2002 Buick LeSabre 100,00 miles. last week I used Seafoam treatment in gas tank and motor oil (proper amounts). Yesterday I had an oil change and they added Lucas Heavy Duty Stabilizer They put 1 qt of Lucas and 3 1/2 quarts of oil. (4 1/2 total).. Car was running great prior to Lucas addition to oil but after about 1 hour of driving, the engine started knocking and the car shut down. Initially it wouldn't start but after 1/2 hour cooling of engine it started and was able to drive about 2 miles to get home. It started hesitating/knocking a little just when I arrived home.   I checked the oil cap which was smoking initially when it shut down so oil was very hot.  Then I noticed some foam on the oil cap and in side the oil spout.  NOW when I turn the car on it idles great even now but after driving a short distance 1 or 2 miles it seems like there is no oil circulating and begins to act up again. It doesn't seem like any damage has been done yet but here's my question....Can Lucas Heavy Duty Stabilizer cause the foam in the oil. The car was running great with only the Seafoam treatment but started the trouble after the addition of the Lucas oil product. Regardless, I am removing that fresh oil and doing another oil change as a precaution. I think that that Lucas is too thick and causing air and whipping it into foam which probably isn't lubricating all the parts.  Thank you for any HELP!!