Your car has hydraulic valve lifters that are going flat overnight. The "clicking" sound is the lifter pumping itself up as oil pressure builds after startup. 5w20 is an extreme cold weather winter weight oil, and it's not winter yet. READ your owner's manual and find out what the vehicle manufacturer recommends for engine oil. You didn't mention how many miles your engine has, but it MAY be ready for a "High Mileage" oil instead of the super light weight stuff that you have been using.
SAE 5W-20 matches what I found but is it petroleum based or quality synthetic? Maybe your issue can be solved with using a quality gasoline additive or using a one higher octane for one or two tank fulls.
the lifters are what making the noise ! the lifters are draining off overnight and once you start it in the morning they will tick until the pressure builds back up !
i have a 2007 acura tl, not the type s, and it clicks at cold starts but goes away til i start it up the next day, i checked the oil, its level and I've been using ams oil, 5w-20, the recommended type, its supposed to be the best all around oil and with cold starts, ive done research on types of oils ..... what could be the problem?
