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Engine flush

Posted: Sat Apr 05, 2008 5:20 pm
by Gray
I've been looking around for some engine flush options for awhile to keep varnish buildup to a minimum and reading the pro's and con's of various off the shelf products but was mainly seeing negative comments on most of those. I happened to read something about an old school mechanics trick of using ATF as a prechange engine oil flush, ie: pull out a quart of engine oil, put in a quart of AFT, idle the engine for about a 1/2 hour, and then drop the oil, so decided to give it a try. I usually check the engine oil fairly soon after an oil change and have been kind of disappointed with the PF VQ40 as the oil usually looks almost the same color as before changing even after a day or two use. I did the ATF recipe yesterday and pulled the dipstick today after doing about 200 miles and got a good surprise.

I've tried several different types of engine flushes in the past on other vehicles but with this one all I can say is WOW, looks cleaner than when I bought the truck...have others heard of this or used ATF as an engine flush. About the only problem I'm having now is I can't see the oil on the stick anymore because it's too clean, but now I'm thinking it works so good there might be some kind of a downside.

YMMV

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Posted: Sat Apr 05, 2008 10:17 pm
by RacerZX
Yeah, I've heard of this before, sounds good. ATF is just really really slippery stable oil with lots of detergents in it. Amusingly diesel geeks put it in the fuel tank to increase the lubrication properties of the fuel.

I'd guess that over filling the oil pan by a quart wouldn't be a huge issue, so I'm not sure it's worth the effort to pull a single quart out before adding the ATF. I certainly wouldn't want to put much if any load on the engine with ATF in the pan. Maybe roll to the oil change place literally a couple blocks away from me, but nothing requiring any real acceleration or work from the motor.

Posted: Fri Apr 11, 2008 2:16 pm
by Gray
Thanks Carl, the ATF engine crankcase flush seems to have done it's job removing the original oil fill carbon/sludge build up and any other oxidization from subsequent oil use, as the oil on the stick is still looking clear as water. :)

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Posted: Fri Apr 11, 2008 4:02 pm
by 08Datsun
I haven't done that to any newer fuel injected car as I haven't seen a problem. I used to do the ATF thing in my older cars such as my old 273 powered Dart, but was warned by an engine builder about clogging the oil pump pickup screen in extreme cases. I've had a look see at the top end in my Maxima's VQ30 with 143k on it and it is as clean as a whistle. I doubt there's much of a problem with your VQ40. There was some talk about sludge build up in some newer Toyota engines for reasons I can't remember.

Posted: Mon Apr 21, 2008 9:10 pm
by Gray
Lol, three weeks since the last oil change and the engine oil is still like the color of water on the dipstick.

YMMV

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Posted: Mon May 19, 2008 5:40 pm
by Gray
About 7 weeks and about 4000 kms on this oil since the last change and the oil is now about a honey golden color with no carbon or other black flecks, just a general darkening of the oil color. As most of this oil usage was during cold weather stop and start city driving conditions I'll likely give it another week or so and then change it out. I think I'll do a used oil analysis as well to see how the Motul 8100 E-Tech Lite 0W30 oil is doing in this engine.

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Posted: Tue May 20, 2008 5:58 am
by boogyman
Greybrick, It's good to see some things aren't myths. How many miles/km's do you have on yours so far? Have you noticed the engine running smoother or the oil pressure change?

Posted: Wed May 21, 2008 5:47 am
by Gray
boogyman wrote:Greybrick, It's good to see some things aren't myths. How many miles/km's do you have on yours so far? Have you noticed the engine running smoother or the oil pressure change?
30K kms on the truck Boogyman and no change in idle noise since new, although I've been expecting the front timing chain noise to start so that I can have the guides changed according to the TSB sooner rather than later. The oil pressure needle in this one always stays at the same spot on the guage with no fluctuation from engine rpm.

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