Differences between gas and diesel?
 

I admit to not knowing much at all about diesels so here's my question:

My wife has a 2009 X5 with the gas 3.0. We want a new 2015 X5 with diesel due to the increase in MPG. We've never owned a diesel before so I have some basic questions. 1) does it take the same oil/filter as the equivalent gas model? Same for coolant/water pump/thermostat? Is the only difference (maintenance wise) that the diesel has no spark plugs, but glow plugs that need to be changed and obviously the gas is different. Is there more maintenance required for the diesel, ie, fuel pump, filter?
Also, is there a safety in the filler to prevent the use of regular gas?
Sorry for the many questions.

There are far fewer differences than there used to be.

The gas isn't different, the fuel is different. Fuel pump nozzles are different sizes.

No spark plugs, but some additional items, I'd call it a wash on maintenance costs. Owners have reported more frequent oil changes on the diesel models as called for by the condition based monitoring system; that is likely due to contamination of the oil with combustion byproducts. The diesel uses a different spec engine oil than the gasoline model. The component parts may be different due to the different engine model, but they are similar in concept. If you want to check specific part numbers go to realoem.com and look up the two models. The prices shown won't be exact, but they will be indicative.

Diesels can be more sensitive to water in the fuel; with clean fuel it may never be a problem but if you get a tank of bad diesel fuel every now and then you will be doing fuel filters more often than with a gasoline model.

Early X5 diesel models had some issues with the pollution control system (DEF), mainly due to first adopter issues. Seems more reliable now. Similar issues that gasoline engines had when they got new and more complex pollution controls years ago.

Before you jump, recommend you do a basic cost analysis on diesel fuel in your area. The better mileage is an obvious plus. However, depending on the price of diesel you may not see any savings. When I have analyzed it, it has taken in the order of 80,000 km to 100,000 km to break even, because we have more expensive diesel fuel than some areas. Diesel is the same as #2 heating oil, so is subject to seasonal price fluctuations when it is furnace season. For resale, diesels are not trading at any higher price here compared to 35i models, so the original purchasers took a hit on depreciation (the 35d was a $4500 option). If diesel fuel is not relatively expensive where you live, and you can get a vehicle priced similar to a 35i, it can make a lot of sense.

+1 what JCL said,

However in addition to the questions you asked why not go drive one several times to see if the driving experience is any different.?

Thanks JCL. In my area diesel goes for abou $3.85 while super runs about $4.10. Since BMW recommends a minimum of 91, the fuel price is a bonus along with the mileage. When you say water in the fuel and filter replacements, are the filters easier to change since it might be done more often? Also, I've been using Mobil 1 0w-40 for my wife's current X5. Can I still use the same oil (when the warranty expires)? If there's water in the tank, is it ok to put a few bottles of gas dryer (that yellow bottle stuff) or will that harm diesel?

Also, are glow plugs a regular maintenance item, if so how often?

I have read that glow plugs are a 50,000 mile item but can't guarantee that. Call it the same as spark plugs.

If your diesel is cheaper than gasoline that's great. Is that the summer or winter price?

Changing filters is the same as the gasoline version.

You need an LL-04 oil.

If you are leaving the vehicle stored you can use special diesel fuel stabilizers in the tank.

Don't overthink it.

An interesting Thread on gas vs diesel, from the auto section on City Data Forum...

Some of the posts, esp later in thread, are the usual arm wrestles, but there are some very thoughtful opin posts with pros & cons, need for, rationale, etc, imo.

No dog in this fight, but Bill K may find the opins in this thread food for thought.
GL, mD

The more I read about Diesels... - Automotive -Sports cars, sedans, coupes, SUVs, trucks, motorcycles, tickets, dealers, repairs, gasoline, drivers... - City-Data Forum

Looked at the City Data Forum... and IMO it still boils down what someone wants to drive.
Prius vs VW vs Audi. One thing I can agree with is who want's to drive a boring Prius or a another 2 cylinder egg beater just to save fuel. I want a driving experience. So please someone tell me is there a difference in the driving experience gas vs Diesel?

I think there is. The diesel revs low, and uses its torque. The gasoline engine (now that it is turbocharged) can also rev low, with lots of torque but not as much as the diesel, but it can also be run up through the rev range.

Some don't mind the diesel engine characteristic at all. I purchase BMWs partly for the sensation of running a straight six engine up to (less than) redline regularly. I would miss that with a diesel.

I have owned two diesels (not BMW), and they were fine. A bit of a nuisance to refuel, but fine. Good mileage. Just not as engaging as a free revving gasoline engine is.

I tried to make a diesel X5 work in an economic analysis, but couldn't given my local fuel prices. I still like the F15 diesel because it comes with the stronger version of the ZF 8HP transmission than the 35i, but that only matters for heavy towing.

Everyone will have a different version of the above. You've got to drive it and see the difference.

Thanks for all the comments. Honestly, for me I'd probably pass on a diesel. I drive a 95 M3 and an '11 M3 convertible. This is for my wife who finds the bells and whistles entertaining. Going from a regular gas 3.0 to a twin turbo diesel will definitely be a thrill from 0-60 and certainly a noticeable improvement. Currently, she does about 80%highway driving and averages about 22mpg. Diesel is about 10-20 cents cheaper around here so the savings should add up. I was also always told that a Diesel engine would outlast a gas engine. We typically like to keep cars a long time so she understands this will have to last her at least 10 years till the next car.
To add, we just got back from a European vacation and found that gas over there runs about $10/ gallon. It seemed most people drive a car with a tiny engine (I think I actually saw a bmw 516....a 1.6 liter 5 series?) or a diesel. This presidents mentioned before that we should be paying the same as Europeans for gas, and it appears that we're being styled more and more so like Europe so preparations for future high gas prices seems logical.

I forgot to add that her commute is about 90 miles round trip and we take her car for any significant road trips. So the car will get lots of miles racked up. The extra MPG attained would quickly add up. I think the extra cost for the diesel was only about $2500

BMW six cylinder diesels are pretty robust, in my experience. I get 33mpg (imperial) from my E53, but would advocate oil and filter changes mid-way between the service indicators.
My old 525 E39 turbo diesel ran to 204,000 before being sold, it needed glow plugs at 160,000 miles.
The choice of diesel here in the UK is purely economic: more than 12,000 miles each year makes the extra outlay worth it. While my E53 can be entertaining, for fun I take the M3 or Z4.

OP in your ncknof the woods the stop and go traffic will b killer mpg wise if u go with a diesel. I recently traded my 2012 x5d base model for a 2015 x5d. If u do a lot of long road trips further down south or out west, the diesel would be the better option. On recent trips from NYC to FL I saw 33mpg once I got thru DC area. That was at 75mph with cruise control engaged. Letting the x5 think for itself, I feel is key for optimal mpg. On the way back to NYC I ran it at 85mpg w/o cruise control and saw 30mpg which is still respectable for a 5000lb vehicle. I put just under 40k on the 2012 and owned it out right for just over 2yrs. I ordered the 2015 with M pkg, driver assist pkg, convienence pkg and upgraded to be 20" wheels and multi contoured seats. I'm happy with it so far. I have 5k on it. What I liked about the '12 was its styling and the brakes. I'm not into tech stuff so the iDrive system doesn't do anything for me. What I didn't like on the '12 was the drive by wire system. I'd have to keep it in sport mode when starting in traffic. Felt like there was a slight delay when applying the throttle. Sport mode minimized the jump in torque. The '15 brakes r smaller and the throttle delay is still there but it's not as harsh. Once in sport mode you don't feel it like in the '12. All of the 12s short comings are eliminated in the '15 too. Larger NAV screen is nice too. If your into music do t go with the stock system. I could t justify paying 4,500 for the Bang&Olfsan system but wish I did lol. As far as maintenance I only had to go I for urea top off. Sercive intervals were the same as the gas motors. All in all the 15 is a nice looking and very comfortable vehicle. I prefer the e70 looks over the 15 but it's everything the e70 isn't.

Just picture me fueling up the Peugoet 504 D in the mid 70's. It was during the fuel crisis. When I did use a gas station
I made a lot of people mad driving up to the diesel pump until they found out the pump I was using was diesel.
I also knew where all the truck stops were. Now days Diesel Is everywhere. :thumbup: