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To flush or not to flush?


Terranovation
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Ok I want to hear your thoughts on this, is it important to flush the engine oil every time you change it or do you do it every 2nd change? Do you flush the engine at all or not worry about it?

What is the best product you have found to give the best clean result?

What else have you used to flush your engine with? Kerosene? ATF? Is it safe to use other liquids that have a degreaser effect in them?

 

I just want to hear your views on this because I was talking to a guy at the local auto takeyourcash store and they say the engine oil flush in a bottle are just kerosene.

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No, this is not important IMO if you change the oil as recommended. I would not lose sleep over this - just change your oil at recommended intervals or more frequently if it really bothers you.

 

The only time you want to deal with these flushes is if you have an engine with sludge problems. Even then I would be wary of some of the urban legends out there regarding these flushes - like ATF. ATF just thins the oil down, there's very little, if any, detergents in ATF.

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I dont know anyone that does. I went as far as using Shell Helix which has a built in detergent in for the first few changes and then moved onto whatever oil takes my fancy.

 

If you were really concerned you could get your used oil tested.

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flushing is only necessary if you don't have access to good quality oil. I use Mobil1 and my engines always end up looking like they're brand new internally.

 

If you do want to use a detergent for cleaning sludge you may have built up, replace .5 quart of oil, with .5 quart of ATF, then change oil in 500 miles. If you have an oil filter cutter you can watch the process of the cleaning.

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I used a quart of ATF in my engine oil it seemed to be cleaner inside from looking inside the oil fill hole. In the past I have also used kerosene but I never ran the engine with it in there, just in case of an explosion or something. I drained the oil then put the sump plug back in then poured kerosene in so it would settle in the sump to loosen up any black goop down there for a couple of hours. When I drained the kerosene out there was a bit more black stuff that came out with it.

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Just remember, anything knocked loose can make it to your oil pan and possibly block your oil pickup. I've used and highly recommend a machine to do the flushing. Can't remember the name of the machine I used to use, but it used a mineral spirits to back flush the system and suck it out the drain plug.

 

 

Oh yeah! http://www.envirolution.com/nvr_home.htm

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Possibly I could use a air gun with a rubber hose attachment to get pressure inside the sump then quickly pull the hose out, would the same principle work to get more old oil out?

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Just keep clean good grade oil in there change as required. If your feeling spunky pull your valve cover to check for sludge buildup. Throw some sea-foam in there to clean most of the crap out if you find any.

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I've never taken the top cover off since I've had this beast, I should do it next time I do the oil change to see what it looks like in there. Will I need a new gasket from Nissan or can you just reseal the old one with gasket goo?

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Possibly I could use a air gun with a rubber hose attachment to get pressure inside the sump then quickly pull the hose out, would the same principle work to get more old oil out?

No do not "blow gun" your crank case. Could easily blow out valve cover gasket, valve stem seals, oil pan, front and rear main seals.... Crank case isn't made to hold positive pressure. PCV is there to ensure crank case is never pressurized!

 

Officially Nissan says to never "flush" engine. Mostly what you will accomplish is to get lots of crap floating loose in oil and probably screw engine up.

 

Mobile 1 full syn oil will clean it up like brand new in 2 or 3 changes keep in mind if you have any small oil leaks they will turn into large oil leaks as crud blocking them from inside gets cleaned away. I had a 1/2 qt per oil change leak turn into 1 qrt per week leak.

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Officially Nissan says to never "flush" engine. Mostly what you will accomplish is to get lots of crap floating loose in oil and probably screw engine up.

I don't completely agree with this. Maybe on newer engines, but ours do just fine. I have done hundreds of engine flushes to Nissans and Infinitis as preventive maintenance. Any flush won't get everything out. But if you are going over recommended intervals for oil changes, it's not a bad idea to have it done/do it once and a while. Again, depends on what the chemical does to the sludge. I know for one, I have held a chunk of oil slugde in my hand and put it in mineral spirits from the flush machine above, and it basicly dissolved in my hand. I've have also done it several time to my pathfinder with no issues. It did quiet up my lifters though.

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Edited by 5523Pathfinder
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I used a quart of ATF in my engine oil it seemed to be cleaner inside from looking inside the oil fill hole. In the past I have also used kerosene but I never ran the engine with it in there, just in case of an explosion or something. I drained the oil then put the sump plug back in then poured kerosene in so it would settle in the sump to loosen up any black goop down there for a couple of hours. When I drained the kerosene out there was a bit more black stuff that came out with it.

They do make several brands of engine case flushes, so why mess with snake oils?

I'm not an expert and rarely use them, but did with our R50 when the first oil change made it seem neglected. I put in the flush, ran it 5-15 minutes warm without load (as per instructions), drained it, filled it up with cheap oil, drove it a day, drained it, filled it up with Mobil1 and a new M1 filter. If that doesn't do it, you have other issues.

Yes, just changing the oil regularly with quality oil should be sufficient, and is worth the difference in price.

 

B

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i do a ATF Flush once per year on my vehicles. i've found it helps out with lifter noise, and makes me feel better lol..

 

my deal is 70% atf and 30% oil. (5qt system, i use 3.5 atf and 1.5 oil)

 

run this for about 10 - 15 mins to get it nice and warm, and circulated through (no load, do not drive) and then i change the filter again, and put fresh goo oil in. i've noticed with my Mazda's its helped alot. (miata's are common for Lifter noise, and my wifes has been more noticable quiet after cleaning)

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I might have to do a proper flush on my engine on its next change. I just changed it tonight and the old oil looked pretty awful (as it did on the last change). Both changes I've done myself I've run a little bit of ATF (probably not enough to do a whole lot) before draining, and this time I had a quart of cheap 10W30 lying around, so I poured that through to flush some more of the dark oil out. The new oil went in so light I can barely see it on the dipstick... guess I'll see how long that lasts!

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Some good tips here guys, another reason I started this topic was that I didn't do an engine flush I just opened the sump plug and left it draining all night to get as much out as possible. All seemed well the next morning. Refilled it with fresh oil, waited 10 mins then checked the dipstick and it's black already with little whispers of clean oil in it. So there must have been a lot of black oil still clinging to the insides of the engine, even after 12 hours of draining!

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Some good tips here guys, another reason I started this topic was that I didn't do an engine flush I just opened the sump plug and left it draining all night to get as much out as possible. All seemed well the next morning. Refilled it with fresh oil, waited 10 mins then checked the dipstick and it's black already with little whispers of clean oil in it. So there must have been a lot of black oil still clinging to the insides of the engine, even after 12 hours of draining!

 

well technically the oil IS designed to cling onto the upper componants so you don't dry start the top end every morning lol.

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My question is this to all the pro flush guys. What effect is the various solvents you are putting in engine have on the seals that are designed to be oil friendly? Yes yes i know only putting them in for short time blah blah... But you are doing so repeatedly. Are valve stem seals hardening, and starting to weep? Valve cover gaskets cracking from inside out.

 

Call me a purist but if component is designed for certain chemicals I'm not going to introduce chemical it isn't designed for. I've seen o-rings designed for one application turned into hard plastic rings because they were used in wrong kind of oil. Just saying because you don't see it doesn't mean its not happening. I'll take Nissan at their word when they say engine flush is not recommended and keep clear.

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I think it's safe enough to utilise atf as an engine flush, it has enough lubricating and cleaning qualities in it to give the insides of the engine a good dousing. After all it is inside auto trans so it can't do any possible damage to the inside of an engine. I've used atf to cleanse bolts and I soak them in the atf for half an hour and they come out nice and clean. I have seen the brown rusty residue left behind in my little cleaning container that I use so I'd imagine a cat engine with atf added, running for 10 - 15 mins is going to have atf splashing around inside, giving the inside walls a good clean, plus the engine doesn't really loose any lubrication inside. The only thing I'd be a little bit worried about would be a really clogged up motor with oil chunks in it. Like someone else said, that goop can clog up oil galleries if it's dislodged from engine flushing, but hopefully the stuff comes out the drain plug anyway. The only way to be certain would be to remove the sump and manually clean it properly with degreaser on the inside and also take the rocker cover off and inspect it from the top.

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I think it's safe enough to utilise atf as an engine flush, it has enough lubricating and cleaning qualities in it to give the insides of the engine a good dousing. After all it is inside auto trans so it can't do any possible damage to the inside of an engine. I've used atf to cleanse bolts and I soak them in the atf for half an hour and they come out nice and clean. I have seen the brown rusty residue left behind in my little cleaning container that I use so I'd imagine an engine with atf added, running for 10 - 15 mins is going to have atf splashing around inside, giving the inside walls a good clean, plus the engine doesn't really loose any lubrication inside. The only thing I'd be a little bit worried about would be a really clogged up motor with oil chunks in it. Like someone else said, that goop can clog up oil galleries if it's dislodged from engine flushing, but hopefully the stuff comes out the drain plug anyway. The only way to be certain would be to remove the sump and manually clean it properly with degreaser on the inside and also take the rocker cover off and inspect it from the top.

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MY issue with the engine flush, is in the cylinder. Over time, we will develope scoring in the cylinder walls. These will be filled with "sludge". When you clean this out, you start blow by. Now, you take an older vehicle with 150k, there will be ALOT of scoring, thus resulting in ALOT of blow by!! I am more inclined to remove my oil pan, clean the sludge out, then do a quick oil change. I usually only go 500 miles then change oil again.

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Unless the engine's been run for a long time without oil changes (or something's fallen into the cylinders), I don't imagine it would need sludge to hold compression. My friend's Chevy, questionable service history, 180k on the clock, showed no scoring when we opened it up for gaskets. Maybe if the engine's good and trashed...

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So, what sold me on engine flushes many years ago, was doing one on a cadillac I used to own. 81 Coupe de Ville Fleetwood with a 368 in it(with that stupid 8-6-4 cylinder deactivation system). Anyway, this was my moms car for years, then it was giving to my little brother. I can't say it had many timely oil changes in any of that time. When I got it, it looked great, but ran like crap. I had done a tuneup on it about a year and a half before this, so I knew it wasn't spark related. I tried fuel system cleaners, induction service and fuel injector cleaning and made little difference. After sitting about 6 months my garage, I wanted to get out in it. I took it to work to change the oil, which again, was not in the best shape. I was a bit skeptical of the engine flush at that time, but thought, what the heck, why not try and clean things up(and a good opportunity to have a first hand experience with it). Upon putting in new oil and filter and firing up, it immediately ran better, idled smoother and was a ton more quiet. It was kind of smokey too and it was almost gone now. I had changed the oil before and didn't have this kind of result. The oil stayed very clean for a long time, even until the time I sold it about a year and a half later.

 

I will say, yes, this is not for a super gunked up engine. With lots of gunk, you've got bigger problems. But, as a way to devarnish the lubrication system to stop buildup, it's worth it in my book.

Edited by 5523Pathfinder
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MY issue with the engine flush, is in the cylinder. Over time, we will develope scoring in the cylinder walls. These will be filled with "sludge". When you clean this out, you start blow by. Now, you take an older vehicle with 150k, there will be ALOT of scoring, thus resulting in ALOT of blow by!! I am more inclined to remove my oil pan, clean the sludge out, then do a quick oil change. I usually only go 500 miles then change oil again.

No, sludge doesn't form in the cylinder, it's carbon deposits. Engine flushes don't remove carbon deposits you have to see a specialist for that type of carbon removal but a lot of people don't think it's a good idea because the carbon buildup keeps the cylinders sealed preventing blow by.

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Here's some more investigating I did, I used an engine flush on my wife's Nissan Navara, poured the stuff in, idled it for 15 mins like the can said, drained the old oil overnight, the oil was very black. Installed new filter and put fresh oil in, checked the dipstick and it's already got black oil on it. So even after using this 300ml can of engine flush, it didn't get everything sparkling clean inside. Much to my surprise because this engine flush wad meant to be the best one you can get.

The name of it is Liqui-Moly. On the can it says 'Removes oil sludge' Hmm that's interesting. Apparently it is a blend of Molybdenum Disulfide, which to me is a fancy way of saying kerosene.

On the can it also says 300ml is sufficient for 5 litres of oil. Well in this case it obviously wasn't effective enough. I don't think even three cans would remove everything. I was expecting sparkling clean dipstick. I think kerosene or ATF would have been more effective. So next time I am going to drain the old oil and run a 30% oil, 70% ATF mix and Il report back with the findings.

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