I am in the process of replacing my timing chain because of the same problem. I found out that it was my upper timing chain tensioner was stuck but still going to replace it and the upper timing chain was going to do all of it but do not have the time it is better to do it all at once and replace as much as you can if possiable so if you do start just be prepaired for a long haul at least two days.
Hey i feel sorry for you because the same thing has happen to me and it s**ks, i am in the same process and i am finding out new things. First you can replace just the tensioner but the best thing is to replace as much as you can, if you want to replace the upper timing chain too you have to replace everything because you have to take off the head to do that and if you take off the head you might as well replace the lower chain cause you are right there. Also you should replace the water pump too because to replace that you have to take off the head too it's definitly a pain. I'm as far as the head removal and will let you know more as i go further also make sure to double check your TDC and mark everything if you go ahead and do this. I also found out that my timing chain was off the mark to my sprocket but i am going by the sprocket marker not the chain marker if you have any questions let me know and i can answer them the best to my knowlegde or someone else on forum will.
Just finished doing a head gasket job on a GA15DE, working out of a GA16DE service manual... you shouldn't need to remove the head to replace the upper chain tensioner, and I don't think you should have to take it off to replace the upper chain. Off the top of my head, steps are:
1) Remove cam cover
2) Remove side/front cover (vertical metal plate where timing chain is)
3) The upper chain tensioner is bolted to the inside of the engine, should just undo with a 10 or 12mm socket.
4) If you want to do the chain as well, you need to undo cam gears, held in with a 14mm bolt each IMPORTANT: before you remove chain, make sure you note down cam/crank positions, if you don't have service manual
5) Replace, bolt back up etc etc.
Replacement chain (if desired)
Liquid gasket (for metal chain cover, also for rubber seal on cam cover if needed)
A wee bit of oil to dip screw threads in?
mm, let me know if you need more info, cos it's late here
Hey Guy's I went through this and I will tell you this if you have high miles replacing the tensions will help with the noise but If I were you I would plan to do the lower also. I went through replacing the upper tension and found out that the noise went away but I still had no power,turned out to have a lower chain that jumped a tooth or two and the timing was out of wack. Best to do both with out a doubt!
alrite i finally got around to changin my upper tensioner it was perty bad shape but im still gettin dat noise im thinkin its the lower tensioner 2 but im not sure and now im even gettin another wierd noise it kinda sounds like if the engine is extremely low on oil but i kno its not if any one knows was wat let me kno