dunnitagain

Seafoam . Put a couple quarts of Seafoam in the crankcase with the oil and run it . It will clean the **** out of it .
Never put seafoam in the fuel , but , it and ATF will clean the crankcase very nicely.

zz28zz

Back in high school auto mechanics class, we got a teachers V8 Mustang that had 67k miles. Teacher had never even checked oil level much less replace it. Pulled valve covers and got abt a qt of oil from each one. Also scraped out a pound or so of sludge. Nastiest eng I've ever seen. Instructor put in 3 qts of cheap eng oil and 2 qts of Varsol. Ran eng at fast idle until you could hear the lifters had collapsed and then drained some of the darkest oil imaginable. Afterwards, he did 2 oil changes with a 30 min idle between each oil change. Eng survived but don't know what happened after that.

253

My brother in law never changed oil,, so after years the lifters were rattling horrible,, i pulled the drain plug and nothing came out, used a screw driver to open the sludge at the drain hole,, finally got old oil out,, installed 4 quarts of 10w30 ,,and 2 quarts of Marvel Mystery oil,,let it idle an hour,, we did that twice ,it worked well,,he drove it another 5 years.

Barnacle Bill

Seafoam was made to also be put in fuel to clean the top end of the motor and carbs/throttle bodies.

Anyway, that's an expensive route to go just for an engine flush. I'd fill with 2 quarts of diesel, pull the coil wire off (supposing this is an older engine with distributor), and turn it over a few times. Then pull the distributor and use the oil pump attachment on a drill to pump that through the engine for a bit. After that, do what the other said and run cheap oil in it for a while and change that and the filter before using the good stuff. This is also a good time to tune up the motor, check plugs, re-time, etc....

ThisIsLivin

Years ago I used to add Gunk motor flush to the really bad motors and let it idle until the water temp came up and drain it. Back then dino oil was all we had and most of it was bad. A trick I use now on my winterized vehicles is to pull the fuel pump relay and crank them over several times until I get good oil pressure on the gauge. Keeps the motors lubed and not starting them keeps the condensation and acids out of the oil.

delsol

i grew up changing oil in a large farm fleet.. run till oil was at temp drop 1or 2 quarts of diesel in the oil depending on engine size. run for a couple of minutes at idle -- drop oil and filters. Always left the plug out as long as possible while changing the filters getting oil set up etc...

Had a guy work for us once -- showed him how to do this technique -- at his next job did everything as i did except didn't leave the oil in and ran it just with diesel for a couple of minutes --- saw the engine at the local machine shop and got the story...

Moral --- it does help keep things clean and won't hurt if done properly -- if your trying to get inch of sludge out of pan --- just pull the pan and clean the oil pump while you're at it....and don't buy anything from that person again!