Lost Fan Blades

gdlabola · 08-05-2006, 12:12 PM

I own a 97 328i Cabrio that is having a fan problem. One week ago I replaced my fan (all but three blades remained) and the clutch (thinking the clutch caused the loss of blades). The replacement fan began to get hung up, on the shroud so my mechanic clipped the corners and told me it would be fine (He thought I got the wrong size fan). Today I noticed that three blades are missing again!! I'm thinking motor mounts now.

How does one check motor mounts? Can bad ones cause broken fan blades? Are they hard to replace?

Wayne 962 · Wayne 962's Garage

Hi there and welcome! An odd problem indeed. You can check for bad motor mounts by gently raising the car up by the bottom of the engine block where it meets the transmission. If the drivetrain moves without the chassis following, then it's a motor mount issue.

Seems like an odd problem, can you post some pics?

-Wayne

BMWCowboy · 08-06-2006, 08:45 AM

Has the car been wrecked???-->Check your radiator hold down clips & make sure its not hitting fan

gdlabola · 08-06-2006, 12:30 PM

I've owned the car about two years now. The radiator, water pump, therm housing was replaced about a year ago. To my knowlege the car has never been in a wreck. All of a sudden I keep loosing fan blades. When I installed the last one is spun freely and did not hit anything until several days later my noticed a clicking sound. when I checked the fan was stuck in the shroud.

BMWCowboy · 08-06-2006, 02:15 PM

make sure the shroud is installed correctly & tighten the fan,
have seen some that had been installed incorrecly & they warped into the new position-->so had to put new shroud on

gdlabola · 08-07-2006, 03:17 PM

I just climbed out from under with my jack. The motor mounts check out OK using Wayne's method. What's next? I really am stumped!

Wayne 962 · Wayne 962's Garage

I would guess that the shroud is not properly installed, or the radiator itself is missing the proper mounts at the bottom, causing the shroud to flop around. Remember, the fan is attached to the engine, the shroud attached to the chassis / radiator, so if the radiator is not tightened down properly, you may have this problem. Check the plastic retaining clips for the radiator too...

-Wayne

Jeron · Jeron's Garage

Can you see where the blades are hitting something? My guess would be it is hitting the radiator.

Wayne 962 · Wayne 962's Garage

Quote:

Originally posted by Jeron
Can you see where the blades are hitting something? My guess would be it is hitting the radiator.

Right, there must be some tell-tale signs of destruction!

Pics please!

-Wayne

gdlabola · 08-11-2006, 07:22 AM

I think I have this figured out. The fan has struck the shroud as evidenced by some scrapes on the inside of the shroud. Something is moving.

I originally thought it was the motor but after the motor mounts checked out this was ruled out.

That leaves the radiator. I can move it from side to side approximately 1/2 inch. It must be shifting under hard cornering and hit and break the fan. I think that when my radiator was replaced last year the lower grommets stuck to the old radiator and are missing.

I've ordered a bunch of stuff from Pelican and hope to get into it this weekend. I'll let everyone know what I find

Wayne 962 · Wayne 962's Garage

I wouldn't really call them grommets as I would call them mounts. They are about 1.5" in diameter, and are like 1/2 of a raquet ball. True - if they are not in there, then you will have some serious movement!

-Wayne

gdlabola · 08-21-2006, 04:38 PM

I finally got into it last weekend. Replaced the upper and lower radiator mounts, fan and shroud. The radiator doesn't move anymore and after a week I still have all my blades. I think that the upper mounts became loose and allowed the radiator to shift and the shroud hit the fan.

Thanks to all for your suggestions.

Tahirh121 · 09-05-2006, 03:16 PM

Dude i had the same problem about a year ago...exactly the same symptoms and issues.
I went through three fans before i figured out what it was.....and that was by accident.

The reason mines broke was because the the water pump in my engine was the one with plastic impellers. These break down after time and will eventually give way causing issues with over heating etc.
In my case, the only time my blades broke was when i accelarted really hard off the mark... this caused the pump to spin fast and jam because of the impeller bits that were breaking off....in turn shunting the blades and putting them out of balance therefore possibly hitting the radiator plastic lining or cover.
Either way a combination of the above caused the problem.
After replacing the water pump .... I have not had any baldes breaking...

hope that helps.

Wayne 962 · Wayne 962's Garage

Some of the new water pump impellers are still plastic, but they are now a composite plastic that supposedly won't break down...

-Wayne