Yes, you should be cautious about what you put in. If the sludge is not bad put in a thinner high detergent oil a few times to help clean it up, or the high mileage stuff, but it will not do what AutoRx does. Don't play with 10 minute flushes. those are dangerous as they are too fast acting.

Yes, you should clean up an old engine. If the rings are clogging with carbon, the oil cannot flow through the oil control ring, and the compression rings cannot move freely to seal, giving you low compression and oil consumption.

While I have never used AutoRx, I am familliar with the chemistry of it, and have a similarlly formulated product. It combines ZDDP (so don't worry about stipping it off) with Calcium (detergent/dispersant) and Group V synthetic oils in the Ester family that are great solvents. They dissolve crud, carbon, sludge, etc. but slowly. Although some differences will be noted within a few days. After putting it in my almost 20 year old BMW my wife swore that the engine had stalled, but in fact all the normal noises had stopped, but the engine was running. Sometimes during the treatment people get scarred when they see the smoke comming out of the tailpipe and I say "Great, that means you had a lot of crud in your rings that you are cleaning out." Those are engines that were close to seizing or were loosing compresson.

As for cooling systems, electrolisis works great for rust - I did it for my gas tank - but the cooling system should be cleaned with the commercial cleaners available, preferably liquid versions, as I have seen un dissolved chemicals in water pumps. Then rinse twice to make sure you get it all out (with the heater valve open). I believe electrolisis is too strong.  Then put in a good long life coolant. Not the cheap green stuff that needs changing each year.

TTT

//www.minimania.com/msgThread/118353/1/1/engine_flush-_cheap_and_effective

thanks Dan, im gonna bookmark your article, that gives me a real good pointers on how to deal with the mini maintenance 101., i think you're right im gonna stay away from those oil additives, it might jeopardize the performance of my mini..ty

SXSMAn and others:

Robster seems to be wanting to put in an oil additive and run the engine, not dismantle it and do a home-brew chemical wash. He did say "thinking of putting an engine cleaning additive in my motor,it cleans as i drive thingie,".

Robster:

Go cautiously with these kinds of additives. Mini engines are built with ancient technology (compared to modern engines) when it comes to gaskets, bearings, valve mechanisms etc. Putting in chemicals to "clean" the engine may also "clean out" gaskets and sealants and leave you with an engine oozing oil from every joint ( and there are lots of them). These chemicals may also wash off protective metallic deposits built up over time, leaving some components exposed to premature wear.  One example is the solid valve tappets and cam shaft that were protected by the oil additive 'zddp' specifically added to the oil to protect these parts.

Another issue is that the engine oil in a Mini also lubricates the transmission bearings and gears. Start throwing chemicals in and you may damage your transmission. I expect that NONE of these engine additives were designed to go in, or even considered, transmissions.

 The safe and right way is to warm up the engine, drain the sump, clean off the magnet on the sump plug and inspect what you find. If you have fine iron filings, that is normal. A thickness of 2mm or so (mixed with oil) would not be excessive. Remove and replace the oil filter, filling the filter with new oil before putting it back on. Let the sump drain until it stops dripping - the car should be level but tipped slghtly to the right to ensure drainage.

Reinstall the cleaned drain plug, tightening GENTLY by hand so you don't strip the aluminum transmission case.

Clean the dipstick.

Put in fresh oil of the weight specified for your engine (typically 20W50). Allow the oil to drain down to the sump - it is sometimes slow.

Crank the engine with the coil disconnected so that the oil pump has a chance to fill all the passages and the filter. When your oil presssure guage shows some pressure, check the oil level, then connect the coil and start the engine. Check pressure again.

Aftrer you've driven the car for a few days, you may see the oil getting darker. This could be a little old oil washed down and discolouring it, or it may be just carbon. Or the oil may stay clean for months.

If you are really concerned, you could do a second oil change. If you want to get anal, you could send out the old oil for analysis.

By the way, your engine may not be original to the car. From yoiur other post, we can see the engine is painted yellow, which may indicate it is a "Gold Seal" unit - a factory rebuild or replacement. Which may be good news - the engine has much less mileage on it than the car. Read the engine serial number on the plate on the block just above the alternator and look up what it is elsewhere on this website.

Questions are fine, I do think you need to use the resources available to you on this forum Robster. Use the search feature.

Hunter started a very good thread on removing rust, I added to it. //www.minimania.com/msgThread/115862/1/1/Molasses___Water

I've never tried Dimitris's suggestion, I like the idea though. 

Be careful of additives for the engine. Many are ok to use in the engine, but could cause issues or even damage the transmission.

Proceed with caution.

Knowledge is power.

Read Read Read Read, then repeat.

Make informed decisions . 

So, have you replace said oil filter (and oil) yet?
While your at it, check the torque on the wheel nuts. Probably the most common mistakes on Minis is to "go gorrilla" on the poor little things. 40-42 ft/lbs is what your looking for. Anything more and, you might as well order up the studs. Much better for you to chose to change 'em than the studs deciding your fate.

The trouble is with older engines you can open up a can of worms when doing a heavy flush.

its part of the maintenance, considering its a 37year old super vintage car, maintenance is done when the motor is running good, not when it's down. i want to remove the sludge inside the motor before it can cause damage.. my oil filter looks ancient, the previous owner must not have replaced it in ages....still the motor runs good(but until when?) 

id probably use 20%lucas oil stabilizer on my next oil change

"...but dont get me wrong, the motor runs good and strong..."

So, why are you effing with it?
If you have good oil pressure, I can't understand why you might want to screw it up. On the other hand, most likely, the cooling system could probably use a flush.... Not something you can do by pouring in some magic dust and driving around.

my application included the engine block inside! just use a simple 12v battery charger! its very effective when cleaning other engine parts as well! 

that's a good idea dimitris, i'll do it later, if you say apply charge, does it mean 110Volts? or 12V? (from battery), i saw it in you tube, all the white calcium deposits were dislodged from the radiator, very effective.

how bout the motor, do you have someting like an additive to clean engine parts as you drive? seafoam? MMO(marvel mystery oil) etc?

truly? i ve tried electrolisis(google it) topped up the cooling system with water and baking soda. Applied charge, let it overnight, flush the next day, worked like a charm.. 

hi guys, as you all know, i bought a 1977 Classic Mini Special with original motor in it, im really not good in taking the motor apart and clean it, im thinking of putting an engine cleaning additive in my motor,it cleans as i drive thingie, like the "Auto Rx"(google it), its a 37year old motor, god knows whats inside it,and how thick the sludge is...but dont get me wrong, the motor runs good and strong, i just want to clean the inside as much as i can without taking it apart.(which i may end up messing it). any input?