If a car has been sitting for a few years, what method would be best to "de-sludge" the engine?

Most cars I bought and switched to AMSoil, I used their "engine flush". Is this nothing more than kerosene?

 

What I've often heard people do is just change the oil, as the title of the thread suggests. Run the engine for maybe 10 or 20 miles. Then change the oil again. Do this maybe another time or two, and then do one last change for keeps. Maybe change it again after another 1000 miles before before going to the standard every 3000 miles or whatever you normally do.

I don't like the idea of putting chemicals other than oil into the engine. I think the multiple oil change in a short period of time idea is safer and should do the job.

 

This might sound drastic but it works, when I first worked in a repair shop in 1972 the foreman showed us how he cleared sludge & deposits on tired neglected engines; he would pour a pint of diesel fuel into the engine and run it on fast tickover for 20 minutes or so, then drain the oil. The crud that came out was amazing, every time we did this this we would have to readjust the valve clearances - nearly all British engines had solid lifters then - as it would remove deposits from the valve train as well.
Kerosene or flushing oil will do the same job, be sure to change the filter and if you have removed a lot of crud replace it again after a few hundred miles.
Roger.

 

There is little practical diference between diesel oil and kerosene ("paraffin" for you Brits), except that diesel has a bit more lubricity and packs a bit more energy when burned, due to its slightly increased density. I like the diesel idea better, but my inclination would be to say, "Leave well enough alone" and "If it ain't broke, don't fix it."

Just change the oil an extra time or two and be done with it, unless you can point to valid statistical evidence that a specific "cleaning" scheme actually does more good than harm.

- Eric

 

Based on the majority, it seems that the way to go is keeping it simple.