I've been a lurker/reader for awhile and now a registered user & I was wondering on a reccomendation on engine oil with regards to pennzoil products. I've been using Castrol GTX(white bottle) with no issues ever since 2007 when i bought my current car and i would stock up on about 6/7 x 4.4L jugs every boxing day as Walmart has usually had the oil for $10/jug. These tend to last me for the year. I use either Wix/Bosch Premium/OEM Honda filters. As my oil stock is depleting...this time around it seems Walmart canceled the Castrol GTX sale and has Pennzoi Yellow Bottle($10) and Penzoil Platinum($20) on sale instead. Having never used these before I was hoping on your suggestions/opinions. Some info about the car, driving style etc below... The car in question is a 1999 Honda Accord LX - F23a1. Engine modification wise it only has SRI/SS Header/Magnaflow CatBack Exhaust. The service manual reccomendation is that engine oil must be 5w30 and meet GF-4 Standards and follow an interval of every 3,750 miles (6,000 km) or 6 months (Severe conditions). I bought the car used with 125 000km and it now sits with 255 000km. Ever since have been using Castrol GTX(white bottle) every 4000-5000km(never surpassing the 5000km mark). Every oil change obviously goes along with a filter change of either Wix/Bosch Prem/OEM Honda. I reside in Toronto, Ontario CANADA and the vehicle is parked outdoors all year long. The car is driven in a mix of conditions from easy to hard, and slow to fast. My driving consists of short trips(with regards to personal shopping) and highway for work(30min drive one way). To date the car shows no signs of burning oil or oil leaks aside from a leaky oil pressure switch that was replaced this past summer. It has no hesitation on startups etc. I'm usually a picky person about my vehicles and usually check the fluid levels at least once a week and going as far as giving the suspension a full shakedown once every 2 months. On the last tuneup done a couple of months ago each cylinder showed 210psi all across. With the above in mind...would you recommend Pennzoil Yellow Bottle or Platinum? or not Pennzoil at all? What do you think of the idea of using platinum in the winter months and yellow bottle in the summer?(hoping platinum being a synthetic would aid in cold starting) Any adverse effects to look out for switching from Castrol GTX to Pennzoil?