Opinions on Engine Flushes?

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I personally think it is a bunch of [censored]. There are so many detergents in oil nowadays that you should never have to flush your engine as long as you are taking care of your vehicle and are doing oil changes on time. I have been told by many automotive technicians that it can actually do more harm than good and even looking at most manufacture service intervals and recommendations not one of them have ever advised doing an engine flush. I would love to hear what others opinions are and their experiences with HIGH detergent oil cleaning products.
 
No matter what oil you use sludge can build up if the engine is abused and oil changes skipped. If you are playing catch up with such an engine and want to use a quick flush, be very careful. You should have a good idea of what you're up against or you should seek help. This thread should get you a lot of suggestions. If you're not dealing with a sludged up engine don't use an engine flush. Regular maintenance done correctly is all you need. Leave the oil additives and flushes on the shelf where they belong, no in your engine.

For me, I've used Auto-Rx with excellent results even though admitting that here will get me flamed. Auto-Rx has had a rocky ride here at BITOG. Lots of people are experts on how it works even though they've never used it, they just know. It will never gain a following here bor lots of reasons besides how it works. The owner of the company is not a people person, just a good chemist.
 
Originally Posted By: DimondPhilup
looking at most manufacture service intervals and recommendations not one of them have ever advised doing an engine flush


You missed MB. They used to recommend it.

Sometimes it is appropriate. Sometimes not.
 
I use one in my (sludge prone) 2001 Saab 9-5 turbo every oil change (with a sacrificial oil.) Pulls out a fair amount more extra garbage than just a sacrificial oil flush alone. I also use them when buying older cars with questionable history ([censored] imports / old stuff form the 70's, etc..)

If you follow the instructions I doubt you'll have any problems. Whether or not it's needed is on a case by case basis. In some cases I've done 2-3 sacrificial oil changes with chemical oil flushes before I've been happy with the level of garbage coming out.

Horses for courses
Jordan
 
I have done it with safe products like Amsoil flush which contains no solvents. I have seen these products liquefy sludge and hold it in suspension until drained out.

My dad and I did an engine job where the engine had seen long periods between oil changes. We filled it with clean oil and changed the filter, added a bottle of Amsoil flush and idled for 15 minutes. The oil that came out was very thick and black and had chunks that kept plugging the pan's drain on the way out. (Draining the old oil prior didn't have this problem)

We also have tried other flush products both solvent / non-solvent type and the best performance so far is the Amsoil one.

When we popped the valve covers after very little sludge was remaining and what was there was easily taken off.
 
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Originally Posted By: HerrStig
Got a 400 K Camry which has never had a flush. Sometimes they are "dealer profit centers".


I never flushed my Santa Fe in my signature either because I regularly maintained it. But for known sludge monsters or those that don't take care of their vehicles it is a handy product to have.
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A flush can be dangerous. I'd just do short changes for a while with cheap oil instead....say 2-3k miles. Monitor how long it takes for the oil to get dark each time - that might give you an indication of progress.
 
If done moderately, an engine flush can be very beneficial for any new oil to "do" its job.
Done moderately, I don't see a down side to a flush...particularly when getting a used car.
 
Originally Posted By: StevieC
I have flushed engines this bad before opening them up with the Amsoil flush and all it does is liquefy the sludge.





Hence the "dangerous" comment above!

If my engine was THAT bad on a used purchase, I'd think a manual cleaning was in order, then several short OCIs with an oil with good cleaning properties (PYB or M1).

I've used Auto-RX in the past, it does seem to clean as advertised so I would consider that also.
 
What I'm saying is that the Amsoil flush liquefies the sludge so the danger is minimal because the sludge flows like clean oil once loosened and liquefied.

I can't speak for other flush products that might release chunks and not liquify it like the Amsoil flush does. In that case I would agree with you it's dangerous.

I have seen first hand that it does infact liquify it. We went to replace a leaky valve cover gasket and noticed that the engine was a mess like the picture above. We put the valve cover back on, put a bottle of flush in with a new filter and clean oil, idled for 15 minutes (with an already warm engine) and then drained it out. (To make the rest of the clean-up easier)

What was remaining was just the heavily caked stuff that took a screw driver to scrape off surfaces, all the softer mucky sludge liquefied and drained out.

The rest flowed out like thick dirty engine oil.

If we come across another engine I will make a video to show you.
 
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Originally Posted By: StevieC
What I'm saying is that the Amsoil flush liquefies the sludge so the danger is minimal because the sludge flows like clean oil once loosened and liquefied.

I can't speak for other flush products that might release chunks and not liquify it like the Amsoil flush does. In that case I would agree with you it's dangerous.

I have seen first hand that it does infact liquify it. We went to replace a leaky valve cover gasket and noticed that the engine was a mess like the picture above. We put the valve cover back on, put a bottle of flush in with a new filter and clean oil, idled for 15 minutes (with an already warm engine) and then drained it out. (To make the rest of the clean-up easier)

What was remaining was just the heavily caked stuff that took a screw driver to scrape off surfaces, all the softer mucky sludge liquefied and drained out.

The rest flowed out like thick dirty engine oil.

If we come across another engine I will make a video to show you.




Ah ok thanks for the explanation! Makes more sense to me now.
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Originally Posted By: Neely97
Originally Posted By: Merkava_4
My opinion is that they're dangerous.

I agree.


Unless you can get the oil pan off easily to clean out the pickup screen ...

I tend to avoid them
 
Originally Posted By: StevieC
I have done it with safe products like Amsoil flush which contains no solvents. I have seen these products liquefy sludge and hold it in suspension until drained out.



To clarify, this is the definition of a “solvent.”

Amsoil is chock-full of solvents or it would not dissolve solids. If it were not a solvent for sludge, it would be worthless and have no effect.
 
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