Most reliable, easiest to DIY repair

[Razor2014]

Hi,

In the market for a 316i, 318i, 318is, 320i, 323i, 325i or 325e.

Of all the above engines (well I know that the actual engine codes are different but I mean the engines in those model cars above) what would you say is the most reliable and simple to maintain? I know the 316 and 318's don't have the every 15,000 miles valve adjustment to deal with.

I know there are a lot of variables; however, if fuel efficiency, power, speed, etc. were NOT a factor and it was simply reliability, likelihood to go well over 200,000 miles without major issue and simple DIY to maintain what would be the winner.

Thanks for your time.

[Q5Quint]

The m10 4 cyl in the 318 is an indestructible beast with a production run from 62 all the way to 88 or so, if that tells you anything. Timing chain.

The m20 'baby six' cyl variants (320, 325i, 325e etc) are just as good, but had the dreaded timing belt. It isn't actually a problem- just change the thing as soon as you get one. if you don't it might become a problem. Takes about an afternoon to do the belt+ water pump.

The m30 'big six' went from 68 all the way to 88 as well, with a timing chain, if that tells you anything. This was in the 5 series cars but you didnt mention them, so nvm.

Never had a m42 4 cyl from the newer years but a lot of folks like them. Nearly 40 more hp than the m10 of the same size thanks to twin cams and 4 valves per cylinder. Also timing chain.

Reliability and maintenance wise all of these engines can go 300k+ miles IF you change the oil and do basic maintenance. Without hydrolic lifters you will always need to adjust valves... but it takes about 20 minutes so it isnt a big deal.

The issue would be what the previous owner did. I think my 318, the 4 or 5 325is, and the ix I had all had over or near 300k by the time I had them. Their 'reliability' had more to do with what the previous owner did than what I could actually do. A 30 year old ecm can crack during a cold spell and fail no matter how much preventative maintenance you do to the car. A 30 year old ground strap can look fine but when you test it you will see it is not making a good connection, which is what burned your alternator out.

The nice things about the 325 m20b25 engine is that I have had so many, I know what is probably wrong if something is up. No fuel? Your 30 year old fuel pump relay may have just got stuck.

Simple reliability: all of them will be equally just as great or just as horrible as any 30 year old car can be, depending on if their previous owners took care of them.

A quick glance under the valve cover to see how coked up the inside is will let you know what kind of life they lived before. Nice and clean? Your rings and bearings are probably still fine. Toxic sludge from the Jurassic period? Your rings and bearings may be cooked, too, along with everything else in the car that was supposed to get fluid changes.

If we are expecting a 30 year old car with potentially 300k miles to go another 200k miles... then preventive maintenance may include a bottom end rebuild and engine seals freshen up. After that any of these engine will easily go another 200-300k, as the illustrate every day. The rest of the car usually will fall apart before the engine will. Blower motors are getting more and more expensive.

[Razor2014]

Thank you so much for your reply, great information!