Atf in fuel tank to clean injectors.

[gooffeyguy]

Hey fellas . Have any of you guys done this before. A old school mechanic told me to do this years ago. I have done it on many of my other cars, but haven't done it to my Denali. Old school mechanic explained that atf is like a solvent cleaner and helps carbs and injector.

If your vehicle is Flexfuel, run a tank of E85. The ethanol is an excellent cleaner and will clean the combustion chambers, fuel lines, and injectors

 

[iamdub]

Hey fellas . Have any of you guys done this before. A old school mechanic told me to do this years ago. I have done it on many of my other cars, but haven't done it to my Denali. Old school mechanic explained that atf is like a solvent cleaner and helps carbs and injector.

The way I see it, ATF is an oil. These engines have enough of a battle with oil in the combustion chambers from the PVC system without directly injecting it there. Gasoline itself makes a great solvent (cleaner), so the injectors are technically always being cleaned and not at the expense of carbonizing the combustion chambers and/or damaging the cats. The key is, as others have said, is to use high-quality fuels, including E85 if your car can burn it.

 

[SnowDrifter]

If your vehicle is Flexfuel, run a tank of E85. The ethanol is an excellent cleaner and will clean the combustion chambers, fuel lines, and injectors

Totally forgot about e85. This!!

Of note: I wouldn't run e85 constantly, particularly in cooler months / if your vehicle is sparsely driven. Just a tank or two will do ya! Reason being: Ethanol is hygroscopic and very cooling (blower guys will get condensation on their supercharger), and will cause rust formation if the thing sits or is short-tripped. Moreso than usual, anyway. IIRC our motors didn't have any internal changes between normal and flex fuel varieties - it was just the fuel rail and high volume injectors. So, I'd be concerned. Could always do my thing and run 2 stroke oil at ~500:1 (1oz/4gal).

Here have a relevant piece of info I managed to find

Tribological challenges in flex fuel engines.

Tribological challenges in flex fuel engines. - Download as a PDF or view online for free

www.slideshare.net

Rusting after 1.5yr use (just google e85 rust):

Pics of my pistons/heads- E85 ethanol

www.modularfords.com

 

[iamdub]

...Could always do my thing and run 2 stroke oil at ~500:1 (1oz/4gal).

I tried this for a few months. I don't drive frequently enough to notice any difference. I ran full synthetic TC-W3 at 1oz. per 5 gallons.

Did you notice anything when you started running it?

 

[SnowDrifter]

I tried this for a few months. I don't drive frequently enough to notice any difference. I ran full synthetic TC-W3 at 1oz. per 5 gallons.

Did you notice anything when you started running it?

2-3% economy improvement. Reallllly minor. Didn't notice it till I went through numbers. But it is repeatable.

idle smoother - had a once in a blue moon misfire at idle that has gone away

Piston slap seems a touch reduced

But biggest reason why I did it is to help stave off moisture / lot rot during lockdowns. And to that end, it seems to have worked. Measured by proxy though - time from start crank to full crank speed in flood-clear mode. Didn't do much digging into it as I have to send in a UOA, which is on my list. Going to change my oil here soon, then probably send in a sample on next change after that and see where we stand. Been putting it off since I did some gasket work to the engine at 148k and I was waiting till I had 20k on the thing before I bothered checking.

 

[ROGELIO A GUZMAN]

Well fellas. Just came back from a trip to the snow. About 200 miles maybe. Filled up the Denali and poured a quart of atf. Drove fine with no issues. I was averaging about 17mpg on the hwy, Going about 70 mph. Remember it's a 2005 6.0 awd rated at 17mpg from gmc.
Denali has over 200k. I think it's doing great for a older Denali.

 

[ROGELIO A GUZMAN]

Well fellas did another run to big bear. Filled up the tank and added Lucas upper cylinder cleaner. 3oz per 10 gallons. On the freeway where it was flat. The Denali was staying at around 19-20 mpg. Doing about 65-70mph on cruise control. Not bad for an old girl.

 

[iamdub]

Well fellas did another run to big bear. Filled up the tank and added Lucas upper cylinder cleaner. 3oz per 10 gallons. On the freeway where it was flat. The Denali was staying at around 19-20 mpg. Doing about 65-70mph on cruise control. Not bad for an old girl.

Nice! I don't think you could ask anything more from her.

 

[RET423]

ATF is used to lubricate the pumps and injector o-rings on diesel engines, not for cleaning purposes; the low sulfur diesel blends cause the moving parts and soft parts to fail much more frequently than the older diesel blends so adding some drain oil from the engine or ATF restores most of the lubrication lost in the low sulfur fuels.

ATF also helps lubricate cylinders and rings on engines that have sat long enough to be dry on the top end, mainly because it is lightweight and easy to get into the cylinders but most guys have their own "favorite" lube for getting old engines to return to service.

 

[iamdub]

...mainly because it is lightweight and easy to get into the cylinders but most guys have their own "favorite" lube for getting old engines to return to service.

50/50 mix of ATF and acetone is a great lightweight, "creeping" lubricant. You just gotta pick an appropriate container.