Originally Posted By: TiredTrucker
Originally Posted By: RLS
The biggest problem with running diesel oil in cars and pickups is the phosphorus content is to high. It may kill the cats. We had this issue in our fleet when we tried to run 15w-40 in all our vehicles, high cat failures. When we went to running the proper spec. oil in every thing, cat failures when way down.
Just saying.........
I know that most Chevron and most Mobil diesel oils have lower Phosphorus amounts. They also carry the SN rating. A easy way to check is if Ford approved it for their 6.7L, I would not put it in a new car engine.
Just saying........
That is the beauty of living in a state that doesn't check emissions or any other kind of vehicle inspection mandates. Cats fail? Who cares. But that being said, I use a conventional gasoline oil that has comparable phosphorus as many current HD oils in my 2006 Cadillac and it hasn't lost a cat yet.
Quite often when the cat fails, it completely melts down and turns into a solid lump, completely blocking the exhaust and leaving you stranded. They can also get hot enough the vehicle can catch fire.
Many vehicles will also get reversion in the exhaust and suck the cat material back in through the exhaust valves. Engine does not live long after that.