Z4 Cooling System

[edd_jedi]

I've had many BMWs over the years including E36s, a Z3, and E39s. One thing common to every single one of them is catastrophic cooling system failure! All of these cars at some point during my ownership caused me at least a roadside breakdown due to over heating, usually due to water pump, thermostat or radiator failure. And my first E36 suffered head gasket failure. The mileage and age of the cars ranged from 5 years old and 50k miles onwards, so I wasn't just buying old dogs either :lol:

On many other forums, BMW cooling system parts are pretty much considered as service parts which should be replaced at regular intervals. But this is the most modern BMW I've owned, so I'm just wondering if anybody can give me an idea on the reliability of the cooling system. I am tempted to just replace the lot for peace of mind, but then I don't want to blow £3-400 if it won't be of benefit.

 

[ranski]

My car is currently having the O rings changed on all the radiator pipes/hoses

I noticed a leak a few weeks ago that has worsened. On investigation two pipes were leaking, well the quick release sections

The car is 10 years old so I guess the rubber components are reaching end of life

 

[bcworkz]

I'm afraid it's still not the best, I've heard of thermostat and pump failures and overflow tank leakage at the hose connections is a common issue, the design of this portion is pants. At least when it's working properly it seems to keep the car at temperature no matter the weather. I'm sure there's owners who have had no issues at all, so it could be worse.

 

[mmm-five]

Not had any problems in 90k miles on mine.

What do you use to top it up/refill it when it needs a coolant change?

 

[edd_jedi]

What do you use to top it up/refill it when it needs a coolant change?

BMW sell their own coolant concentrate for about £7 a bottle. I must have bought a dozen of them since I got my first BMW back in 2004

 

[mmm-five]

What do you use to top it up/refill it when it needs a coolant change?

BMW sell their own coolant concentrate for about £7 a bottle. I must have bought a dozen of them since I got my first BMW back in 2004

That's why I was checking, as some people top it up with tap/mineral water and end up furring up the system with mineral deposits.

I think I took about a pound of crud out of my M5 when I did an overhaul soon after buying it.

 

[Zeld4]

What do you use to top it up/refill it when it needs a coolant change?

BMW sell their own coolant concentrate for about £7 a bottle. I must have bought a dozen of them since I got my first BMW back in 2004

When I went in to BMW to find out what coolant to top up with the service manager said just use normal water for a top up! Was he talking shite?

 

[mmm-five]

When I went in to BMW to find out what coolant to top up with the service manager said just use normal water for a top up! Was he talking shite?

You're supposed to use denatured/distilled water to stop it get any containments in it, but in an emergency I don't think it will matter if you put a litre of pee in there (just wait for it to cool down)

You shouldn't however do a complete coolant change with tap water & coolant.

The crap builds up and restricts the flow, reduces the cooling pack performance and can cause corrosion on seals, pump, thermostat parts.

 

[Liquid]

I've always used distilled/deionised water and BMW coolant.

After having a cooling system issue thanks to corrosion in my E31, it's clear to see that chucking any old water and/or coolant in isn't the best for your system.
Given the cost of the water and correct coolant, you'd be daft to do anything else.