jtxc

This morning I noticed a rattling going on, it is cool here, not frigid (yet). Does'nt sound good. After 3 minutes it went away. I usually give it 3-4 minutes before I drive it in cold weather, but with a rattle like this I'll wait longer if I have to. I have a feeling this could be a small problem so I'll investigate again tommorow or tonight and report any findings.

Anyone else with this problem? Maybe 545 specific?

Wiu-Bimmer

When I don't use my car, say for three days, I get this rattle when I initially start the engine, it lasts for about five-ten seconds and then it goes away. It sounds worst and for a longer time if I start the engine with the A/C on, so I try to do it with it off. But as I said, I only get that when I have not used the car for a while.

Flowerfred

It's never a good idea to warm up the engine while stationary. Far better to take of slowly straight away.

jtxc

It's never a good idea to warm up the engine while stationary. Far better to take of slowly straight away.
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I don't get that thinking FF. You would know better than I, so I'm interested in the theory behind this thinking. I always thought a few minutes to let the oil warm up and cycle through the engine was a good idea. You are not the only memeber to post that thought so I'm probably wrong, but I'm the type of person that needs the reasons why.

Wiu-bimmer....I did not drive the car yesterday (just cleaned it and put her up) so that may have some weight, we'll see.

Flowerfred

I thinks the theory is that the machine was made to move, not to stand still.
For example, the greasing of the gearbox works by the bottom bit of a radar(dunno the right term, tandwiel in Dutch, teethed wheel literally translated)
running through the oil and splashing the oil all through the gear box. centrifugal greasing. That only works with the car in motion.
The other thing is that the manual recommends it, even for diesels.

Wiu-Bimmer

Wow!!!,
Thanks FF,
I was not aware of this at all, it was always my understanding that running the engine for say 30secs before engaging the transmission was always better, the reasoning behind it being that more resistance would be put on the engine when shifting to Drive, but then again, I'm no engineer

my530i

Wiu-BMer,
Back in the old days with carburator, cars need to have warm air to mix with fuel to get a good mixture for the intake. Not anymore for computer controlled fuel injector cars. Therefore, just turn on your engine for about 30 secs or so, and start driving slowly to have all moving part such as transmission, differential, axle warming up.

Tim C

I hear a clattering sound on cold start that is in frequency with engine RPM and lasts for a few minutes. The sound reminds me of diesel engine clatter as I hear it from inside the car. I assume it's valve clatter, or injectors?

kscarrol

Can't remember where I read this but I think it was the first Roundel or BMW magazine I got after buying my car. The was a short blurb about this issue and the gist of it was leaving the car idling to warm up the engine takes longer than just driving the car. Since most of excess wear takes place while the engine was cold, the study suggested to just go ahead and drive (no hard driving at first) to get the engine warmed up faster. This was from BMW and not just someones opinion.

John W

Yep, I always heard that without running the engine faster than idle, the oil pump isn't circulating the oil much, so you're not heating it up, the car takes longer to warm up, and you're underlubricating the engine, since colder oil flows more slowly than warm oil. So, by driving easy for the first few minutes, the engine lubricates better and warms up faster. Many manuals tell you not to warm up at idle.