Coolant System

[Dunkelgrun]

Hi Z3 experts, I’ve heard that bmw’s tend to have cooling system issues, like the plastics tend to degrade and then cause problems. Any thoughts on that? I have a nicely running 98 2.8 prefacelift, manual, 76,000 miles. It was well maintained and garaged, but I don’t see any evidence that any cooling system parts have been replaced, other than the coolant itself which is clean and blue.
Should I be considering replacing any or all cooling system parts as prevention, or leave well enough alone? Should I consider the “clutch fan delete”? Any suggestions would be much appreciated.

 

[Dino D]

Sounds just like mine when I bought it - similar miles when I bought mine 11yrs ago.

Within 10k miles I had done water pump, thermostat, housing, viscous fan (even though it had a water pump - I do suspect many of the aftermarket brands are offshoring production so they nitvalstkng as long as used to when made in Germany..)

I ended up doing it all but one thing at a time. Should have just done it all at once but it was daily driver then so just did it piecemeal.

the parts are not that much money anymore so we’ll worth getting it all done at onceexperience.

I’ve deleted the fan and ran like that for years with just the aircon fan (fitted a fresh one of those though). When I started to use it on track it needed the additional fan so had an electric one put in.

if you are just road use it’s probably fine but do check the viscous for operation- if you have an aircon, the aircon fan kicks in to cool if the viscous can’t cope/is dead.

 

[Dunkelgrun]

Sounds just like mine when I bought it - similar miles when I bought mine 11yrs ago.

Within 10k miles I had done water pump, thermostat, housing, viscous fan (even though it had a water pump - I do suspect many of the aftermarket brands are offshoring production so they nitvalstkng as long as used to when made in Germany..)

I ended up doing it all but one thing at a time. Should have just done it all at once but it was daily driver then so just did it piecemeal.

the parts are not that much money anymore so we’ll worth getting it all done at onceexperience.

I’ve deleted the fan and ran like that for years with just the aircon fan (fitted a fresh one of those though). When I started to use it on track it needed the additional fan so had an electric one put in.

if you are just road use it’s probably fine but do check the viscous for operation- if you have an aircon, the aircon fan kicks in to cool if the viscous can’t cope/is dead.

Thanks, yes, my z has aircon that still works well on the few summer days that I need it. Drove it 4 hrs. in 90+ degree Fahrenheit last summer with no issues whatsoever. I don’t track it at all, just enjoy driving it easy on the back roads mostly

 

[Ianmc]

My experience of four Z3s, two E36s and an E30 is that OEM radiators last for 20 years, give or take a year or so. They often let go at the most inopportune time I find!!!

 

[Dunkelgrun]

My experience of four Z3s, two E36s and an E30 is that OEM radiators last for 20 years, give or take a year or so. They often let go at the most inopportune time I find!!!

Sounds like mine might be on borrowed time then

 

[Dino D]

My experience of four Z3s, two E36s and an E30 is that OEM radiators last for 20 years, give or take a year or so. They often let go at the most inopportune time I find!!!

Agree. Mine lasted 20yrs and was a bit bowed for the last 5 or so I think.
It even survived the viscous fan shedding some blades and suffered only superficial damage from that.
I changed it as preventative maintenance (only to have the newly refitted viscous take out the new rad but that was on track - so now I run an electric fan in its place. Track use shows up things even hard road driving does not so not a good barometer unless you tracking it).

the radiators are pretty cheap nowadays too but some look suspiciously cheap!

 

[AirOps]

I did a complete cooling system refresh last fall before taking the car to Florida for the winter. Previous experience has taught me to do as much as possible in a single go to avoid having a weak link in the system and having to duplicate work. I accumulate all of the necessary parts prior to beginning the job to avoid having to source parts during the job. Mine had 115,000 miles and at some point had some cooling system work done, water pump, thermostat & housing (Aluminum vs O.E. plastic), both radiator hoses (aftermarket not O.E.), and I think the radiator? Since I planned to be away for several months and did not want to have work on the car while on the road I did a max refresh of the system (all hoses, radiator, water pump, thermostat, and a electric cooling fan), as well as several other components which were easier to access during the job. I am now back home and can say that the car performed without a single problem over the 6,000 miles on the road.

 

[Althulas]

Nothing like a bit of preemptive maintenance.