Have you found the factory service manual (FSM) on
www.startekinfo.com ?
Read the chapter regarding the correct procedure for replacement and refit of the tensioner - if you don't reset it correctly you can snap a camshaft.
You don't necessarily need to remove the utility belts to fiddle about with the timing chain, however, the access to the chain guides might be limited with all the junk left on the front. Depends what you are planning to do though =>
If you are replacing the chain I'd examine the condition of the guides - to replace these the front cover needs to be removed. So the junk on the front of the engine has to be removed.