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E30 (1982 - 1993)
God's Chariot. The E30 was produced primarily from 1982 through 1991. The cabriolet was the one exception which was produced through 1993.

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  #1  
Old 07-17-2013, 04:13 PM
mississippster mississippster is offline
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Location: Long Beach, MS
 
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Mein Auto: 1988 BMW 325is
Engine roar diagnostics

Hi folks!

I am new to the BMW world and am not disappointed in the least. I have recently acquired a 1988 BMW 325is (e30), and she's a beauty.

However, I have recently started to hear a loud engine roar that grows louder with acceleration. I have noticed a significant decrease in MPGs since the start of the noise. The kicker is that when I was driving on the highway about an hour in, the noise stopped and the mpg gage showed a 3-4 mpg increase. Shortly after the noise stopped, it resumed once more with the same reduction in mpg. I haven't noticed any reduction in power, though I have yet to push her hard in order to tell. The engine roar is smooth and not high pitched. Sounds as if it is coming from under the hood.

Any advice would be greatly appreciated! Thanks!
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  #2  
Old 07-17-2013, 06:58 PM
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downhiller downhiller is offline
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oh no youve awaken gretchen!

vids would help the best
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  #3  
Old 07-17-2013, 07:58 PM
mississippster mississippster is offline
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Thanks for the response Downhiller! I don't know who Gretchen is? Do I google it? Have any links to videos?
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  #4  
Old 07-18-2013, 08:24 AM
Ken@BavAuto Ken@BavAuto is offline
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Location: Portsmouth, NH
 
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Mein Auto: 1989 325is
Tough to really say what it is without seeing/hearing it in person but have you checked the intake boot from the throttle body to the air flow meter for cracks? It's a common failure part and could potentially "open up" under load with the engine physically moving on it's mounts and seal up somewhat at rest. And intake noise is often described as a roar. How's the car idle? If you do find the boot is cracked we typically keep them in stock but there are a few different ones used for your year. You should know the production date of the car (look in drivers door jamb) and of course what transmission it has to get the right one.
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  #5  
Old 07-18-2013, 01:15 PM
mississippster mississippster is offline
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Ken, the boot is not cracked. It is still in great shape surprisingly enough. The idle is also solid - no fluctuations in the rpms or sputtering. My older brother looked at it said that he thinks the fan clutch is sticking, although I have not had any problems with the car over heating. Have you ever heard of problems associated with the clutch fan other than over heating? Thanks!

Last edited by mississippster; 07-18-2013 at 01:16 PM.
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  #6  
Old 07-18-2013, 01:24 PM
Ken@BavAuto Ken@BavAuto is offline
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If the fan clutch is engaged all the time it would make a bit of a roaring/whoosh noise too. And it would make the car run cooler, not hotter. But a fan clutch that doesn't disengage can sometimes cause the plastic fan to explode which isn't pretty. The fan clutch should lock up and draw air through the radiator when the car is hot, but once the temperature comes down they freewheel to take the load off the engine. So decreased gas mileage and a lot of noise underhood could be a locked fan clutch. We stock Behr fan clutches for $59.95 and Sachs for $64.95. Both are excellent. I recently put a Behr in my 89 to replace the original. They do require a special 32mm thin wrench to install and maybe a pulley holder. It's reverse threaded too. We sell the wrench for $18.95 and the pulley holder for $21.95.
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  #7  
Old 07-18-2013, 09:23 PM
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downhiller downhiller is offline
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Quote:
Originally Posted by mississippster View Post
Thanks for the response Downhiller! I don't know who Gretchen is? Do I google it? Have any links to videos?
gretchen is just an evil german lady you dont piss off. i forgot the movie i saw her in.
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  #8  
Old 07-22-2013, 07:02 AM
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Nick323 Nick323 is offline
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Red face

I saw another movie with Gretchen called
Quote:
3 Schwedinnen in Oberbeyern
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  #9  
Old 07-22-2013, 07:05 AM
mississippster mississippster is offline
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Though I am appreciative of the film suggestions, I'm not quite sure if that is going to solve my engine problem, haha!
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  #10  
Old 07-23-2013, 07:11 PM
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downhiller downhiller is offline
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were tryin to. but we havnt gotten a vid yet
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