The N55 with pneumatic wastegate (pre-2104) seems to present itself with rod bearing problems at higher mileages. The cause hasn't been definitively nailed down. It could be because the oil circuit wasn't primed after oil filter housing gasket or oil pan gasket repair. BMW later released a SIB on that. Microcracking of the plastic oil pick-up tube has also been suspected as a potential reason.
BMW 335i analysis question
- Thread starter 335iguy
- Start date
In this case, the filter from the last oil change needs to be cut open and inspected. If there's a bunch of visible metallic debris in the filter, then could be the bearings are going south. If no real visible debris seen, then carry on and see what the next UOA shows.
It is possible the previous owner knew he was selling the car and did not change the oil for too long a time. So these numbers may not be as bad as it seems. And he/she may have run the car much harder than an average driver.
I would change the oil at 1,000 miles as you can do it yourself. Call it a cleaning run. Change the filter as well and get a look at the element. Replace with the same oil you normally use and take a sample at another 2,000 miles - send to Blackstone. Put in a new high quality filter. You do not need to get an analysis on your first 1,000 mile run as it will have probably 15 - 20% of the previous oil in it. If the oil on the dip stick stays clean and there are no signs of engine trouble you may want to extend the second run to 3,000 miles. A drop of oil on a paper test strip may be of help too, at any time.
Ali
I would change the oil at 1,000 miles as you can do it yourself. Call it a cleaning run. Change the filter as well and get a look at the element. Replace with the same oil you normally use and take a sample at another 2,000 miles - send to Blackstone. Put in a new high quality filter. You do not need to get an analysis on your first 1,000 mile run as it will have probably 15 - 20% of the previous oil in it. If the oil on the dip stick stays clean and there are no signs of engine trouble you may want to extend the second run to 3,000 miles. A drop of oil on a paper test strip may be of help too, at any time.
Ali
It would be great if it had a dipstick!
They make retrofit dipstick kits. Make sure you do your research. The BMW Motorsports version ($$$) is for a specific oil pan and some of the budget kits may not seal properly (no o-ring).
If you trust the oil level sensor in the car and are just worried about a sample you might look for a good place to install a sample valve (I don't like using a Fumoto Drain Valve for this because you have to drain to much to get a representative sample).
If you trust the oil level sensor in the car and are just worried about a sample you might look for a good place to install a sample valve (I don't like using a Fumoto Drain Valve for this because you have to drain to much to get a representative sample).
This!!
edyvw
$50 site donor 2025
Rod bearings. I have seen N55 with bad rod bearings at 70-80k and with original at 200,000. Usually it is due to inadequate oil quality (“I used synthetic oil”), botched OFHG replacement, low oil level etc. They don’t need a lot to bomb.
Get someone to replace them. Get updated one after 2014 update.
Get someone to replace them. Get updated one after 2014 update.