overkill

In the past I used Kendall 15-40 motor oil. Usually after about 1500 miles, I would need to add another quart to compensate for the oil injectors. I recently switched to Kendall Gt 20-50 , for the summer heat here in Northern Calfornia.

On my way to work one day, the oil light was coming on imtermittently, but the oil pressure looked to be normal. Later that day, I checked the oil level, and it was WAY DOWN. I had to add almost two quarts of oil until the dipstick read full!!

The wierd thing about this incident was that I had only put on only 950 miles since my last oil change. I know that there was several times that I was stuck in gridlock traffic and I could hear the fans kicking on. The only logical explantion to why so much oil was consumed was a combination of the summer heat and the times that I was stuck in grid lock traffic. I can't help but wonder if the different oil weight was a factor in this. Anyone have similar experiences????