists close by? I was thinking of taking it to ETA Motorsport at Brands Hatch.

Thanks.

[c3m]

33740 said:

I'd locate the problem first and go from there. It could be a head gasket or a cracked block!

Would there be any way to even locate the leak when it's losing so little coolant?

[c3m]

Thank you all for your advice.

Alex88 said:

c3m, my e46 is going into my local BMW indie today for the same work.

I live in Herts so probably not convenient for you, but I'll happily let you know what the cost was and what was done.

That'd be great, Alex!

broken biscuit said:

Why not go for a drive, get the car nice and warm (so the rad is flowing water) then get home and park it on a big sheet of cardboard?

Unfortunately, the car lives on the street and with the current wet weather, it will be hard to do - thanks for the suggestion, I'll keep it in mind.

[c3m]

Alex88 said:

Hi c3m, sorry for the delay in replying.

I haven't got my bill with me, but I'll check it when I get home to make sure I've got this right.

Thanks, Alex - that's super useful!

[c3m]

RyanTank said:

Have you had your local spanner monkeys do a pressure test on the system yet?

Not yet, it's booked in next Thursday, will update the thread once I know more.

RyanTank said:

One thing they did explain was that there may be a need to drain the A/C system to get the rads off.
Something worth bearing in mind for cost of a refill too.

Thanks, will keep it in mind.

[c3m]

Quick update - the car was put on a lift so that we could take a look underneath. Two components were identified which were leaking: bowing radiator and water pump. Booked in to get it fixed next week, quite happy to properly take care of the cooling system so that I'm not constantly thinking when it's going to leave me stranded on the side of the road.

[c3m]

Thanks for the advice, guys. I'm getting the following parts changed (OEM BMW) next week:

- Coolant Expansion Tank
- Radiator
- Water Pump
- Belts
- Thermostat

I've replaced so many things on the car over the past 3 years, hoping not much comes up for a while.