530i - rough idle + stalling when hot/hot weather
 

Hi All
first post here after a high number of searches, but nothing like mine...anyway... hope you guys can help !
2008 530i (i assume it is the N53 engine)

Symptoms: Engine idle hunting very roughly, shaking the whole car and stalling
Conditions: Only on extremely hot days/when driving for awhile (45+ minutes) and very hot weather. Does not occur when engine is cold.

Additional Symptoms: May not be related, but i also have a strong smell of petrol/exhaust fumes in the cabin, which leads me to believe i potentially have a cracked manifold or maybe leaking exhaust manifold gasket...not sure if related though.

I have had a few looks in the engine and underneath and i do have some oil leakage/seepage... can't see from where though.
any thoughts ? a few of my friends have advised it could be a vaccum leak, but if that is the case, why does it happen only when hot ? possible heat expansion of metal causing the leak...therefore only occurs when extremely hot ?

any help or experiences would be great...

thanks guys !!

Geoff

bump

nothing guys ? lol i was hoping some sort of direction or FYI lol

Do a smoke test. Check spark plugs. Never rule out leak if you have not checked it.

took it to the mechanic for a quick look.
there is a small leak from the rocker cover..though he says this shouldn't be the problem.
he says it is most likely the PCV or CCV opening either too much or leaking when really hot.

part isn't too much but labour.... he says it is abit of a pain to get to...

Can you turn a wrench if so just doing yourself. Those are known for going bad. It will take a half a day if you don't know what you are doing. There are plenty of videos on YouTube to follow. Also I would change all the vacuum hoses while I'm doing it

umm

used to be a mechanic and still have all my tools..
but how do i know this is the issue ? i'm not the type to just try and see if this is the issue...

havn't seen any other people having the same symptoms as me... i mean...just doesn't make sense.
only happens when very very hot....crazy idle/hunting then stalls...

You can have someone troubleshoot on your dime or see for yourself. If you are a mechanic it should go a lot quicker. Have you pulled any codes

I had something similar a few years back. It would stumble every once in a while. Read a few threads and took a dive to see if it was the issue sure enough the elbow cracked on mine. I also read that the hose would be brittle and crank while taking things apart so I bought and replaced them also.

awesome advice Sean

i havn't pulled any codes yet, and the engine light did come on once...but not during the stutter/stall... funny enough it came on when i was going down hill..with abit of acceleration... then it went away...
i'll try pull some codes tonight as i do have an ultraguage...see if that works

so just an update regarding this issue.

i have installed an ultraguage to pull up codes, and nothing :( no codes or TCs.

i've now set the scanner to display Engine Temps.... currently...even on the hot day on friday..it has been sitting at 80 - 85 degrees C.
it has spiked to around 90 to 92 when i turned off the car...then turned it back on, which made sense as the coolant wasn't flowing but quickley dropped to 80 again...
i am assuming that if the CCV was broken..it would have high temps/high pressure...what sucks is that the scanner does not show oil pressure..

i will monitor this moving forward and see if it happens again and record the engine/water temps at that time.

deleted - posted to wrong thread