2003 corolla 213k miles
so I was replacing my valve cover gasket and I was doing a little bit of inspecting. Engine still looks squeaky clean and it’s never missed a change. However I was curious and felt the timing chain while it was open and noticed there was a little bit of play in the chain itself. Probably a link or two too loose! But there was still some play in it nonetheless. I wonder what has caused this over the years. I have always been told that these should be firm and tight down there. How dangerous is this? And is it possible to tighten it myself? Thanks!
Well with that kind of mileage it's normal wear. The timing chain and/or tensioner do wear out over time even with regular oil changes. Here's the thing, if you don't hear any high-pitched whinning noises from the timing chain while reving the car, then it's still fine. But if you do hear whinning, then it's too loose and will start to cause problems if not fixed.
If it is only getting that much slack I wouldn't worry. It will tighten up once it is running and with that mileage it is typical.
If you don't hear any abnormal noises while the engine is running I'd let it go. Those chains can go a LONG time before needing a swap.
I'm not sure about how your engine is set up but many engines use a hydraulic chain tensioner that runs of engine oil pressure. If the engine is not running there will be no oil pressure to engage the tensioner and you can get a small amount of slack in the chain. If your not hearing any chain rattle when you give it a few brief revvs in neutral I'd say your ok.
