Oil additives to clean engine???

[NoAZ68]

Hello,
Have an '85 351w that I installed. P.O. did not seem to change the oil to often as evidenced by the build up of gunk inside the heads (did not find ou until after it was too late)
I was wondering if anyone knows of a good additive or cleaner to clean that stuff out. I have heard of a foamy amsoil product, but cannot find it around here. It is in the truck and I need to change out the main bearings, so I had planned on cleaning it, once or twice, then changing out the bearings. Pulling the motor is not an option...
Thanks.

 

[bigpappa]

I have used some stuff made by gunk called 5 minute flush but not on anything that bad. If everything is clogged up you may have to do it all by hand with some enging brushes.

 

[Alex]

Just use caution, if the carbon and ash clog an orifice or the oil pump then...

 

[74bronc]

I would use the engine flush from Amsoil. I have used it and it works great. I wouldn't start trying to clean all the gunk out with the engine apart. you will create loose crud and stuff which will block passages etc. I would change the bearings, button the engine up, get it running again, and then do the Amsoil motor flush 2 or 3 times to disolve all that stuff inside the motor. That way you aren't creating loose chuncks of stuff. my .02

 

[wildbill]

%) %) %) Motor flush works real good just dont drive it do as the instructions on the can say if it is real bad do it twice good luck. Bill 8) %)

 

[jeff71sport]

My 302 was the same way..nothing wrong with the motor except for the crap building up in the engine so i just change oil every 2.5 months and made sure i would take a road trip.. something long enough to get the engine hot for a period of time maybe 2 hour drive or so and after 6 months alot of the shit was gone...

jeff

 

[BwoncoHowie]

I have cleaned out crankcases using Marvel Mystery oil. Add a quart next time you are down 1 qt and drive it normally for about 500 miles, then change the oil & filt. (In a 5 or 6 Quart system including the filter) Crankcases that hold less than 4 qts you need to use less than a qt of Marvel basically 5 to 1 ratio . The long drives on the highway (1Hour or more) help the cleaning process happen faster. Marvel penetrates and cleans the lifters too.

Parafin based oils like Pensoil and Quacker state seem to be notorious for leaving layers of gunk inside an engine even if you change the oil at the recommended intervals.

 

[Rustytruck]

I had a 67 mustang and used a quart of atf mixed in the oil 300 miles before oil change. It is a good solvent with high temp properties and very high deturgent qualities. You run the risk of knocking something loose and plugging gallies and what not but if you are badly sludged it will help. It will also help free up the crud in the rings and clear the push rod tubes. Dont run it too hard and not more than 300 miles or so. It is much kinder to the seals and gaskits than the solvents. Change your bearings after cleaning the engine 3 times or so. the extra fllow from your loose bearings will help to pass the big particles of crud. Put a cheap filter on (FRAM) after the oil change run it for a week and then change to a better filter. (motorcraft or K&N) if you care. You will be plugging up filters right and left so be prepaired to change them between oil changes.

 

[broncnaz]

old school method was to pour a quart of kerosene in and run for about 20 min. then change the oil and like the others said plan on changing the oil and filter frequently for a while. But you maybe better off just leaving it as is if its got that much build up in it it will take a while to clean it all out and when you do there maybe the possiblity that you just losened all that gunk up a little and it will decide to come out when you think all is well and bye, bye engine