Engine Flush using ATF: Good vs. Bad

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mjosoba

mjosoba

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Hey guys, heading up to change my oil in a little while. Had a few questions, and yes, as always I searched; but every combo I tried came up as too short or too many words...? Search is not my friend today. I am about 100 miles past my scheduled change. :(. Oh well, it was unavoidable. So, I am about half a quart low on oil. I am changing filter and oil when I get up to my uncles. Rotella-T SAE 30, and Bosch 3500 filter.

So...

1- I have heard some talk about running a quart of ATF prior to an oil change to "clean out the gunk." What are your thoughts on this? Pros and cons. :).

2- It is about 24 miles of mostly highway driving to my uncles where I will change the oil. Is this too long, or too short if I do use the ATF to clean it out a bit?

Thanks, Michael.
 
Shouldn't be any need to "flush" the engine if you're using decent quality oil. The 3000 mile oil change is a thing of the past. Pretty much any oil on the shelf will go at least 5000 before it starts to not work so well anymore. If you still feel the need to do a flush, use something like Seafoam.
 
Yeah, I don't think "flushing the engine" is a good idea. I have owned many cars and never had their engines flushed. My dad did it to his Ford Falcon (back in the 70's) and the engine locked (new engine was ordered)
 
An engine flush should not be necessary. If you do want to do an engine flush, ATF is not what you would want to use. ATF is simply 10 weight engine oil with less cleaning additives than engine oils. If you feel compelled to do a flush, check out Autorx.
 
I agree, no engine flush is necessary. Just use a good quality oil and you'll be fine.

Why are you planning on using Rotella SAE 30 straight weight oil? Being from Kansas I would think you still get some cold weather and will for a while still.
 
ThePookieBear said:
1- I have heard some talk about running a quart of ATF prior to an oil change to "clean out the gunk." What are your thoughts on this? Pros and cons.
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I don't see anywhere in the Owner's Manual where Toyota recommends putting ATF in the engine. Doing this is a not a good idea. If you feel compelled to "clean out the gunk" then follow Cary's advice and check out AutoRx.

-B-
 
Howdy! IF your oil gets really nasty within a couple hundred miles, then you might need to flush it. Tranny fluid is an old Shade Tree Mechanic method, I would stay away from that, and over the counter products also. I FLUSHED and engine once, and it started leaking like a sieve. Never again for me. If I pickup a rig with a really dirty engine, I just do oil changes every 1000 till it starts looking normal. John
 
Well guys, the overwhelming amount of negative replies led me to not go that route. Thanks for the answers.

chitown- Yes, usually our winters are bizarre. Down to the negatives at night, once a while double digit negative; then up to the 40's or 50's by day. However, this winter has been fairly steady. First couple months, it stayed very, very cold. But, last few months have been absolutely beautiful. I understand your thoughts though. I use 15W-40 usually during the winter, but its been low 40's to low 60's for awhile now. Thanks again guys, Michael.
 
I've flushed a few engines with diesel. What's the worst that could happen? After all diesel makes a great degreaser when rebuilding a motor!

But i would not bother if the engine isn't exhibiting some sort of problem that could be attributed to an oil system issue.
 
ATF flushes and SAE 30 oil? Welcome to 1976. When you go to buy your oil, pick up the new Boston album. It's pretty far out.

Seriously, stick with a modern, multi-weight oil. Read up on bobistheoilguy or search for oil and cary here to get yourself right.
 
WAY back in the day I heard it was good to clean your pistons with ATF.

I took a water bottle and did a half ATF/ half water mix.

With the engine at about full throttle it squirted the mixture down the carburator of my FJ40 (Chevy 327 sm conversion enigine)

It died a few times as I put in too much "mixture", probably didnt help, probably made it worse.

Im sure its an old wives tale, even though its not exactly the same thing, but same idea
 
C6H1206- I use what works well for me. I have read many of the threads posted up by raventai and others. But the fact remains that SAE-30 works well for me. Maintains steadier pressure and is much cleaner come oil change time than any of the others I have tried. And I have never used the ATF, thats why I asked. Now I never intend to use it. Thanks.
 
rove_mcanus said:
What's the worst that could happen?
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The worst? Blown engine would be the worst in my book.
Most likely ill effect? Leaks. Lots and lots of leaks.

-B-
 
No doubt the 30w works ok, but that must make for a tough start in the winter. It seems like undue stress on your starter, and then slow oiling of the top end for several minutes until it warms up. It's not an optimal choice.

A Heavy duty 15w-40 would be a better choice, and a synthetic 5w-40 in the winter better still. There have been excellent wear reports from this motor with Mobil1 5w-40, at least consider something like that in the winter months.

Glad you dropped the atf idea. Nothing good is going to come from that. Despite the hype, these motors don't need a "flush", just regular oil changes.

Funny comment about the Boston Album.:D
 
ThePookieBear said:
C6H1206- I use what works well for me. I have read many of the threads posted up by raventai and others. But the fact remains that SAE-30 works well for me. Maintains steadier pressure and is much cleaner come oil change time than any of the others I have tried. And I have never used the ATF, thats why I asked. Now I never intend to use it. Thanks.
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A straight 30 weight oil will only accelerate wear on your engine as it has horrible cold pumping properties. What are you using to establish your oil is "cleaner" at oil change time, your eyes or an actual oil analysis. If you perform some UOA's which actually measure the wear metals from your engine, you will find that modern multiweight oils deliver better results. There is a reason that straight weight oils are not recommended by any manufacture in the past 20 years.
 
Well, I should have mentioned during the cold months I use Rotella T 15W-40. And I know its still winter, but we have had spring like weather for a month or two now. I'm sure we'll get one or two more winter bouts, but I just went ahead and switched to my warmer weather oil. Winter is 15W-40. Other times is SAE 30.

Cary- No, I don't do UOA's. And, yes I am using my eyes. It "looks" significantly cleaner at the oil change intervals with SAE 30 vs. 15W-40. So, I'm guessing it probably is. But I've been wrong before. I don't see how it could be bad for my engine, other than when its really cold, during which I have 15W-40. And don't the additives that allow the 15W-40 to be variable also cause it to get dirty/sooty faster? Anyway, thanks guys.

Edit: I'm not trying to sound flippant. This is just what I have read through my research. So school away. :).
 
Looking at how "dirty" an oil tells you nothing about it's condition. Actually, it is entirely possible that your 30 weight looks cleaner because it lacks cleaning additives so the oil is not removing soot and other contaminates, while the 15w-40 has a strong additive package and you are seeing the results of it cleaning the engine.

15w-40 for the summer, in temps below 30f, 10w-30, or if it gets below 0f, 5w-30 is your friend. Modern SM rated oils do not have the issues with breakdown and contamination that older oils did. Additionally, to meet SM, most oils use a combination of Group II and III base stocks which are far more durable than the Group I and Group II blend straight 30 weight oils use.
 
Does the same apply to all straight 30's? Diesel included? I had heard that the diesel oils were different, and had strong cleaning packages even in the straight 30 weight oils.
 
ThePookieBear said:
Does the same apply to all straight 30's? Diesel included? I had heard that the diesel oils were different, and had strong cleaning packages even in the straight 30 weight oils.
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I am unaware of any HDEO straight weight oils that also carry SL or SM ratings. Why are you so fixated on running a straight 30 weight oil when there are far better alternatives out there (such as the Rotella T 15w-40 you are already using part of the year)?

Oil has come a long way in the past 20+ years. There are reasons that NO manufacture, truck or car recommends straight weight oils anymore, the least of which is startup wear.
 
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