Nissan Repair: Possible Timing Chain Noise 1999Sentra, cold engine, 10w30

Question
Many thanks.  I will definitely get 5W30 in it immediately.  Since it only happens for a second or two on start-up and runs fine otherwise, I'll hope that does it.  I just got the Factory Service Manual for it and the chain replacement looks like a big job.  Could just the tensioner be replaced by removing the valve cover and upper timing cover?  According to the manual, the head and the oil pan have to come off to replace the chains.  Ouch!  Thanks again.
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-----Question-----
I just bought a 1999 Sentra 1.6 liter with 99000 miles. Engine runs strong, smooth and quiet. But when starting there is a "whirring/scraping" noise for a second or two which promptly goes away and never comes back until the next time I start it. Happens with a hot or cold engine. Might this be the timing chain tensioner and/or timing chain going bad? I just changed the oil and put in 10W30 as it never gets below zero here.  Might the tensioner require 5W30?  Also, is disaster imminent or is it likely to slowly get worse? I just got the car so I don't know if or how long this has been happening. Thanks.
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Al,

Yes, it is and I would use 5W30 to try to get the tensioner to free up and provide tension sooner.  That is what is causing the noise.  The tensioner is pressurized with oil and that is how it works.  You are right on with this.  If thinner oil does not do the trick you might be in for a chain and tensioner and guide replacement.  It is a day job at the house if you take your time.  Not too difficult but time consuming.

Answer
Al,

Yes, I would go with the oil first.  The timing tensioner requires the cover come off and that means all the accessories and the balancer and everything that blocks the cover coming off.  It is a pain and a day job.  Not too difficult.  But, it takes time to get it taken down and then cleaning all the surfaces is really time consuming.  The chain and related parts are easy.