Member
I replaced the entire cooling system, from radiator to water pump and it's all new.
6 months ago after an autocross, with the hood open afterwards and about an hour after it was all done I started the car for one second as I heard scraping and saw the rad shroud had broken at 1 o'clock on the right (passenger) side. I was able to tape the shroud into position and ordered a new shroud and new fan, because 100K miles warranted it.
Yesterday I did another autocross and there were no issues (except for horrible ticking noise, which all i6s seem to have, which went away the next day). I drove it home leisurely (only 3 miles or so) and no problems. I don't know exactly when it happened, but the next morning I see the shroud has broken and heat-bent in the exact same spot as the original and the bottom locating tabs weren't inserted correctly into the bottom (I'm sure they had been before). The temp gauge is and always has been rock-solid in the exact center of the temp gauge no matter what I do (after getting it warm after a few miles)
Is this a thing or is it only me?
I can tape it into position and not interfere with the fan.
Suggestions?
Do I get another shroud or tape/safety wire the current one and call it done?
Member
Motor mounts
Apprentice w/#yrs. exp.
Replace mounts.
Grumpy
BMW CCA Member
Even replacing the mounts may not help. A long time ago I autocrossed MGBs. I had one car that started catching the fan on the radiator and ripping both to shreds. Stickier tires, more power, don't know what was the root cause, but after losing several radiators as a poor college kid, I just removed the mechanical fan and called it fixed. None of my cars have had a mechanical fan since then.
/.randy
Member
Mechanical fans bite.
Member
Glad that my Oct '96 Z3 came without a mechanical fan. The so-called auxiliary electrical fan is my main and only fan.
Our 2006 Scion xB, 2008 Subaru Forester, and 2008 Buick Lucerne have no mechanical fans.
With mechanical fans being so troublesome and unnecessary, I wonder why BMW kept them on other Z3s long after my car.
BMW MOA 696, BMW CCA 1405
Member
Thank you for the responses, but I don't see the connection to motor mounts. The fan never touched the shroud. The shroud broke slightly on the right side of center and a portion (3 inches or so) of the plastic was heat-bent towards the engine. If I had tried to start it, the fan would have hit the bent shroud and not spun at all. There is 0 damage to my fan, no scraping on it whatsoever that I can see. So I'm missing the connection as to why a motor mount would cause this, especially since heat in the one area caused the plastic to melt and bend.
Apprentice w/#yrs. exp.
Pics!
Ralph
Well, I would replace the shroud regardless of the cause, but to me it sounds like the cause is autocrossing, since it only happens when you do that. Obviously something is shifting around putting undue stress on the shroud when you autocross, and that means something is loose or broken. Probably that something is in how the shroud mounts to the radiator or how the radiator mounts to the core support, or how the core support mounts to the unibody. Unless you have already replaced the motor mounts, I would replace them in any event. I'm guessing the car was hit in the front at one time and something is wrong up there. However, if it only happens when you autocross, just don't do that.
Member
Bad motor mounts allow the engine to move an excessive amount under extreme load. Autocross is about as hard on drive line mounts as anything. Lots of on, and off low gear transitions. It's the mounts.
Dan "PbFut" Rose
Member
1) Water pumpOriginally Posted by Henway
2) Fan Clutch
3) Motor Mounts
Those are the 3 possible causes assuming the fan shroud and radiator are correctly seated in their mounts
Member
I taped the piece into the orientation I found it in. It broke and heat-bent into this position hooked down. It didn't touch the fan.
bent radiator shroud.jpg
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