Rattle after oil change that lasts for weeks

[Scuderia]

The engine in question is a DOHC 2.0L in a 2010 Civic Si. Every time I change the oil I get this rattle during low speed driving at around 2500 RPM, and when changing gears; when I re-engage the clutch. It happens when the engine is cold, and with new oil. After the oil has been in the engine for some time (about a month), the rattle goes away. It's the weirdest thing.

I'm guessing it's viscosity related, maybe when the oil is new and cold it rattles, but as it shears down and the viscosity goes down the rattle subsides. But why exactly? I don't know, anybody have any ideas? Thanks.

 

[TheLawnRanger]

Low transmission flluid?

 

[JLTD]

Which oil / filter combo are you using? Does it do it at every temperature?

 

[Ded Mazai]

I guess this has something to do with the clutch splines clearances and the engine crankshaft vibration. Probably the clearances get reduced when the engine/gearbox warms up, and the problem goes away. And on the other hand, the oil viscosity affects the crankshaft dynamics in an unpredictable manner.

 

[ARCOgraphite]

I would try a different oil /filter combos. What I was told by a dealer was "normal" went awayc PERMANENTLY after experimenting with oil and filter combos. I will say I am pleased with Champion Labs branded as Mobil 1 filters - except for the cost.

Also check exhaust mounting integrity and motor/transaxle mount integrity. Any exaggerated vibration from cold engine warmup will be transferred to these parts.

Also, Cold viscosity affects flywheel lateral position ( through the crank thrust flange) which can affect clutch takeup.

 

[BrocLuno]

+1

First thing I'd do is swap in a Napa Gold filter and top up with one grade higher oil. The top up won't add much viscosity, but some. The filter change will alter the ADBV characteristics.

If there is a noticeable change, the rattle is somewhat oil related. If not, it's teh clutch or engine mounts or something else ...

 

[Scuderia]

Thanks for the replies fellas. I think I found what it is; the timing chain tensioner. The timing on the chain is off by a little bit (pics included).I guess new and cold oil makes the chain and tensioner rattle. The car has 57,000 miles, so I’m hoping it’s just the tensioner. I’ll try changing that first as it doesn’t require tearing half the engine apart. And if the timing is still off, then I’ll change the chain. And curse and get all kinds of nicks on my hands lol