[paul386]

I have had my X3 for about 3 weeks now. I have a few questions...

The engine coolant temperature seems very high... it runs just under the 250 degree tick on the gauge. Are other people experiencing this same temperature?

Sometimes when I start the car it goes through a series of dramatic RPM oscillation... As much as +/- 500RPM. It normally lasts for about 10 oscillations and then stabilizes at a normal RPM.

On the highway I am seeing low 20's for the MPG. This is at speeds from 70-75MPH on flat highways in Florida. I was hoping for higher MPG. What are other people getting?

[bekind]

While I don't drive our X3 much, as it is the wife's, I was in the garage recently when she started it and had the oscillations. RPMs bounced all over the place for a few seconds. All I could think was great, 600 miles in and need a new HPFP already. I asked her to tell me if it happens again.

Concerning the MPG I think you should see some improvement as the drivetrain and motor get broken in. You'll see your best MPG probably between 55 and 65 mph. As you increase speed the drag increases greatly.

[sfax]

Originally Posted by paul386

I have had my X3 for about 3 weeks now. I have a few questions...

The engine coolant temperature seems very high... it runs just under the 250 degree tick on the gauge. Are other people experiencing this same temperature?

Sometimes when I start the car it goes through a series of dramatic RPM oscillation... As much as +/- 500RPM. It normally lasts for about 10 oscillations and then stabilizes at a normal RPM.

On the highway I am seeing low 20's for the MPG. This is at speeds from 70-75MPH on flat highways in Florida. I was hoping for higher MPG. What are other people getting?

Whole thread on mpg here

http://x3.xbimmers.com/forums/showthread.php?t=489243

[xDrive35i]

Originally Posted by paul386

I have had my X3 for about 3 weeks now. I have a few questions...

The engine coolant temperature seems very high... it runs just under the 250 degree tick on the gauge. Are other people experiencing this same temperature?

Sometimes when I start the car it goes through a series of dramatic RPM oscillation... As much as +/- 500RPM. It normally lasts for about 10 oscillations and then stabilizes at a normal RPM.

On the highway I am seeing low 20's for the MPG. This is at speeds from 70-75MPH on flat highways in Florida. I was hoping for higher MPG. What are other people getting?

I experience the same pulsating variation for the first 25 seconds after starting the engine cold. It's getting better, but it is annoying.

[xDrive35i]

Originally Posted by bekind

While I don't drive our X3 much, as it is the wife's, I was in the garage recently when she started it and had the oscillations. RPMs bounced all over the place for a few seconds. All I could think was great, 600 miles in and need a new HPFP already. I asked her to tell me if it happens again.

Concerning the MPG I think you should see some improvement as the drivetrain and motor get broken in. You'll see your best MPG probably between 55 and 65 mph. As you increase speed the drag increases greatly.

It's not the HPFP. The HPFP recall was on the N54, this is the N55. As well, the HPFP problem was characteristic of spontaneous power loss with consistent engine vibration often confused with engine misfiring. The aforementioned fluctuation is not the same vibration. My service advisor at the local dealership told me that the problem will probably be resolved with a software update; I don't want to believe him, but I can't see how he could be wrong.

I can assure you, to the best of my knowledge, that it isn't the HPFP because the N55 has one turbo and one fuel pump, not two. As well, this engine surging can't be the fuel pump issue because the high power fuel pump would be injecting more fuel, causing flooding, which would make the engine sputter, not surge.

[Razel]

Originally Posted by paul386

The engine coolant temperature seems very high... it runs just under the 250 degree tick on the gauge. Are other people experiencing this same temperature?

You may not realize that the gauge is oil temperature, not coolant. Oil will be at a higher temperature than coolant.

[paul386]

Thanks for the replies guys! All useful information!

[LEDZEP]

Originally Posted by Razel

You may not realize that the gauge is oil temperature, not coolant. Oil will be at a higher temperature than coolant.

Correct, the temp gauge is oil.

As for mileage, there are so many variables. Check your tire pressure. Pushing flat tires down the road will kill your mileage. Has it been windy and stormy? Driving into a head wind is like driving 120 MPH.... will also kill your mileage. People love to try and compare mileage, but they usually don't provide enough details about driving conditions to make the comparisons meaningful. For example, you and I might have similar conditions, tire inflation, etc. but if everytime I pass another car I floor it - and you simply pass them at normal speed, you'll get much better MPG... etc.

[xDrive35i]

Originally Posted by LEDZEP

Correct, the temp gauge is oil.

As for mileage, there are so many variables. Check your tire pressure. Pushing flat tires down the road will kill your mileage. Has it been windy and stormy? Driving into a head wind is like driving 120 MPH.... will also kill your mileage. People love to try and compare mileage, but they usually don't provide enough details about driving conditions to make the comparisons meaningful. For example, you and I might have similar conditions, tire inflation, etc. but if everytime I pass another car I floor it - and you simply pass them at normal speed, you'll get much better MPG... etc.

Exactly. Like, I live in a busy city and drive with a lead foot. I drive only about 11,000 mi/yr. I get an embarrassingly wasteful 11.9 mpg. Fucking cabs get me over excited at the stop lights.

Anyways, I don't know where you live, but from all the people who've posted their mileage ratings, I've not yet found someone who gets worse mileage than me in an X3 35i. The average seems to be around 17 mpg. I would KILL for that. Ah well.