MtnGn
06-21-2022, 09:21 AM
Just buttoned up the new cooling system on the 540i. Its been sitting in boxes for over a year waiting for me to find time to tackle it: Zionsville radiator/ shroud and Spal two-speed fan installation. The water pump pulley was leaking from a slight unbalancing of the fan clutch and fan. That may have been my doing as I never tightened the fan clutch beyond maybe 14 to 20 ft-lbs because the reverse thread bolt can be a pita to get off. I was on my third OEM plastic radiator anyway, so I took the leap into all-aluminum and electric. I replaced the t-stat with the 88 degree version and remounted the water pump with metal impeller while I was at it.
Overall, it was a straight forward transition. Biggest hurdle was a lack of clear directions... anywhere... on how to install, particularly with respect to the wiring harness. Z-Ville is notoriously useless for customer support. And I kinda understand that. Too many mentally or otherwise mechanically challenged peeps out there asking stoopid questions. I made the wiring harness by hand and there are no right or wrong answers on how to do that bit. But the Z-site has NOTHING on it in that regard. And allot of the links I found on the matter from 10 years ago when the e39 community was larger and this sort of thing was more frequently done... well they were dead. Bottomline, it took time hunting and pecking my way through sparse details and poorly described options to derive my own strategy. It was a good education.
Things I would do differently: I installed the radiator and then built the wiring harness once it was in place. This made it extremely challenging to to drill the fan shroud for various cable management clamps and for mounting fan relays and resistor. I used steel stud material to fabricate mounting elements that I then fastened to the aluminum fan shroud. It did come out well in the end, however if I had known how I would eventually run the harness ahead of time I could have drilled while the fan shroud was out of the car making the task much easier.
The fan shroud came pop-riveted to the radiator btw so its not something you can remove/replace without pulling the entire radiator. Sure, I guess I could have drilled out the rivets and replaced with removable fasteners, but here again that would have taken more forethought. In the end, everything did come together well enough.
I spliced the "coil-leg" of the relays to the ignition wire as has been typically done by others. It works like a charm. However, in retrospect, it would probably be better to wire to another source that doesn't de-energize when the key is turned off. That would allow the fan to continue to run/ cool after the car is parked, only stopping after the thermal switch closes. Though without some testing, this may not be advisable; not sure how long it might take to bring coolant temp below switch threshold. Running the fan for 2 hours after parking would probably not be ideal.
Also, I could have spliced in an over-ride "on" switch under the hood like some others have done but chose not too. Easy enough to revisit in the future if I see a need.
The 10-blade fan is wired as a "puller" and does make noise as others have noted. But its hard to detect when driving. Throw in the radio and its impossible to hear. For me, the pluses outweigh the minuses. The old plastic radiators, prone to sudden catastrophic failure, left me stranded on more than one occasion.
Ask me a question. Happy to respond.
Overall, it was a straight forward transition. Biggest hurdle was a lack of clear directions... anywhere... on how to install, particularly with respect to the wiring harness. Z-Ville is notoriously useless for customer support. And I kinda understand that. Too many mentally or otherwise mechanically challenged peeps out there asking stoopid questions. I made the wiring harness by hand and there are no right or wrong answers on how to do that bit. But the Z-site has NOTHING on it in that regard. And allot of the links I found on the matter from 10 years ago when the e39 community was larger and this sort of thing was more frequently done... well they were dead. Bottomline, it took time hunting and pecking my way through sparse details and poorly described options to derive my own strategy. It was a good education.
Things I would do differently: I installed the radiator and then built the wiring harness once it was in place. This made it extremely challenging to to drill the fan shroud for various cable management clamps and for mounting fan relays and resistor. I used steel stud material to fabricate mounting elements that I then fastened to the aluminum fan shroud. It did come out well in the end, however if I had known how I would eventually run the harness ahead of time I could have drilled while the fan shroud was out of the car making the task much easier.
The fan shroud came pop-riveted to the radiator btw so its not something you can remove/replace without pulling the entire radiator. Sure, I guess I could have drilled out the rivets and replaced with removable fasteners, but here again that would have taken more forethought. In the end, everything did come together well enough.
I spliced the "coil-leg" of the relays to the ignition wire as has been typically done by others. It works like a charm. However, in retrospect, it would probably be better to wire to another source that doesn't de-energize when the key is turned off. That would allow the fan to continue to run/ cool after the car is parked, only stopping after the thermal switch closes. Though without some testing, this may not be advisable; not sure how long it might take to bring coolant temp below switch threshold. Running the fan for 2 hours after parking would probably not be ideal.
Also, I could have spliced in an over-ride "on" switch under the hood like some others have done but chose not too. Easy enough to revisit in the future if I see a need.
The 10-blade fan is wired as a "puller" and does make noise as others have noted. But its hard to detect when driving. Throw in the radio and its impossible to hear. For me, the pluses outweigh the minuses. The old plastic radiators, prone to sudden catastrophic failure, left me stranded on more than one occasion.
Ask me a question. Happy to respond.