After pulling apart a whole engine I can assure you there are no issues with timing when replacing the chain tensioner. You will only have to redo the timing if you dismantle the timing chain sprocket assembly behind the vanos, which you won't be. Replacing the tensioner only should be a pretty simple task.

 

hey i was wondering if you ever fixed this issue! Ive been searching for my leak and after changing the valve cover gasket, and front engine gasket, vanos seals, I finally figured out it comes from that bolt tensioner that you mentioned, i was wondering if you were able to remove it , replace the seal washer and retorquing it without any issues,any info will be greatly appreciate it, thanks Ray.

 

E46 lower Timing chain tensioner oil leak DIY (solved)

The BMW inline engines are driven by a chain that links the timing of the camshafts to the rotation of the crankshaft. Sometimes, the tensioner grows weak and begins to fail, causing the engine to give off an annoying rattle on deceleration. This rattle grows louder as time passes and may become more noticeable at slow speeds. While many people misdiagnose this problem as a failing VANOS unit (see our article on Camshaft Timing and Vanos Unit Installation), it’s more likely to be a failing lower chain tensioner. This may occur in high-mileage or even some low-mileage engines; it doesn’t seem to be uniformly related to the total number of miles driven.

BMW redesigned the tensioner in later years of the E36 and offers an upgraded tensioner that can be used in place of the older one on 325/328 six-cylinder models. Thus, replacing the chain tensioner, which is a very easy process, typically solves the problem of the noisy chain.

Using a 32-millimeter deep socket, carefully remove the chain tensioner from the lower front of the cylinder head. Place a rag or paper towel under the tensioner to catch any excess oil that may leak from the engine. When removing the tensioner, proceed slowly, as it is under tension when you release it.

Installation is as simple as removal. Place a new sealing ring on the tensioner, and insert the tensioner into its hole in the cylinder head. At this point, the two small fingers on the tensioner should line up with a mating ridge on the chain guide inside the cylinder head. If this doesn’t happen, you will have a very noisy, rattling engine when you start it up. To guide the installation of the chain tensioner, stick your finger in the hole in the cylinder head so you can feel the ridge on the chain guide. Hand tighten the tensioner to start, and then use a torque wrench to tighten the tensioner to 50 N-m (37 ft-lbs) for the early-style tensioner and 40 N-m (30 ft-lbs) for the new-style tensioner. Use a new aluminum sealing ring between the tensioner and the engine block when reinstalling the tensioner.

When you start up your engine, listen carefully—it should run very quietly. If the noise is worse, however, then you probably didn’t align the tensioner properly with the chain guide. If that’s the case, remove the tensioner and reposition it. If the engine still makes noise, the problem may lie with the upper chain tensioner (also known as the VANOS chain tensioner) or the VANOS unit itself. In that case, see Project 13.
This great information was provided by Pelican auto parts, the only credit i Take was doing the research for approximately 3 days, surfing the web since i made a reply here and fellow enthusiasts didnt reply and provide any update, which i understand we usually dont check our forums until we run in to a problem but im giving back to the e46 community that has help me so much with their imput, this chain tensioner issue did not have many information provided and this should help all those with the pesky oil leak, or rattle tensioner, good luck.

 

The tensioner is bran new and has no exterior oil leaking. I thought there was something hydraulic because there are holes in the side of the bolt. Also, the rattle is only the first half a second, after that it's completely quiet.

 

Heya. I hope this comes in time. Kindly check your oil level as the rattle you hear on that start and then silences is basically hydraulic lifters without oil then oil gets there and wala its gone. So two things low oil. or oil oil viscosity hindering oil pressure. As for me too i am also dealing with an oil leak from the tensioner. I bought a new one with its metal seal but i guess it wasn't torqued down well. I recently torqued it down but its still leaking so i am confused could my seal be dead already because of not torquing it down and its less than 10 months in. Any ones view could help me out here thanks

 

not even sure how/why I posted in a 10 year old thread. Must have been some kind of a mistake.