I purchased my MCS last year and, as expected, during hot days or when I was into the revs a little just prior to shutting it down the cooling fan would run after shutting it off. It was very subtle and I had to really listen while in my garage to notice it was running at all.

Since the weather turned warm this year, however, that fan has been super loud. Then I noticed a big difference by alternating a single thing; AC on or not.

When I run with the windows down, which is most times, the fan typically doesn't run after shutting down the engine. However, if I was running the AC, then the fan resorts back to the super-loud status.

I tested and the AC is fully charged (and blows cold air).

I tried searching around the forums and did see something in the 1st gen about the power steering fan, but didn't see anything regarding 2nd gen.

Engine coolant level is good, so I can rule that out entirely.

I realize it could still be the AC compressor even with it blowing cool air, but [1] I would have figured on complete failure by now (nearly 2 months after first noticing this louder fan) & [2] the AC compressor wouldn't have a way to make noise with the engine off.

I'm just looking for other suggestions or how to test whether it's the PS fan or the main fan. Or, for that matter, anything I may have missed regarding the AC compressor.

While I'll be poking at it this weekend, I certainly appreciate any other suggestions on what to look for.

 

My fan has been seemingly louder since it warmed up. If you tested the ac, it's fully charged and blows cold air,it could be your noticing it more now. I'm not sure, but maybe the fan has two speeds.

 

Both of my R56's have exhibited similar behavior after moderate to hard driving in warmer weather - I always chalked it up to the fact that there is just a lot of heat under the hood of these cars, and they tend to run hot.

Out of curiosity, have you removed the honeycomb "grill" from your hood scoop, or do you run with it closed off?

 

The cooling fan has two speeds, high and low. You are hearing the fan run at high speed. Whether the fan is off, low or high is triggered by a combination of conditions including coolant temperature and level of pressure in the AC system. If you open the hood after you turn off the engine, you can see and hear the fan running at the different speeds.

 

I looked it over and I can't see anything wrong. Though, of course, it is hard to see too much in such a cramped space.

I replaced the stock "grill" from the scoop with this MiniFini piece. It seemed loud before that was purchased and hasn't changed since I put it in.

I had read about it having two speeds. It's just SO loud this year compared to last year even though the driving style and general weather conditions are the same.

I guess I'll just have to keep an eye and ear on it to make sure nothing bad develops.

 

+1 on RKW " The cooling fan has two speeds, high and low. "

Yep in the summer time after a hard run the high speed will kick on. Or running the a/c for a while, It will run after a short time and shut off.

What you have to watch is when the high speed fan kicks on and run longs when it cold or the car is cold , that mean the coolant might be low and the thermostat is leaking.

 

It's normal and the fan has two speeds, low and very high. I have been hearing it much louder lately with the hot weather in California, my underhood temps have been 140F. Also consider not just the warmer weather but also the humidity levels, high humidity cools the engine a lot better than low humidity dry weather. Intake temps sore when it's a dry heat!

 

It means that high speed is being triggered now, where it wasn't previously. For whatever reason (there are several possibilities), your engine is running hotter now. But you should verify that the noise is indeed coming from the high speed fan. Open the hood and look and listen to the fan. It will be quite obvious if the fan is producing the loud noise.

 

+1 when it runs open the hood, you should hear it pretty easy.

 

I'll try to remember to double check tonight after the ride home. Weather problems in CT last night so I didn't check at that time.

It was just so much louder than last year is what really threw me off. Not just a little louder.

 

Perhaps your hearing has improved.