Does the Diesel engine flush actually work?

[SOHCman]

As in warm up sludged engine, drop oil, replace with 1 quart of new oil and the rest with diesel fuel to full dipstick mark, run engine at idle for some length of time, drain.

Or will this actually damage an engine, or not clean that well?

Thanks, I am considering trying it on one of my old vehicles and always wondered if this really worked.

 

[RooflessVW]

I wouldn't run it, but you could probably fill the engine to the brim and let it sit.

Drain the diesel/kerosene and do a couple of very short changes with cheap HDEO.

 

[wdn]

Did you say just 1 quart of engine oil and then replace the rest of the oil with diesel fuel? No way would I do this.

Diesel fuel has almost no lubricity at all. I would never use it for a lubricant.

 

[andyd]

First you hafta need the flush. Most BITOGers keep their engines clean enough not to require a flush. I have never felt the need myself. However if I was presented with that Cobalt, I wouldn't hesitate.

 

[wdn]

I am not a fan of engine flushes at all but if you are going to do one at all, at least a tried and true method that is widely used and is not known for destroying engines, Sea Foam. You add 1 ounce of SeaFoam per quart of oil to the crankcase right before you do the oil change, and then drive the car for about an hour.

 

[AlaskaMike]

I would never do something like that to any diesel I owned. The closest I would come to that is what rooflessVW mentions--fill it up with the fuel/oil concoction, but DO NOT run the engine, and follow it up with a couple short oil changes.

When you say the engine is all sludged up though, does it run okay? If so, then you've basically got a solution in search of a problem.

Honestly, there are plenty of detergents in good quality modern oil, so if it's running okay I'd just continue to do normal oil changes and let that clean it up.

 

[SOHCman]

Originally Posted By: AlaskaMike
I would never do something like that to any diesel I owned. The closest I would come to that is what rooflessVW mentions--fill it up with the fuel/oil concoction, but DO NOT run the engine, and follow it up with a couple short oil changes.

When you say the engine is all sludged up though, does it run okay? If so, then you've basically got a solution in search of a problem.

Honestly, there are plenty of detergents in good quality modern oil, so if it's running okay I'd just continue to do normal oil changes and let that clean it up.


I should clarify, this is a gas V8 that was neglected by the previous owner. I will be posting a cut-and-post of the filter soon regarding my desire to flush out the hard particles being knocked loose as time goes on.

So there is also the static diesel flush idea just brought up, get it hot and fill, but don't run?

 

[Delta]

Couldn't you just get something like the Liqui-Moly Engine Flush treatment or the like and be done with it? Seems it would be easier and safer doing it that way.

Are you flushing because of noisy valvetrain/internals or just a piece of mind thing? Honestly if it's quiet I'd just do shorter OCI intervals and be done with it.

 

[ET16]

I would never use a ratio that high.

The off-the-shelf flushes I've seen don't exceed 20%, so max maybe 1 qt in a 5 quart sump. I use kerosene for a flush sometimes, but usually less than a pint for a 4 quart sump.

 

[SOHCman]

Originally Posted By: Delta
Couldn't you just get something like the Liqui-Moly Engine Flush treatment or the like and be done with it? Seems it would be easier and safer doing it that way.

Are you flushing because of noisy valvetrain/internals or just a piece of mind thing? Honestly if it's quiet I'd just do shorter OCI intervals and be done with it.


It's more a concern that it's floating around and possibly plugging oil passages. It's definitely loading up my filter as it comes loose.

 

[Donald]

The CarTalk guys said it trashed all the engines they tried it on. But it worked for others. I would not try it myself.

 

[SOHCman]

Originally Posted By: Donald
The CarTalk guys said it trashed all the engines they tried it on. But it worked for others. I would not try it myself.


Did that include idling the engine with diesel, or just filling a hot engine with diesel and then draining while still warm to carry out crud?

 

[SOHCman]

Originally Posted By: AlaskaMike
I would never do something like that to any diesel I owned. The closest I would come to that is what rooflessVW mentions--fill it up with the fuel/oil concoction, but DO NOT run the engine, and follow it up with a couple short oil changes.

When you say the engine is all sludged up though, does it run okay? If so, then you've basically got a solution in search of a problem.

Honestly, there are plenty of detergents in good quality modern oil, so if it's running okay I'd just continue to do normal oil changes and let that clean it up.


I have been doing reasonable oil changes over the years with quality synthetic to "clean" it, but only recently began cutting filters and am surprised it's still so dirty. It runs good, I work this truck hard, and the cost of a replacement truck is prohibitive.

 

[newbe46]

Using diesel to flush engine does seem to work, at least in this instance.

 

[bdcardinal]

I would be concerned about any sludge carried to the bottom of the pan, not getting properly drained, then clogging the oil pump pickup. Maybe if you could drop the pan and clean it after that would make me feel better.

 

[camrydriver111]

I would not start it with diesel in it, but a static flush might work.

 

[meep]

not aware of the vehicles history, any dramatic flush you do should be followed by clearing out whatever it breaks up, as it could clog the pickup if it's severe. So you might as well just take off the valve covers and scrape the stuff out without chemicals, and if you are really enterprising pull the oil pan and clean it too. No liquid solution will beat this. THEN run short OCIs with seafoam or the cleaner of your choice and enjoy the vehicle.

Not too long ago BITOG was all over some other product, maybe "kreen"?

-m

 

[bullwinkle]

Still like PYB, a good filter, and short OCIs, making sure that the engine is making operating temperature. That Cobalt is pretty much toast, though, sounds like things starved for oil on it. Way back when I was young, we tried kerosene as flush on an old Buick 455 (didn't know any better), spun a rod bearing on it-and that was just idling it for an hour.

 

[BMWTurboDzl]

Years ago I read that one way to de-sludge an engine was to drain existing oil then fill engine with enough kerosene to reach the valves. Let the engine sit for a few days as the sludge dissolves then drain and fill with cheap motor oil/filter, idle the engine for 10 mins or so, drain and refill with motor oil/filter of your choice and you're good to go.

 

[SOHCman]

Originally Posted By: bullwinkle
Still like PYB, a good filter, and short OCIs, making sure that the engine is making operating temperature. That Cobalt is pretty much toast, though, sounds like things starved for oil on it. Way back when I was young, we tried kerosene as flush on an old Buick 455 (didn't know any better), spun a rod bearing on it-and that was just idling it for an hour.


Yikes, was it straight kerosene? It seems I always see people recommending adding a quart or two of engine oil to the mix for some lubricity, or enough lubricity to protect at idle allegedly.