Problem about the speedometer and the engine fan

BB88BB88 · 06-09-2008, 02:08 AM

Hi, I just figured out the speedometer accuracy on my 2007 328i coupe is not acurate. For example, when I am driving at 80km/h, the GPS shows it is 75km/h. The BMW speedometer reads faster than the actual speed. I don't know whether it is normal for BMW or not?
And the other thing is the engine fan is so loud sometimes, especially in the daytime when the weather is hot, but the car is cold start; it is due to the temperature detector problem or the air condition compressor problem or it is normal on the other 3 coupe ?
Thx!

rce90 · 06-09-2008, 02:23 AM

I'd say the loud fan is normal because of your a/c. It needs to draw air through the condenser in order for the refrigerant to change from gas to liquid. No ram air so yea the fan will be loud. As fas as the speedo, i don't know bro.

Peej · 06-09-2008, 03:51 AM

Speedo is perfectly normal

it is some kind of margin that bmw puts in the speedo.

EDK99 · 06-09-2008, 08:52 AM

Most manufactures put some kind of margin so the spedo reads faster then your are going. It is called CYA.

VGR00 · 06-09-2008, 05:35 PM

Speedos are always calibrated to read higher than actual speed. Also don't assume that the GPS reading is accurate either because satalites are constantly moving and wile your car is also moving, the unit is only sampling and displaying an average.

andy92782 · 06-09-2008, 05:57 PM

BMWs always have inaccurate speedometers. They always read too high (VWs are even worse).

FWIW, Japanese and American car speedometers are typically dead-on. It's a German thing.

I335 · 06-09-2008, 08:50 PM

Your fan shouldn't be doing that at cold startup, and it shouldn't be loud for more than, oh, I don't know - 45 seconds maybe? If it's loud for a long time you should have it checked out. At least that's what my 335 fan is doing, even in 95 degree weather.

As for the speedo - normal as everyone says and is not unique to BMW. I'd like it to be dead on but sometimes I think it's a good thing. It would be much worse if it was the other way around...

Sinister Stairs · 06-09-2008, 09:19 PM

What I find funny is that despite the speedo inaccuracy (i.e. a BMW drives slower than the speedo indicates), BMW drivers still get more speeding tickets than other drivers, according to insurance company statistics.

06-09-2008, 02:08 AM	#1
BB88BB88 Registered 0 Rep 2 Posts Drives: BMW 328i Join Date: Jun 2008 Location: Toronto iTrader: (0)	Problem about the speedometer and the engine fan Hi, I just figured out the speedometer accuracy on my 2007 328i coupe is not acurate. For example, when I am driving at 80km/h, the GPS shows it is 75km/h. The BMW speedometer reads faster than the actual speed. I don't know whether it is normal for BMW or not? And the other thing is the engine fan is so loud sometimes, especially in the daytime when the weather is hot, but the car is cold start; it is due to the temperature detector problem or the air condition compressor problem or it is normal on the other 3 coupe ? Thx!
	Appreciate 0 Tweet Quote

06-09-2008, 02:23 AM	#2
rce90 Private 3 Rep 61 Posts Drives: 2008 328i Join Date: May 2008 Location: Rancho Cucamonga iTrader: (0)	I'd say the loud fan is normal because of your a/c. It needs to draw air through the condenser in order for the refrigerant to change from gas to liquid. No ram air so yea the fan will be loud. As fas as the speedo, i don't know bro.
	Appreciate 0 Quote

06-09-2008, 03:51 AM	#3
Peej Private 1 Rep 98 Posts Drives: VW Golf 3 Cab. Join Date: Jan 2008 Location: The Netherlands iTrader: (0)	Speedo is perfectly normal it is some kind of margin that bmw puts in the speedo.
	Appreciate 0 Quote

06-09-2008, 08:52 AM	#4
EDK99 Captain 33 Rep 934 Posts Drives: 07 E85 M Join Date: Jul 2006 Location: FL iTrader: (0)	Most manufactures put some kind of margin so the spedo reads faster then your are going. It is called CYA. __________________ 2007 e85 Imola Red \| Black Leather \| Carbon Leather Trim \| Premium \| Navigation \| Heated Seats
	Appreciate 0 Quote

06-09-2008, 05:35 PM	#5
VGR00 Major 53 Rep 1,497 Posts Drives: 430i Gran Coupe Join Date: Feb 2007 Location: Brisbane - Australia iTrader: (1)	Speedos are always calibrated to read higher than actual speed. Also don't assume that the GPS reading is accurate either because satalites are constantly moving and wile your car is also moving, the unit is only sampling and displaying an average.
	Appreciate 0 Quote

06-09-2008, 05:57 PM	#6
andy92782 Private First Class 7 Rep 164 Posts Drives: '10 C2S, '04 4Runner 4x4 V8 Join Date: Feb 2007 Location: OC, CA iTrader: (0)	BMWs always have inaccurate speedometers. They always read too high (VWs are even worse). FWIW, Japanese and American car speedometers are typically dead-on. It's a German thing.
	Appreciate 0 Quote

06-09-2008, 08:50 PM	#7
I335 Brigadier General 123 Rep 4,249 Posts Drives: '08 335i Coupe Join Date: Jan 2008 Location: New England iTrader: (11)	Your fan shouldn't be doing that at cold startup, and it shouldn't be loud for more than, oh, I don't know - 45 seconds maybe? If it's loud for a long time you should have it checked out. At least that's what my 335 fan is doing, even in 95 degree weather. As for the speedo - normal as everyone says and is not unique to BMW. I'd like it to be dead on but sometimes I think it's a good thing. It would be much worse if it was the other way around...
	Appreciate 0 Quote

06-09-2008, 09:19 PM	#8
Sinister Stairs Private 6 Rep 51 Posts Drives: 07 335xi Sedan Join Date: Apr 2008 Location: Michigan iTrader: (0)	What I find funny is that despite the speedo inaccuracy (i.e. a BMW drives slower than the speedo indicates), BMW drivers still get more speeding tickets than other drivers, according to insurance company statistics.
	Appreciate 0 Quote