My 05 has had cold start-up rattle for 2 years. Lasts 1-3 seconds and disappears. Haven't run car for 3 weeks so I decided to tear into the engine. Removed valve covers and found the right chain tight, however the left chain would lift about 3/8 - 7/16 inch from bottom guide rail.

Question is what holds the oil pressure in the plastic style chain tensioner over long periods of time? I can't see it being the anti-drain back valve in the oil filter. Maybe I'm wrong? Maybe a one-way valve somewhere. I've read these plastic tensioner's have a seal that blows or leaks slightly between the tensioner and the engine block. I know the older steel versions used a ratchet system to hold the chain tight.

One other problem found. The left VCT solenoid connector had oil in it when I removed the connector. I assume there's no way to fix this other than buying a new one. The oil wasn't visible on the outside of the connector so I guess it isn't relative to my rattle problem.

 

just a thought, but with direction of rotation think the clockwise side of the top gear will be tight from just chain pull- might make it look different from one side to the other...if its still apart, try turning the crank ccw a tad, see it the situation reverses. depending on stop position, pressure from a roller lifter might try to twist the cam slightly as it sits too...

this could be another good reason to consider a accuumulator in the oil line...no dry starts and pretensioned even before cranking Ive been wanting to add one of those to everything for a long time, but never did...

too nice out, time to get outside