flushing oils - what your thoughts are on using flushing oil in a worn engine

[31 LaSalle]

Just wondering what your thoughts are on using flushing oil in a worn engine

[Guest]

 When I was 18, I thought that refilling the crankcase with kerosene and letting it idle for a few minutes was a good idea for my 55 Chrysler. Then change the filter and refill with oil.

 I now wonder what I actually did to the car?

 I did manage to put 100,000 miles on it  before I loaned it to a customer who blew the trans.

Edited September 7, 2022 by Roger Walling (see edit history)

[John348]

When I was a kid I had a 38 Chevy that ran great but had a ton of sludge on the upper valve train. I bought some stuff in the auto parts store my Father told me not to use it, I would be asking for trouble. He was right. I ignored his advice and did it any way. That engine went from a little puff of blue smoke, and a little blow-by to looking like I was over heating with all of the blow by, and steady fog of blue smoke.

 

Edited September 7, 2022 by John348 (see edit history)

[Gunsmoke]

The 1931 Chrysler CD8 user manual says to "clean transmission regularly with flushing oil (do not use kerosene)........." so I guess kerosene, which I understand was commonly used, was a no-no for some manufacturers.

Edited September 7, 2022 by Gunsmoke (see edit history)

[Guest]

 I just watched a u tube where they flushed an engine with paint remover!

 Garage 54 on U tube

 

 This channel does all kind of wacky things to an automobile!

 

 If you like doing crazy things, and wonder what happens, it's lots of laughs.

 

 

Edited September 7, 2022 by Roger Walling (see edit history)

[Pfeil]

Every once and a while we in engineering would hear some pretty unusual tales from our dealer network across the country. When our cars started using variable valve timing, we would hear of cam timing advancement that had stopped working or would stick. The oil passages to the solenoid were very small and if an owner didn't change their oil frequently these passages would plug up. Now you know why these newer cars require 0-10W or 0-20W engine oil. Sometimes to get these passages going to the VVT free without disassembling the engine you would drain the engine oil and refill it with Dextron ATF and run the engine for about an hour at 2,000 rpm under NO load and then drain the ATF and refill with the prescribed engine oil. This also works wonders on sticky oil pressurized chain tensioners.

 

 I also use the above method on any engine before an engine teardown to make the clean-up part of the job easier.

[plymouthcranbrook]

I have done somewhat like Roger and done a partial flush with a quart of Kerosene in the crankcase,  idle for 15 minutes then drain refill and change filter. Then I changed the oil again about 500 miles later. I was in my mid 20's then so what that says I don't know. i wouldn't do it today.

[Terry Harper]

Looking at a 1920's manual I have it cautions against flushing with Kerosene. warning that some kerosene with inevitably be left behind to dilute the oil. It goes on to state that draining the oil while warm will accomplish the same thing. They go on to close with "No oil can take the place and perform the functions of metal that has worn away."

Edited September 7, 2022 by Terry Harper (see edit history)

[hidden_hunter]

43 minutes ago, Terry Harper said:

Looking at a 1920's manual I have it cautions against flushing with Kerosene. warning that some kerosene with inevitably be left behind to dilute the oil. It goes on to state that draining the oil while warm will accomplish the same thing. They go on to close with "No oil can take the place and perform the functions of metal that has worn away."

In 1922 cadillac were still washing everything with Kero and gas, so it wasn't just a shade tree technique 

[Eldovert]

Not flushing oil but Amsoil ...I changed the oil in a 60 Pontiac with a 283 (Canadian) that was just loaded with gunge under the valve covers. The engine ran long enough to loosen up the crap and then it stopped running.Turns out the only thing holding that engine together was all the goo.

Cheers,Pat

[Rusty_OToole]

I wouldn't use it. If possible, I would remove the oil pan and scrape it out likewise the valve covers. Be careful to remove all loosened crud, DO NOT let it go into the crankcase it will plug up the oil pickup and burn out your engine, I did this once when I was young and dumb.

 

If I could not clean out the sludge manually or even if I could I would use thin detergent oil like 10W30 and change it frequently a couple of times to clean out the engine.

[rocketraider]

If you're using a butyl cellosolve type flush, the stuff will dissolve, dislodge and clean oil goo- with this caveat. 

 

Once it has done its thing, you MUST remove and clean the oil pan and pump pickup screen.

 

If you're not prepared to do that, probably better not to use it.

 

Eldovert's experience on a badly sludged engine is not unusual. A lot of people believe detergent oil will do the same thing in an engine always run on non-detergent oil. I don't. Reasoning that detergent oil is designed to keep dirt/contaminants in suspension until the oil goes thru the filter, which traps them in the filtration media. Not saying it might not dislodge some sludge, but certainly not on scale an engine flush chemical would.

[yachtflame]

I was once motoring into Martinique and the engine started sounding funny. Turns out the oil cooler corroded through and put salt water in the engine and oil in the salt water. After replacing the cooler, I drained and filled the engine with diesel. I held the kill switch down and turned the engine over for a few minutes then drained it. I did this three times and then filled with oil. Did the same with new oil in order to clean the diesel out. Filled it and started it up. For the next three years while I was Captain if that yacht, every time I changed the oil (every 75 hours) the oil was almost as clean as when it went in. 
 I now do this on all of my engines every few years. I then add it to my heating oil to burn. 
Makes it feel like I’m not wasting the fluids. 

[John348]

21 hours ago, 31 LaSalle said:

Just wondering what your thoughts are on using flushing oil in a worn engine

 One thing we all can agree on is that the engine will not get any "less" worn by using a flushing oil, if anything it will possibly accelerate the wear even more

 

Edited September 8, 2022 by John348 (see edit history)

[60FlatTop]

Klaatu Barada Nikto Brand flushing oil is the safest out there.

 

Colorado River tested.