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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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4 Answers 4

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'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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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'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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