Thoughts on getting sludge out...?

[slack]

Hey All,

I posted this on another forum as well but was curious what you guys thought about it.

Any thoughts on what would be the best way to get some sludge out of the engine without disassembling?

I've heard running it for a very short time with a quart of transmission fluid in and then change the oil. I know trans fluid has detergents which is all well and good but I believe it also has some sort of seam sealing agent in it as well. Dunno how bad that could be for the car.

I've also heard kerosene but I'm not going to give that a go.

Maybe a bottle of Marvel before I change the oil again? Sea Foam?

I'm asking because last time I changed the oil in the Oldsmobile it was sludge city. I'm going to change it again at 1500 miles to get some more out but wasn't sure if you guys think running a little something else in there to get some more out would be wise or safe.

My biggest fear is dislodging something and clogging the oil pickup.

Thanks!
-Erik

[sly]

I know several folks that have had good results with Auto-rx. It's much slower than the flush style treatment that Trans fluid gives, so you have much less chance of clogging stuff.

[DinoW]

Heres what my Dad learned me, Drain all oil, put in filter fillled w-ATF, fill motor with ATF, Start motor#### IDLE ONLY #### Run for 10 minutes, shut down, and then do complete LOF with NEW filter.

This will be OK for all pushrod motors that dont have metal damage inside. I have done this many times. it will clean up a lot, it wont clean sludge attached to top of valve covers and places oil does not flow.

[jaywish]

Can't say about tranny fluid but a bit of pint or two of marvel before a change never seemed to cause any problems when I had sludged up vehicles.
That in conjunction with continued short interval changes will do the trick, but it will take time.

If your oil turns really dirty before 1,500 you can change it then, after running marvel for a while.

Eventually the oil will start staying cleaner longer and longer as it cleans out channels in the gunk down to the iron or steel. Like the Colorado river cutting the Grand Canyon.

[gadget73]

Just don't use any sort of high power solvent and try and break it up too quick. I've seen people suggest a gallon of kerosene in place of oil, or dumping in a quart of mineral spirits or other stuff like that. If you break it up too fast, it may well block the pickup and cause bigger problems. Also, solvents make for crap lube. A little bit of whatever each oil change won't hurt it but I wouldn't go using quarts of high power stuff each time.

[IPreferDIY]

I've never had a sludge problem myself, though I generally change my oil at 5,000 km intervals (apparently just over 3,000 miles). The one time that I had an oil pan off, there was some surface discoloration, but nothing that could be characterized as any kind of sludge or buildup. Is there anything besides not changing the oil frequently enough that causes sludging?

[GMFuzy]

Goop* in the spray bottle works like a champ on my diesel Benz

[gadget73]

I've never had a sludge problem myself, though I generally change my oil at 5,000 km intervals (apparently just over 3,000 miles). The one time that I had an oil pan off, there was some surface discoloration, but nothing that could be characterized as any kind of sludge or buildup. Is there anything besides not changing the oil frequently enough that causes sludging?

that, and not ever letting the engine warm up. RUn one without a thermostat or only ever do in-town short runs and it goops up.

[Tiggie]

I think my '82 had a defective thermostat from the factory. It was in two pieces when I changed it at about 118K. Sludge? Yeah... It had little pockets in the valve covers for the valve springs to do their thing while surrounded by sludge. The oil drainback holes were like your arteries after eating Crisco for dinner for 30 years. I never did anything but change the oil - lest the sludge avalanche begin.

[FordMan77]

Don't use Seafoam in it. Numerous reports of it causing engine damage. Like Gadget stated, the solvents in it breaks things up too quickly and can clog passages. I'd go the ATF or Marvel route and just change it more frequently until it's cleaned up.

[RobertB]

If your oil turns really dirty before 1,500 you can change it then, after running marvel for a while.

The same can be said if you add a quart of synthetic oil to the regular oil in your oil change. Run that for 1,500 miles. Change the oil completely again but this time, increase your ratio of synthetic oil to regular oil. Run for 1,500 miles. Continue this procedure until you have 100% synthetic oil in the crankcase.

[lincolnlarry]

I don't get the idea of doing this to an engine. You want to get the sludge out so it doesn't get into the oil and run through the engine. So why MAKE it go into the oil and through the engine? I vote for leaving it where it is. It might even be preventing some leaks you don't want to open up.

[88Vic]

^That's the idea with transmissions, I hear that if the fluid is too old it's better to not change it at all. Same with a flush, you can kill it with a flush by dislodging metal deposits and causing leaks.

[slack]

Thanks for the input guys.

So it looks like Seafoam is out.
Marvel or ATF is a possibility
AutoRx seems to be something worth looking at but seems expensive compared to the other options. (Also it looks like someone spams AutoRx threads across the internet with complaints about it ruining their car... so there's that)

I agree it's dangerous to try out. Maybe I'll just add a little Marvel in and see what I get. The oil in my Oldsmobile is just crazy sludged. It was my grandmothers car and every time I change the oil on it it's mud. I'm thinking it must have went the first 70k miles with very little oil changes in it's almost 20 years of existence...

[ootdega]

There's always the good old-fashioned Italian Tune-Up.