Broken Fan Blades Causing Engine Shake?

**Mendo** · 09-25-2011, 06:46 PM

Sorry for the super newb question but I just bought this 96' 328i convertible the other day. I took off onto the highway and shifted at about 5-6k rpms. When I got to the stop light the whole motor was shaking pretty bad. My check engine light had come on the day before but it was still running great so I thought something must be wrong with the motor that was causing this shake.

I scanned it and got a 1421 code which is the Secondary Air System Bank 1.

As I was checking out the motor I noticed that 3 fan blades were completely broken off! The fan shrouds middle tab on the radiator had come loose and the shroud was sticking towards the engine very slightly now. I looked on the inside of the shroud and you could see where there was contact with the blades. I did not hear anything break and there was no other damage which seems odd as if 3 blades broke while at very high rpms it seems they would of gouged the radiator and reaked havok on alot of other parts when they flew off.

My theory is when I shifted the motor torqued so much that the blades hit the shroud and broke.

My question is, is the missing blades on the fan causing my motor to shake or something else? I am going to order a new fan asap but this is my only car is it safe to drive it with the missing blades and shakey motor for now? Thanks!!

**Go3Go** · 09-25-2011, 07:04 PM

Broken fan blades will definitely cause the engine to shake because the fan is now off balance. As for the check engine, I'm pretty sure that's just for an air pump that helps with emissions for the first 30 seconds or so the car is on after a cold start. You should be able to clear the code and just let the car warm up for a minute or so for every cold start to keep it from coming back on. (someone please correct me if I'm wrong here though)

**flyfishvt** · 09-25-2011, 07:25 PM

There are several causes for broken fan blades. Bad motor mounts, loose fan shroud, faulty water pump and just plain old everyday age.

You should have the motor mounts checked. The water pump you can do yourself. Just take off the serpentine belt and grab the fan and try to wiggle it. If there is ANY play in it then get it replaced.

You need to get that fan and clutch off asap. Its off balance and the other blades will certainly break off. You got lucky with the first three blades. You luck probably wont continue with the rest of them. You can drive the car without the fan. Just run it with the AC on all the time till you get a new shroud and fan blade. With the AC on your auxilliary fan will keep the car from overheating when you aren't moving very fast or standing still.

don't bother replacing the fan blade if you aren't going to replace the shroud. Its a disaster waiting to happen.

Nice car. I like that color blue with a tan interior. You don't see a ton of e36's with that color exterior.

Welcome to the club.

**Mendo** · 09-25-2011, 08:54 PM

Thanks for the replies. I just took off the fan (what a pain there is NO space) and it runs PERFECT now. So ya that was defiantly the cause of the shake. Is it ok to leave the clutch on there or does that need to come off to while I wait for the new fan? I dont have the right tool to take off the nut so would like to avoid taking it off if its safe. Thanks again!

Chris

**flyfishvt** · 09-25-2011, 08:59 PM

I would take it off only because its much easier to install the new fan blade. I took some vise grips with narrow teeth and lightly clamped onto that nut. Then give the vise grips a good sharp wrap with a hammer. If you hit it good and solid it should break free and spin right off. Just remember its a reverse thread. Righty loosy, lefty tighty.

**Dash01** · 09-26-2011, 11:25 AM

What he said. Using an old toothbrush, put a dab of Antiseize on the threads of the fan and also on the mating threads of the mount, so it will come free readily next time.

You're lucky those blades did not puncture your radiator, but check it for damage or leaks. Better to know now rather than out along the highway somewhere.

Also, check to see if you have a plastic power steering pump pulley, and replace it with a metal one, yesterday. The plastic pulley will grenade, take out both belts, radiator, fan, and cause sudden overheat and possible warped or broken head, all in less than a minute.

This might be the perfect time to do fan delete, so bone up on that topic, as lots of guys have gone that route with no ill effects. My personal preference may run to moving the stock AC aux fan to behind the radiator, using the shroud (with fiberglass reinforcement) to mount it. (AC aux fan still flows front to back, but pulls rather than pushes, and the car is already wired for that.)

**blueberry** · 09-26-2011, 05:28 PM

i have a good condition fan with clutch from my 93 325i for sale if you want it. I did a fan delete mod so i no longer need the fan. selling cheap!

http://forums.bimmerforums.com/forum....php?t=1715760

**VerticalNeptune** · 09-26-2011, 09:53 PM

Dude, two things:
1) You've got to replace those side repeaters with some clears - it just doesn't look right with the originals!
2) Love that picture from the psychotic cameraman who sat on your trunk while you drove through that tunnel

Hope you get your fan sorted/removed !

**fun2drive** · 09-26-2011, 10:05 PM

Be careful as you will beat the bearing out of the water pump in short order so if the pump which by the way is cheap has any play in it at all replace it.
That is the weak link in an otherwise solid car. Water pumps don't last too long 60K miles to 90K miles but if the pump goes you stand a great chance of overheating the engine warping the head.
I had this color before with a sand interior, 328 as well with 5 spd and it was a sweet car even had a hardtop.

**Mendo** · 09-28-2011, 01:59 PM

Blueberry thanks for the offer, I wish I woulda known before i just spent $80 for a new fan blade from pelican

Took me forever just to find a place that would ship to hawaii without charging me international shipping rates. Ive been cruising the bimmer without the fan blade for a couple days now and even in the extreme heat here it hasent gotten hot unless im at a dead stop for a few minutes. Luckily there is almost no traffic on the island so I just keep it movin.

Thanks for the compliments on the car I really like it. Coming from my 750il convertible the 328 feels like its on rails.

**blueberry** · 09-28-2011, 04:51 PM

so just return that one and buy mine.

Thought I would offer. Glad it got taken care of. If it didnt get to like -20 some winters here, I was thinking about an e36 vert as well. Looks clean.