Just seafoamed

[Flametail]

Well I just seafoamed my engine twice. I got the billowing white smoke and whatnot but there is still a problem. My dad noticed the other day that starting around 2500 RPMs and going up the engine sounded like it had a rattle to it. He and one of his friends suspected carbon buildup on the pistons so that's why I did the seafoam...well after running it through, it's still there. any ideas?

BTW, M42, 254K miles, regular oil changes (gonna actually change it Tuesday.

[Flametail]

bump, still curious.

NOTE: It only does it after the engine has warmed up. I do know it cleaned a good bit out because my MPG went from 21-25 or 27.

[nyle]

hmm. what kind of rattle? if you are listening to the engine run with the hood open can you tell what area its coming from? sometimes its stupid easy fixes. i had a rattle last year... turned out it was the metal part the ignition wire bracket not being fastened tightly enough.

[96cali]

how old is your catalytic converter? that would also explain a MPG decrease. have u hooked it up to a scanner for codes?

[Flametail]

nyle: it's coming from the driver's side...or at least it sounds that way because it only does it when i'm driving it.

96cali: pretty sure the cat has never been replaced but I'm gonna take it off when I get my exhaust installed.

EDIT: no I haven't had it hooked up. I don't have a CEL so I didn't think I needed to.

[nyle]

what if someone revs the engine while you listen?

[Flametail]

haven't tried that...i'm typically alone while I work but if someone is home tomorrow i'll get them to rev for me.

[tiFreak]

you could always just pull the throttle cable under the hood to rev the engine

[Flametail]

It would be too hard for me to pull it and keep it at the RPM's where it happens. It would just be easier to have someone help.

[roadrash]

Dude, just admit defeat and ask "Miss A." to help ya out. :icon_poke

[Flametail]

Dude, just admit defeat and ask "Miss A." to help ya out. :icon_poke

lol. she would be out there helping me if she didn't have to work. :biggrin:

Roadrash, did you get the bolts and whatnot?

[Flametail]

well I pulled the throttle cable and no rattle...i guess it only happens under load...or I just couldn't hear it because of the normal engine noise.

[nyle]

hmm. i know "pinging" happens under load, i dont know if that is what it is though. anyone else can maybe diagnose better?

If it is pinging, i think you can try switching to a higher octane gasoline and see if it helps. Its something about the way the gas ignites under load.

[Flametail]

it sounds more like a rattle then a ping but i'll try the gas thing.

[Flametail]

Nyle: I went to medium grade gas an have run 3/4 of a tank through it and it still rattles.

I still can't pinpoint where it is coming from though. kinda a pain when it only happens at a certain RPM and under load. I know if I rev and keep it at 2500 while driving it's really loud and noticeable.

[nyle]

you were running low grade? i think the minimum we are supposed to run is 89 octane.


anyway. i'm not sure what it could be. sometimes i just stop in my regular garage and talk to my mechanic for a few minutes to point me in the right direction.

[Flametail]

I never run high due to cost. poor college kid. i've read the octane doesn't really matter for our cars anyways.

I don't have a local BMW mechanic around where I live...they are all about 30-45 minutes away.

[nyle]

any mechanic can help you diagnose.

[Flametail]

I have a feeling that where I live people are gonna tell me they can't figure it out.

[roadrash]

I have a feeling that where I live people are gonna tell me they can't figure it out.
I gave you Konrad's contact info, didn't I?

[Flametail]

I think you did but I can't remember.