Amsoil quirks...

[ivopivo]

I changed my oil yesterday on my 99 M3 and used Amsoil Euro Car oil 5w40 with Mahle filter. This is what I noticed... my idle is a little lower than before, probably at around 600 as opposed to 700 or so before. Also, clutch seems to shake a bit more when starting the car compared to before, but I only started it a couple times after changing the oil so I don't know how consistent that is. Idle is what's bothering me the most since I don't know why it would be lower when oil is about the same weight...

Quick history... bought car August 2008, changed oil with Mobil 1 0w-40 immediately, then same oil this past April or May roughly 5k later, and now the Amsoil about 6k after the last change.

Car runs fine, no knocking or other weird noises and everything seems fine, but the idle is just bothering me a bit so figured I'd ask as I'm a noob with oil and engine internals in general.

[M3_MadBimmer]

i doubt the oil chnage caused it.

I went from mobile one, to royal purple, to redline to amsoil and amsoil pwns all. It's the only time I can honestly say i've noticed a difference by switching to a different oil. The extreme cold weather start up is stunning with the amsoil. Virtually no knocking/ticking noise on first start up on a -20* day

[ivopivo]

Originally Posted by M3_MadBimmer

i doubt the oil chnage caused it.

I went from mobile one, to royal purple, to redline to amsoil and amsoil pwns all. It's the only time I can honestly say i've noticed a difference by switching to a different oil. The extreme cold weather start up is stunning with the amsoil. Virtually no knocking/ticking noise on first start up on a -20* day

Is it possible for oil to change the idle at all? It's not a big or even significant change, but that is the only thing that could've caused it since it was same as always and all I did was pull the car into the garage, drain oil, fill oil and turned it on. I don't know much at all about engine internals but there's really nothing else that could've changed the idle (again, not significant as it's probably about 100RPM less, but enough to bug me and wonder haha

[M3_MadBimmer]

i dont think so, did you put the valve cover oil cap back on?

[thedude]

Originally Posted by M3_MadBimmer

i dont think so, did you put the valve cover oil cap back on?

Also check that your seals are good. I had a similar situation and turned out the gasket around my dipstick was loose and caused the idle to drop

[ivopivo]

Originally Posted by M3_MadBimmer

i dont think so, did you put the valve cover oil cap back on?

haha man I'm a noob but come on now

Originally Posted by thedude

Also check that your seals are good. I had a similar situation and turned out the gasket around my dipstick was loose and caused the idle to drop

Seals are all good... like I said, it was a simple oil change and nothing else. Oil filter housing is tight, drain plug too, so its the dip stick and cap. Unless there is a bad seal on the cap but I don't see how it went bad from taking off and putting it back on once...

[FIKster]

Run the car without the cap, see if you notice a difference.

Are you sure this is not all in your head? I do that to myself quite often. Just hook up a scan tool, it should tell you what the desired idle speed, and then the actual idle speed. Compare the two, if they are close (like desired: 700 and Actual: 675) then I wouldn't lose sleep over it.

[ivopivo]

Originally Posted by MassterTek.

Run the car without the cap, see if you notice a difference.

Are you sure this is not all in your head? I do that to myself quite often. Just hook up a scan tool, it should tell you what the desired idle speed, and then the actual idle speed. Compare the two, if they are close (like desired: 700 and Actual: 675) then I wouldn't lose sleep over it.

I'm positive it's not in my head, but like I said, it's nothing serious. It's idling smoothly once it warms up for a couple minutes just a little lower than before.

I did hear a little starting noise though, sounds like a rusted wheel turning that I can't figure out wtf it is and that too is after the oil change, but might be coincidental... I know Amsoil is good but I feel like draining it all and putting back in M1 0w40 just to see what happens... too lazy to do it, too much money wasted as well as time... what to do what to do haha

[FIKster]

It makes a rusted wheel turning noise while cranking??? Or during warm up...

[QuickGuy]

I'd let it be. Whatever it is it is very unlikely it is from the oil. Maybe you nudged something changing it?

If you decide to drain the oil can you use a clean pan and call me? I will come pick it up and pour it into my M3

[fretburnr]

did you replace the oil filter housing seals with the new filter? Just wondering, as a mild vacuum leak may occur from there.

[FIKster]

Vacuum leaks would normally increase the idle tho right?

[fretburnr]

Not necessarily. A big monster one will tend to stall the engine, unless the engine management steps in heavily to boost idle. Little ones can go either way - if the computer "corrects" by boosting idle, then it gets raised; otherwise, the extra unmetered air being ingested moves the idle off of stoich mixture and idle drops.

I know what you're saying, though - many cars, idle will dip and then raise when a little vac leak is introduced.

[ivopivo]

Originally Posted by MassterTek.

It makes a rusted wheel turning noise while cranking??? Or during warm up...

Neither... it does it once or twice when the car is just turning on and has just turned on... like a cold start thing.

Didn't nudge anything and didn't touch anything but oil cap, oil drain plug and oil filter housing cap. I replaced all seals available (oil filter housing cap rubber seal, small rubber seal on the long bolt screwing in the filter housing cap and also the metal washer on that same bolt, along with the metal washer on the drain plugs.) Definitely don't have a vac leak as I checked the seals on both the oil cap and dip stick.

I probably will just leave it as is but if the noises continue I'm going to replace it with the old oil (new 0w40 M1) and go from there.