I agree on not using Quaker State, I also don't use Pennzoil, or Havoline. The Pennsylvania crude has paraffin in it and it cause sludge to build up. When I was a mechanic use could the motors that ran those 3 oils just from the sludge inside. I use Rotella in everything now, it has a special hi pressure additive because it primarily made for Diesel engines. BTW it not the oil that makes the sludge, its the fuel, I have rarely ever seen a Diesel engine sludge, and a propane/ NATGAS motor will NEVER sludge no matter what oil is used.
You are so Right!! When I was young my father would use nothing but Quaker State, and My Father in Law would use nothing but Pennzoil. After taking the valve covers off a couple Fords that would barely run due to the Sludge built up to the point the valve springs were binding. I quit using either. Two Yrs ago my 318 was burning a little oil, I changed it to Rotella 15-40( mis-stated as 15-30 in my last post) and it quit using oil. My thinking was if it was spec'd for heavy service Diesel it ought to be goood for my air cooled engines. And could not be happier.
I don't own any really old engines and so none are old enough to be spec'd for non detergent oil.
The last few I have bought over the past 10 yrs called for a 10-30 detergent in the operators manuals.
When I bought my Ford 1500 Diesel it was a little over full. My suspicion was that the previous owner did not use the fuel shutoff when it was parked. So I changed it as soon as I got it home. It has about 60 hrs on it since I got it and it is down just a smidge. I will change it before I start Spring garden work.
Edited by JD DANNELS, February 20, 2013 - 10:23 AM.