I had a dealership replace an alternator in my 06 LR3 HSE, and now the gas mileage has reduced from 14.5 to 12.2 on average.

I'm not expecting great gas mileage, but was curious if this would be expected? I would have thought, if anything, a new alternator would reduce drag and improve gas mileage.

Any thoughts or additional information I can provide?

Thanks!

 

What was the problem with the old alternator? There might be a slim chance that the mode in which your old alternator failed actually improved fuel economy. Not very likely though.

 

How have you determined that your fuel economy went down? From the digital readout or hand calculation? This seems unlikely.

If it's from the readout, I'd suggest resetting it and driving it enough to get a more accurate average.

 

Have you questioned the dealer about the drop?
......

 

Thanks for the replies.

The battery light turned on, and the dealership said it the alternator was testing bad.

Yes, and the service agent didn't have a reason why, and was going to ask the technician, but I haven't heard back.

 

houm_wa, missed your reply, sorry.

Before the change, I had verified the readout with a manual calculation, but I haven't done that post. More difficult to do when it's primary the wife's ride, but I'll do that soon.

Is it easy to reset the readout?

 

Man, I wish MY alternator would fail that way!

 

Yeah just navigate to the MPG readout using the button on the stalk, then hold it down until it blanks. I like to do it at the top of a long downhill where I can idle down and get 999.99 MPG...just for fun.

 

Ha, that's brilliant.

 

I should take a photo and send it into Consumer Reports. They'd $hit their pants!!