Hello all, I am new here and I have a problem. My 2005 bmw z4 2.5 has a knocking sound when it idles and when I’m at a low RPM. It goes away after 3k I believe. I had read that it may have been due to the gas I was using since it was the lower end cheapo gas I have put in a gas treatment bottle and currently running it right now. It has seemed to get worse. The only thing I had done different within a week or 2 was add oil. I had full synthetic 5w-30 and the guy at the counter said I should put synthetic blend in to which I did. I don’t know if that’s ok or not but the knocking happened after that. I do drive this car with a heavy foot but I do take care of it as much as possible with the general upkeep and whatnots. please due share your ideas and thank you
Knocking in engine
- Thread starter Makeshift_mechanic
- Start date
Do you have oil in the engine now or has it leaked out.
Last time I checked about 4 days ago it did I’ll check again right now
raymond.harper
Senior member
Make a video of the noise so the members can hear the sound the engine is making. Has the DISA valve been changed?
Will do after I get offf work in an hour thank you for taking your time to respond
Oil is full, I checked the DISA which seemed good
I pulled off the cover and saw oil had leaked on the coils and the ground wire which I dried but still seems to not help it along with that the noise seems to be coming from lower than the intake it doesn’t rough idle and drives almost normal
I pulled off the cover and saw oil had leaked on the coils and the ground wire which I dried but still seems to not help it along with that the noise seems to be coming from lower than the intake it doesn’t rough idle and drives almost normal
This is the link for t
he video and some pictures please. Help
UPDATE !!!! I pulled my coils and spark plugs on a hunch and found 2 things .
1. I found clean oil like if I had just put it in on the coils
2. I found crud and build up below the coil and between the spark plugs
What is the next plan of action plz help
1. I found clean oil like if I had just put it in on the coils
2. I found crud and build up below the coil and between the spark plugs
What is the next plan of action plz help
Motionblurrr
Member
Sounds like your valve cover gasket needs to be replaced. Those gaskets are supposed to be soft and squishy and over time they get hard and brittle and let oil seep into the coil/spark plug areas.
That’s what I was thinking too I had to do it before for another reason and I think I might have cheaped out on the product because I was broke
I had replaced the valve cover gasket to no avail and I’m completely out of ideas i was assuming it was a spark plug but I don’t want o spend all that money if it’s another issue
Motionblurrr
Member
Are you getting any codes? Usually actual misfiring will throw a code and tell you which cylinders it's happening in.
If there is a code, you just swap the suspicious spark plug into another cylinder and see if it throws the code in it's new place. If it follows, it's the spark plugs. If it doesn't follow, you need to swap the ignition coil to another cylinder and see if it follows in the same way.
If you don't have any codes, you could have a vacuum leak somewhere which causes lumpy idling.
If there is a code, you just swap the suspicious spark plug into another cylinder and see if it throws the code in it's new place. If it follows, it's the spark plugs. If it doesn't follow, you need to swap the ignition coil to another cylinder and see if it follows in the same way.
If you don't have any codes, you could have a vacuum leak somewhere which causes lumpy idling.
Motionblurrr
Member
Oh man I just watched this.... that does not sound good.
Sounds like rod knocking. Did you ever run the car with low oil? I could be wrong though but if it's rod knock, your engine is done.
Doesn't sound like a bearing issue to me to be honest. Get a long bar - one end on the engine and other close to your ear and try and work out where its coming from.