Paging ShadowsPapa, @ShadowsPapa please come to the courtesy counter

[PyrPatriot]

What's this I hear about flushing/cleaning engines out with kerosene/water/ATF fluid? "Flushing" ranges from just pouring it through, to actually running the engine for about 50 miles, from adding the stuff to what sounds to me as running it instead of engine oil.

@ShadowsPapa I ask for you specifically because I love how you explain automotive stuff. I feel like if you did any of this it would be bad for the engine, but some detergent can be added to clean an engine?

The rest of the hive is requested to contribute also.

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[Blade1668]

I'm not Shadow Papa but I've flushed the engine oil system on and off in a few of my Jeeps with a qt. or so of ATF a few times over the years I've had them 4.0 engines. But not driving around with it, added then set at running for short time then draining out and change oil filter (s) when I have done it I don't put a load on the engine or rev it up just let the engine get to operating temperature then draining. Afterwards I have done second oil change and filter again to clean out any leftover ATF and sludge/ gunk. Is it worth while??? I'm not sure but I've got 250k on my LJ doing it and running just synthetic oil and PH-8 size oil filters not the (half sized) PH-16 size. No I've never ran water though engine other than flushing cooling system, that I do every 3-5 years. I've heard of using K-1 to flush engine oil system but haven't done that.

Hopefully Shadow Papa adds his knowledge to this.

 

[LostWoods]

Different fluids (ATF, for example) will have certain agents in them to prevent and clean build-up. In an automatic transmission, valve body channels are very small and build-up would wreak havoc if they were allowed to stick to the walls. Kerosene is very good at breaking down crap as well so I guess I can see why people would use it too.

If you want to flush your oil system, actual oil system cleaners are available. You do exactly as @Blade1668 said: warm the engine, dump it in and run for 10-15 minutes (you might need to drain a little oil on small capacity engines, not an issue on the JT), then drain and fill as normal. I typically recommended the next oil change after 1,000 miles because some of the stuff that breaks up doesn't flush on the initial drain and fill. I also don't recommend doing this any more than you really have to.

The main issue with kerosene and other shade tree cleaners is that they're not necessarily safe for the components of the oil system... namely rubber seals and hoses. What worked 50 years ago is not the same as today and honestly, I'd be keeping this kind of stuff to the minimum (if at all) and instead just be sure to change your oil religiously.

I've pulled probably a hundred heads when I wrenched and the super clean ones were always the same... some old dude, bought the thing new, uses good fuel and has done oil every 3k like clockwork. Meticulous maintenance with the good stuff will be all your truck ever needs.

 

[Gren71]

I know nothing about any if this. Watching thread

 

[CerOf]

If your rig goes for a swim, I know about draining all the fluids and either putting in diesel or kerosene. It displaces water and prevents corrosion.

In this application, you don’t start anything but turn the engine over by hand. You could pull spark plugsand crank to get it moved through the expensive parts.

 

[Renegade]

What exactly is the point of this again? What is being “flushed” from the engine block of our 2020 Gladiators?

 

[PyrPatriot]

What exactly is the point of this again? What is being “flushed” from the engine block of our 2020 Gladiators?

Potential "sludge" down the road in many years?

 

[Retro Bait]

I will chime in on this since I have done it myself and seen the positive and negative effects.

I did this on old engines before that have either not been maintained or just left to set for years.
What we did is use a mix of 20% oil to 80% kerosene or diesel. In a light scummed up engine (gas or diesel) we would just run it to operating temp but no load. Did this a couple of times and refill with appropriate oil and then change again after a few hours of driving. Usually left engines as clean as factory thenceforth.

Now if the engine has heavy scumosis there is an issue. Seen it happen. The sludge build up was so bad and has eventually cooked into nuggets the the flushing operation knocked them loose and down into the oil pan then plugged up the suction screen. Usually results in a one piece engine.

Done the same thing with coolant contamination in the oil BUT if an engine has been submerged in dirty water all bets are off. Best just to tear it down at that point.

That being said we now live in in an era of tighter tolerances, cam phasers and all sorts of little orifices to plug up. Back in the "good ol' days" you could throw a dead squirrel in an engine and it wouldn't make a whole lot of difference.

The new oils are light years ahead of what was available years ago and I have yet to see a correctly serviced engine ran with appropriate oil "sludged" unless it was just plain worn out and ran past were it should have. I have seen large Cat diesels with excess of 25000 hours clean on the inside.

 

[mazeppa]

Flushing/cleaning? I thought the engine oil and filter were for the life of the vehicle like the transmission oil and filter are.

 

[Factoid]

Flushing/cleaning? I thought the engine oil and filter were for the life of the vehicle like the transmission oil and filter are.

Wow, you are on your way to becoming a billionaire! In a few more millennia those nuggets will become diamonds.

 

[CivilJeep]

As long as the engine isn't being starved for oil, the generally accepted method for cleaning up a sludged engine is to use a newer oil (API SN, for example), and let that oil break down the sludged oil over multiple short oil change intervals (500-1k miles). This is intended to remove the sludge without dislodging so much sludge at once that it clogs oil passages. It is also backwards compatible, so the new oil ratings won't damage older seals and gaskets.

 

[Rex3rd]

@ShadowsPapa

 

[bgenlvtex]

Hmmmm, I'm just going to watch this one for entertainment.

 

[LostWoods]

If your rig goes for a swim, I know about draining all the fluids and either putting in diesel or kerosene. It displaces water and prevents corrosion.

In this application, you don’t start anything but turn the engine over by hand. You could pull spark plugsand crank to get it moved through the expensive parts.

This is a much different situation than simple maintenance neglect but even then, I'd still just be doing oil and instead go to a short interval. Water will end up in the pan through use so it's better to just change the oil out more frequently. If this is a trail rig that sees limited use it might be a different case but still, oil and driving is the best practice.

What exactly is the point of this again? What is being “flushed” from the engine block of our 2020 Gladiators?

Massive neglect. If you change your oil consistently with good oil and use good fuel (avoids fouling) you'll never have this problem within the useful life of the truck.

I did this on old engines before that have either not been maintained or just left to set for years.
What we did is use a mix of 20% oil to 80% kerosene or diesel. In a light scummed up engine (gas or diesel) we would just run it to operating temp but no load. Did this a couple of times and refill with appropriate oil and then change again after a few hours of driving. Usually left engines as clean as factory thenceforth.

Yeah this is what I was getting at with my "50 years ago" comment... older engines are more tolerant and it's a common practice with barn finds that haven't been maintained in decades to use these kinds of tricks. IMO they have no business being done in a newer vehicle and definitely not in place of proper maintenance.

 

[PyrPatriot]

Flushing/cleaning? I thought the engine oil and filter were for the life of the vehicle like the transmission oil and filter are.

Life of the vehicle? Isn't transmission fluid changed at 100k on these Jeeps? Checking the manual, cant find where you find the ATF change frequency

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