How do i replace piston rings on bmw e46 n42 engine

I always do a normal service, change oil, fuel and air filters. Drain your oil and replace it. The oil pump i clean during this service too after oil is drained always good to clean your sump of all fine particles and oil pump too. This just gives ur motor a refresh feel.

The water pump is located behind the power steering pump on this engine, they can be quite fiddly.

Get a shop manual for your car from an auto parts store. In it there will be diagrams and step by step instructions along with a chart of torque values for the head bolts.

My guess is you blew the motor rebuilt it and never changed the catalytic converter.

Ur gonna need to split the engine m8 so u have good access to the block. U then want to remove an clean the old rings an bore out with some cleaning fluid or drop of petrol. Then comes awkward part of replacing pistons with said new rings which will b tight. A good way I found was to run a fairly decent sized but slim cable tie through the exhaust port an down an out the bottom of the head. Its then a simple case of easing the new ring back into position an with a gentle but firm push. Slide the piston back into the bore. The cable tie compresses the piston rings an allows the piston to slide into place with the rings perfectly seated. Its then a simple case of remove cable tie an bolt it all back together an jobs a good un m8. Its a trick often used by petrol an nitro rc car users, but the principle is exactly the same an its a pretty much fool proof method of making sure the rings r properly seated in place. Just remember to take cable tie out wen u dun tho lol. Hope that helps mate. If u get stuck just google how to reseat piston rings using the cable tie technique. It may help if u search for the rc car version as its more in detail an exactly the same principle ok matey

Ignition firing order is 1-3-4-2.

Ignition firing order is 1-3-4-2.

There are a variety of posts on the internet describing the procedure but it can sometimes be tricky. You might have to go to the dealer. If you bought the key there or they know you they might do it for free.

The Castrol Edge is LL04 spec and is fine to use on your car as a replacement for LL01. The oil capacity on the N42 engine is 4.3 litres

replacing the pcv valve will cure this problem