Jim Chambers

I also don't think such a small amount will do any harm and maybe some good. However, I would be leery of the "ATF to clean the engine" technique. My concern would be that freeing up a bunch of sludge would clog some oil passages feeding bearings.
As a teen back in the '50's I destroyed a high mileage flathead Ford V8 by replacing non-detergent oil with the then new modern detergent oil. Probably not a fair comparison, but it would still make me nervous to "scrub" a high mileage 928 engine.

dr bob

ATF is a very valid way to help remove gunk from the engine. If there is much. A regular diet of modern oil really does keep things pretty clean though. Unless an engine has been 'abused' with very extended change intervals, it's likely pretty clean inside already.

ATF is indeed somewhere in the 10- to 20-weight range, and is a single viscosity oil. It has no additives that will hellp neutralize combustion byproducts, so it's not really suitable to use for full replacement. It does have extra detergents and additives designed to get rid of varnish and coking buildup in the trans, and those will do the same for deposits in the engine. ATF is a great additive for those chasing sticky or noisy hydraulic lifters for instance. It may also wash away that varnish layer that was letting the main seal do its job too, similar to the panic-alerts that very early synthetic oil use seemed to 'cause'.

Bottom line: I wouldn't worry at all about having up to a quart of Dexron mixed in with eight other motor oil quarts, especially in colder weather.



I do have to mention that the idea of driving it to an "oil change place" scares me a lot more than driving it somewhere else with the splash of ATF in the sump.

WallyP

I wouldn't hesitate to drive the car with a full quart of AFT added to eight quarts of oil...

axis of evil

I made the same mistake way back with a 3.8 Jaguar engine -about a 3 gallon sump, swapped from "old Fashioned" 30 grade oil to New fangled BP Visco static , one of the first of the multigrades that was totally overloaded with detergents, Within a couple of days it turned an engine I thought was tight (the gunk in there had it sealed up nicely) to a big time smoker, I could not even see out the back window there was so much smoke!
It cleaned it out like a combination laxative/enema.Real fast! like **** through a duck!
Big learning curve, Jag engines not a cheap re-build!

(A pint of transmissin fluid about 50 miles prior to a drain and new filter is a good minor engine laxative,I allways do it in my wifes Ford, but on a 928? is it nessessary if you are running synthetic and changing regually?)

mark kibort

what about 2 quarts of water? sorry, i had to.

Jerry Feather

I'm glad to hear about the flathead and the Jag motors. That's what happened with my 57 Chev 265 engine. After I cleaned it out it smoked--not real bad, but worse that I would have liked. However, all these years I have had in the back of my mind that it might have been the first oil change after the AFT treatment that caused the smoking. I filled the crankcase with kerosene and ran it for few minutes--didn't drive it just ran it, then drained and filled with new oil.

I wouldn't try either with my S4's now.

Jerry Feather

Jerry Feather

I can say that I am no stranger to oil additives. In my airplane I have used Molybdenum, Marvel Mistery Oil and Prolong for about 1500 of the 2500 hours I put on an engine that was labeled at 1200 hours TBO. I finally wore it out, but mainly because of the damage that a swallowed valve caused. After that the oil consumption went up fairly rapidly to the factory recommended limit, so I parked it. It's still waiting for a new engine.

Jerry Feather

axis of evil

Now we are getting into "do at your own risk".
On engines that were really filthy inside I have flushed with a 50/50 mixture of kerosene and diesil, Idle for 20 minutes-DON"T DRIVE!- or load engine, then change oil (and filter) I always thought the kerosene cleaned and diesil being a light oil, lubricated.
Wouldn't straight Kerosene be short in the lubrication department?

dr bob

Kerosene and diesel are pretty much the same thing. I've pickled stored engines in Kerosene for decades with excellent results. Including a Jag mid-60's engine. I currently have several Lotus and Yamaha race engines stored this way. Then into double plastic bags with marine preservative sprayed on everything external before the bag is sealed with a big dessicant bag included.

BUT-- I would never even consider trying to run them with kerosene in the sump. For my purposes the kero displaces any water and completely protects the insides from oxidation. It doesn't lubricate much better than Kibort's 'Aqua-Flush' method. I wouln't hesitate to pump kero through the oil galleys via a filter or even a pressure gauge port to flush crud out of the galleys into the sump area. Generally, by the time a used engine is that dirty inside, it needs a complete teardown and clean anyway as part of the refurb effort.

j.kenzie@sbcglobal.net

I'm sorry for your problem. It does remind me of a good joke:

"Why don't the British make televisions?"
"Because they can't get them to leak oil."

axis of evil

And; An english car that does not leak oil, has run out.

Imo000

I wouldn't ever do that again. It will easily destroy the engine. You probably got lucky and only shortenned it's life by a few years.

dprantl

It's funny the lengths some people will go to make something "clean", even to the point of damaging things. Sometimes it's okay for it to be dirty, you know...

Dan
'91 928GT S/C 475hp/460lb.ft

WallyP

I think that I may have the ultimate "dirty engine" story. I was helping a friend in his commercial garage once, and one of his customers brought in an old Buick that had most of the lifters collapsed. She was a single mom with no money, and desperately needed the car running so she could get to her job.

We pulled the valve covers - the rockers were running in channels in the sludge. We pulled the intake - the valley was so full of sludge that you could not see the cam. The cam and lifters were running in hidden tunnels.

At that point, we decided that desperate measures were required. She had to have the car back that day, so pulling the engine was not on.

We pulled the oil pan and steam-cleaned the inside and outside of the engine, top and bottom. It made one Hell of a mess on the plastic sheet that we put on the floor! We blew the water out with compressed air, put the engine back together, and installed two quarts of cheap oil, two quarts of ATF and a cheap filter.

When the engine started, we got a lot of white smoke for a few minutes. The oil pressure light went off immediately, and the lifters still clattered. The lifters quieted one by one, until we were down to only two or three noisy ones. After thirty minutes of idling, we changed the oil and filter, and took the car for a drive. By the time we got back, the lifters were almost silent, and of course the new gaskets had cured the massive pan and valve cover leaks.

The customer was firmly instructed to change the engine oil at least twice a year. She drove the car for several years with no problems.

And for Mark - an engine will run for a quite a while with a couple of quarts of water in the oil. It will run for a very short time with two quarts of water/antifreeze mix in the oil.

Sailmed

Everything is relevant!
For some - like us folically challenged folk - a bottle of shampoo last 25 years!
The amount of shampoo we use couldn't even make it to the oil sump without being diluted!