A bit vague, but here goes. Assuming an E46 vs E39 or early E60, the six
cylinder engines (M54) are identical. You can expect similar reliability in
both 2.5 and 3.0 liter models. The newer E90 and 2006 E60 has a new engine
with a magnesium block (its encapsulated in aluminum). Very high tech, very
powerful for 3 liters (the 325 and 525 are now a somewhat simplified
variation of the same engine, now 3 liters), too new to say much about
The E39s and E60s also have a V-8 available. Different animal. A lot more
grunt and somewhat less refined in the handling department. The earlier E39
V-8 tended to overstress the cooling system (radiator failures in the
60-75000 mile range not uncommon) and had an oil pump bolt issue (now
resolved). The new V-8 in the E60 is a technical marvel, probably too early
to comment on reliability. Generally, BMW I-6's are more reliable and more
maintainable than the V-8's.
I think its more critical to address what you want in a car. The 3's are
more sporting, the 5's more luxurious. But a 5 with sport package is more
sporting than a 3 without. And a 3 with performance package .... Well you
get the drift. Drive both cars and decide which one better meets your needs
and desires. The powerplant shouldn't be your primary concern.
R / John
Generally speaking the smaller the body and larger the engine the less
stressed it will be in operation. In particular the final drive ratio is
higher with larger engined models so: -
lighter body - less effort to achieve same acceleration / speed
larger engine - less rev's to achieve same power / torque
higher gearing / final drive - less rev's to cruise at same speed (look for
mph / 1,000rpm)
obviously an engine that spends most of its time doing lower rev's will last
longer than one that is constantly thrashed near to its maximum rev's /
You need to be more specific. Some engines are shared between models - but
there are frequent engine updates so even if both cars are approx the same
age and nominally the same capacity, it doesn't mean they have identical
*Letting a cat out of the bag is easier than putting it back in *
Dave Plowman email@example.com London SW
Well, a 525 and a 325 are the same engine. The 4 series does have a wider
range of engine choices, and offers engines that are not found on the 3
Series. But, if the las two digits are the same, odds are very good that the
engines are the same.
Although the poster probably meant 5, not 4, BMW was originally planning to
label the E90 (E92) coupes & convertibles as a "4" series. IIRC, the Z4 was
named during this period.
If the (not for U.S.) 1 series 2 doors were also called a "2" series as
planned, then BMW would have all series from 1 thru 7 covered. Luckily,
saner heads prevailed and we now have a detuned 3 litre engine badged as a
325, and 525, but as a Z4 3.0!
Read about that. Evidently the cost of just changing the 3 series coupe to
"4 series" is substantial and BMW changed their minds.
R / John
Well, the 323 was a 2.5, but they wanted a bit more differentiation from the
328, ergo 323. And the 540 was a 4.4, and so on and so on.
There's a significant mechanical difference between the "25" and the "30"
even though the displacement is the same. The 3 liter in the 330i has
SERIOUS grunt and I suspect is at least the equal of the majority of 3.5's
the Japanese are currently marketing.
R / John
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