oh im not going to do it. i was just curious and thought i would ask you guys. i just put my synthetic back in, marked 3,000 miles from current mileage to do my next change and hopefully all will be well

 

I have seen a 305 Chevy drained, filled with kerosene, ran for 20 min, then drained and refilled with oil and it lived.
I personally, wouldn't try it, though.

 

so why did the engine sludge in the first place?? If you change your oil frequently even with any dino with detergents it wont sludge!

 

mmstar, I think I'm going to rename this thread "the thread that will not die"...

 

ha! people just keep d***ing this thread up! one of the longer threads ive seen, besides for the "post a pic" threads.

oh and ryland.....reading your post, all i do is shake my head.

 

ummm....why???

 

cuz you didn't read the first part of it.

we figure his engine sludged because dino oil does not have all the detergents and additives of RP, so it was letting stuff build up a little at a time. when he put the RP in, it brought much of it out of the inerts of the engine into the oil pan and blocked his pickup tube.

this is NOT the case with all engines. the 4.7 (at least the early versions), for whatever design reason, has been especially suceptible to sludge problems.

but just for safety's sake, i seafoamed my engine oil before switching to amsoil, and recommend doing that or going a short interval on the first change with synthetic.

 

It still shouldn't have sludged in the first place. Perhaps the PCV isn't working properly? Dino oil will not cause sludge if changed properly. My Mustang has over 163K hard miles on it and had no sludge at all when I changed the cam and intake not long ago. It has always run dino oil changed @ 3K.
Either the PCV system isn't working properly or too many short trips that don't let the oil get good and hot. is usually the cause.
I understand the RP breaking stuff loose, but it shouldn't have been there in the first place.

 

I would guess that more likely than not, the top of the heads get really hot. For example---all the cracked heads issues we've seen here. When dino oil, or any mineral oil get much over 140F, they do what is called coking, wherein the the carbon particles start forming, and they LOVE to clig to iron components, and settle into areas that aren't flushed with a high flow rate----the top of the heads are a gravity drain. When MMstarted changed to RP, the sludging on top of the heads was well advanced.
The RP broke everything loose in a hurry, and it ended up in the bottom. My Big refrigeration compressors use synthetics these days, but years ago they used high grade mineral oils, and guess what, when the controls for the oil temp went south, they coked. What a mess---and you can't take these apart like an automotive engine,
just keep changing the oil and filters. It gets expensive at 110-165 gallons a change.

So, moral to the story, if you're changing from dino to synthetic on a higher mileage engine like the 4.7. do it by starting with many low mileage changes of dino oil with an engine flush or additive such as Seafoam over the course of a couple of months. Instead of changing it at 3k, do it at 1500miles, everytime, you'll see black oil come out on the drain. Its when the stuff looks like near branf new at the change that you're ready for synthetic.

 

yea, gotta be somethin like that. i haven't heard of any cracked head issues myself, but if there are cases of that then it is almost certain the oil sludge issue is due to heat in the head as well.

and completely agree on seafoaming a couple times prior to switching on the 4.7