extremely loud fan

cubanlorenzo · #1 10-25-2004, 11:58 AM

I have a 1995 blazer. when the car is started, and the hood is open, and i hit the gas, you better be 10 away from my car, or you will get blown away by the wind from my fan. also you might be deafened as well. extremely loud roar comes from there. i have read other forums and they seem to say that it is the fan clutch. i tried to turn my fan like they said but mine turns with no problems. my mechanic said that he has drove blazers before and they are quite loud but mine was louder then theirs. it sounds like a plane engine when i hit the gas. what do you think???

wolfox · #2 10-25-2004, 01:32 PM

Fan clutch gets my vote - will cost on average about $55+ tax if equipped with A/C. Get the plain old one. Do NOT get a heavy duty replacement, they only work if you have your fan blades pitched more than 2". (A common *gotchya* for folks that think a heavy duty unit will last longer. It just makes even more noise unless you have a fan to match) Even a "stuck" viscous clutch can turn freely by hand, and totally lock up when turning at engine speeds. Getting this swapped out now will boost gas mileage, and save a ton of wear and trear on your water pump bearings. It's a cheap fix and easy to do yourself. Some auto shops that you buy the replacement from will rent you the tool to take the nut off of your fan making the swap easier.

BlazerLT · #3 10-25-2004, 01:41 PM

Fan clutch is gone.

Answer this for me, when you are accelerating on the highway, does the fan die down after you hit 2000+rpms?

cubanlorenzo · #4 10-25-2004, 07:43 PM

not really, it does it when it wants to. sometimes it will stay loud until 3000. i just had to replace my water pump not that long ago.

Mikado14 · #5 10-25-2004, 08:11 PM

A viscuous fan will always lock up after sitting for awhile, say overnite. What happens is that the silicone based oil settles when it sits. Upon startup, the fan will rotate in a locked state due to this, however, the bimetallic coil in the front of the fan will cause the valve inside to let the oil pass into the resevoir and the fan will slow down. As the radiator becomes hotter, the bimetallic coil will allow more oil into the fan from the resevoir causing it to lock up. When it cools down, the bimetallic shrinks and bleeds off oil into the resevoir. This was the Cliff Notes version of operation.

Now, if when you start it in the morning and the fan is locked, this is normal. It should not take much more than a few minutes to stabilize. If it is staying locked for say....more than 5 minutes, you might consider changing it out. If it is longer and the ambient temperature is above,, I think it might be 50 or 60 degrees, then change it.

However, I would go with the GM original. I do know from personal experience with my '93 that there are several variations and my VIN was needed to determine the correct one for my truck.

BlazerLT · #6 10-25-2004, 10:52 PM

Couldn't have said it better myself.

wilfie27 · #7 01-09-2005, 08:50 AM

New post to an old thread.

I think my fan clutch is bad. The fan runs all of the time even when it was 5 degrees F the other week. I have a 26 mi. drive to work and it never got over 120 deg., hence, not much heat. Someone mentioned to me a flex fan as an alternative to a new fan clutch. I think the lighter fan with a little less pitch could give me more hp and better mpg. Just a thought.

Mikado14 · #8 01-09-2005, 09:28 AM

Quote:

Originally Posted by wilfie27

New post to an old thread.

I think my fan clutch is bad. The fan runs all of the time even when it was 5 degrees F the other week. I have a 26 mi. drive to work and it never got over 120 deg., hence, not much heat. Someone mentioned to me a flex fan as an alternative to a new fan clutch. I think the lighter fan with a little less pitch could give me more hp and better mpg. Just a thought.

The HP gain wouldn't be enough to run your push mower. Go with cooling efficiency, stay with the clutch fan.

BlazerLT · #9 01-09-2005, 01:21 PM

Quote:

Originally Posted by Mikado14

The HP gain wouldn't be enough to run your push mower. Go with cooling efficiency, stay with the clutch fan.

Yes, stick with stock and don't listen to the kids making bullshit claims like more horsepower and fuel efficiency. The fan practically shuts off when you are driving.

wolfox · #10 01-10-2005, 10:56 AM

As the name implies, a flex fan flexes under acelleration, making it completely FLAT. Flat fins do not cool when they spin - might as well install a frisbee under your hood. You will find too that a flex fan weighs nearly as much as the stock fan, therefore totally negating any idea of crank HP gained. It's an expensive, snake-oil treatment for a problem that does not exist on our trucks.

BlazerLT · #11 01-10-2005, 10:58 AM

TRuck, the fan clutch can be replaced and all will be good.

wilfie27 · #12 01-13-2005, 09:34 PM

thanks, I was weighing a $60 fan clutch vs. a $30 fan.

BlazerLT · #13 01-14-2005, 01:14 AM

nope, the clutch is the problem.

Fireplug · #14 01-14-2005, 10:08 AM

You Guys ever see a flex fan when you smash the gas pedal to the floor boards. I have and i have seen a lot of them sticking out of the radiator.
Stock fan clutch 60 bucks ver flex fan 30 bucks + radiator 200 bucks other drivabilty and cooling problems in the summer pricless

Fireplug · #15 01-14-2005, 10:09 AM

PS
I have 1966 Chevelle SS I drag race and it does not have or ever will have a flex fan on it.

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