[Novvaa]

Currently have a 2019 X3 xDrive30i. Will be taking delivery of an X7 soon. My wife and I have talked about keeping the x3 as a second car and driving it until it’s dead. But at 70k miles, we’ve already had a coolant leak (turbo lines, fixed under cpo), Emergency Call System Malfunction (admittedly, this isn’t specific to the x3) and now we have another coolant leak (looks like upper rad hose). So I’m starting to doubt the reliability of the b48.

On the other hand, the B58 is legendary and I’m thinking that maybe we should upgrade the x3 to an m40i and have two B58’s in the household. Would probably cost us 10-15k to upgrade but I’d have a rock solid engine and an x3 that would be MUCH more fun to drive. Would you guys do it?

[ContactPatch]

I would agree that the only thing better than one B58 would be two B58s.

[8ender]

The B48 is basically the same engine minus a few cylinders. Coolant leaks are par for the course with BMWs since I can remember owning them. I think both the 48 and the 58 are extremely good engines, probably on par with the legendary M54 for durability.

[BMWbiker]

If your hypothetical upgrade is $10-15K, then I assume you’d buy used. Then the question becomes: are you taking on someone else’s problem, or not?

That money can instead pay for a bunch of repairs, depending on their scope. Or, a fraction of it could buy an extended warranty, if your current vehicle still qualifies for one.

On the other hand, a newer and zippier car, maybe with additional features, could be subjectively worth it to you. Maybe it’ll be more reliable than your current one. My previous car, an F31, was going strong when a pothole took it out at over 120,000 miles. Little of consequence other than wear parts went wrong with it.

[Burr001]

Originally Posted by Novvaa

So I’m starting to doubt the reliability of the b48.

Just so you understand the problems your having on the 30i is not with the actual engine but the items that may wear over time which is also applicable to any other platform with an engine. But Yes to an M40i!!

[spangle1980]

If you're popping an X7, I'd deffo splash an extra wad of moola to get the M40i

[ASAP]

if you are looking to drive a car until it falls apart... then keep the 30i... if you want a B58 because well a B58 is the best mainstream 6 cylinder turbo (outside of M cars), then get the B58 for obvious reasons

[gphin]

I also have a 19 30i along with a 21 m40. The 30i has been great at 35k...only routine maintenance. Your decision depends on what you want out of your 2nd vehicle. The 40 will obviously be faster and maybe more bells and whistles but will give you a noticeably stiffer ride over your 30i. Have you owned your 30i since new? Assume you would be looking at a used m40? If answer yes, then I would not trade simply because of potential reliability issues. If you're getting an X7 assume that will be your main driver and have your needed bells and whistles. Invest your $15k and use for potential repairs. Can't imagine you would come close to needing that much on future repairs. If you want more performance, put a tune (JB4/Racechip) on your 30i. My Racechip makes a major difference.

[Novvaa]

Originally Posted by gphin

I also have a 19 30i along with a 21 m40. The 30i has been great at 35k...only routine maintenance. Your decision depends on what you want out of your 2nd vehicle. The 40 will obviously be faster and maybe more bells and whistles but will give you a noticeably stiffer ride over your 30i. Have you owned your 30i since new? Assume you would be looking at a used m40? If answer yes, then I would not trade simply because of potential reliability issues. If you're getting an X7 assume that will be your main driver and have your needed bells and whistles. Invest your $15k and use for potential repairs. Can't imagine you would come close to needing that much on future repairs. If you want more performance, put a tune (JB4/Racechip) on your 30i. My Racechip makes a major difference.

Yeah we’ve owned this X3 essentially since new. It was a dealer loaner for the first 3k miles before we got it and it came CPO’d. We’ve done every single maintenance item with BMW. I’ve been reading that I should probably replace the Oil Filter Housing before it cracks and leaves us stranded.

[MFschwifty]

Originally Posted by ContactPatch

I would agree that the only thing better than one B58 would be two B58s.

^This guy gets it haha

On a serious note though, it doesn't sound like you've had any directy engine related problems. If you were burning oil, experiencing poor fuel efficiency that could relate to valve train issues, or noticing lack of power and engine performance then maybe it could be cause for concern.

If you and the wife have been happy so far with 30i with the features that if offers you currently and enjoy the ride why not keep the 10k - 15k set aside for maintenance, repairs and other eventualities as they arise? Vehicle maintenance is unavoidable for wear and tear and with only 70k you should get plenty more life from the vehicle.

If you've grown cumbersome with the available package on the 30i and want to upgrade interior and/or exterior features or maybe just looking for more of a toy as 2nd vehicle rather than a backup to the comfy luxurious X7 then I could see the value in going with the M40i because oh boy is it a blast!

I love my m40i and would vouche for it's ability to put on a smile on your face every time you press that pedal down, even ever so slightly.

Ultimately, just be sure of the reasons why you're upgrading so that way you'll never second guess your decision.

Best of luck with whatever you and the misses choose.

[mcdanielvzw]

Two B58s is definitely nice! We're loving our 2021 M40i's so far (26k and 28k miles). It was more cost than we wanted all at once, but it's worth it at the end of the day.

Edit: I almost always go for lower mile, off-lease vehicles. Much cheaper than brand new and usually the upkeep is on point. Preferably with a little warranty left J.I.C. I need to address something.

[gphin]

Originally Posted by Novvaa

Yeah we’ve owned this X3 essentially since new. It was a dealer loaner for the first 3k miles before we got it and it came CPO’d. We’ve done every single maintenance item with BMW. I’ve been reading that I should probably replace the Oil Filter Housing before it cracks and leaves us stranded.

Here's an article about the B48 that may help your decision regarding potential future and preventive maintenance issues. Good luck either way.

https://bmwinsights.com/bmw-b48-reliability/

[BMWbiker]

Originally Posted by ContactPatch

I would agree that the only thing better than one B58 would be two B58s.

Now I’m picturing in my mind a V12 made of two B58 blocks. Lol. Or is there one like this that I don’t know about?