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After running the vehicle for a certain distance usually we will change the engine oil. This will not only give engine new life with the brand new oil but will also get sludge and other sediments out of the engine.

So while changing the engine oil, I would like to know whether there is any product or process with which I can get all the oil (also the residue oil and sludge sticking to the engine) out of the vehicle's engine?

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Simple answer - no, you can never get rid of ALL of the old oil - and you wouldn't want to, as you need to keep a film of oil over all the moving parts all the time. The small amount of residual oil will mix with the new oil quite happily.

Oil flows better when it is warmer (as it gets thinner), so the best way to get as much of the sludge and residue out is to do the oil change with the engine warm - just be careful of the hot components!

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I second that, and I would add: let it flush for a while. If you do it yourself, let it tickle down during lunchtime, or even overnight. If you really want to overdo it (and if your car has it) you can take out the oil radiator and let it trickle down as well – Lorenzo Dematté May 9 '14 at 13:24
I remember once from a vendor saying that there will be some additives that can be added to engine oil for getting rid of sludge. Luckily from a simple google search I came to similar product. [link]… – user3065750 May 12 '14 at 4:35
I usually drain the fluid and run two quarts of fresh oil for about 5 mins. Drain that out and replace to spec. – Dee Jan 26 at 2:12

I've always had good luck with the kerosene method. Which is adding about a quart of kerosene to the oil and brining the temperature of the engine up to running temp for 5 minutes then drain. Then I use Mobil 1 full synthetic oil and a new decent filter. After 5000 miles I change the filter. Then at 10,000 miles I change the oil and the filter again. My '86 Chevy suburban has 517,402 miles. It's hard to fight with success like that.

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What does this do, exactly? – I have no idea what I'm doing Jan 26 at 7:36

You could use either Seafoam, or a home brewed seafoam alternative in your crank case to clean it out.

How to use SeaFoam to clean your Engine – The RIGHT way!

OK, you’ve got another can of Seafoam, right? Good. This can is going to be used to clean oil rings and lifters, clean built-up oil residues and contamination from the crank case, and clean the PCV system. You’re going to use 1.5 oz per quart of oil. Check your owners manual (or, again, ask on the forum). If you have a 5-qt oil capacity, you’ll be using 7.5 oz of Seafoam (roughly half a can). While the company claims you can leave the Seafoam treatment in your crankcase until your next oil change, I’ve found that most engines with higher miles have a LOT of nasty buildup, which can really take a toll on your oil filter. Therefore, I like to do an oil change roughly 50 – 100 miles after adding Seafoam.

The other half of the can? Add it to the crankcase after you change the oil if you had a lot of sludgy buildup, OR dump it in your fuel tank at your next fill-up. Seafoam is safe to leave in the crankcase with clean oil until your next oil change, and it’s also a great product to clean your injectors and fuel system. In fact, it’s even credited with helping remove some of the deposits that cause a faulty fuel gauge reading in some cars!

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I've rebuilt a lot of scrap yard engines and those just needed refreshing . I found if you could start them , add about a quart or so of kerosene and bring them up to operating temp run 5 min and dump while oil is hot worked best for me. It will even brake up hardened sludge from overheating

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I had some serious black sludge after not changing my oil for over a year. Ran castrol gtx in it with k&n filter for a month. After that, I did another change with my preferred oil. The "new" oil has about 8,000km on it and still looks very clear.

Castrol advertises the "tri-shield technology" in the GTX oil and from experience, it does seem to work as advertised for getting rid of sludge at least... and I'm a sucker for cheesy commercials: (tri-shield ad)

Doesn't completely answer your question in removing all "residue oil" but you wouldn't want to do that anyways. The oil also protects the parts from oxidization.

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I have found before you go and get ready to change your oil an old Timer showed me this trick , Get a Heavy Speaker Magnet ..About all cars not all have a Magnet pad built in the bottom of oil pan or you can buy a Service Plug to catch all fine Segment in oil any way about 3 days or longer take the round Magnet place over the fill plug or near it don't worry about it falling off be sure it's a very strong one . Then when your ready to remove the plug and Drain the oil you will be surprise to what will come out . Hope this helps anyone to try your Car will like that the old fine shavings are now removed.

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How does this work for aluminum oil pans, as many vehicles these days are equipped with them? – Pᴀᴜʟsᴛᴇʀ2 Dec 13 '15 at 13:00

There is a popular process to get just about all the oil and sludge out of an engine.

Though it is usually done after engine disassembly.

You soak the dirty engine pieces into a hot tank of sodium hydroxide (lye) solution and other cleaning agents. The liquid will chemically react with the oils in the engine and remove it in the process.

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