Engine flush products - opinions?

[Oliver S.]

I'd like to get some opinions on using engine flush products to clean the engine internals of deposits accumulated over the years.
One example is this product - put in immediately before oil change and have the engine run for 10 minutes:

https://products.liqui-moly.com/pro-line-engine-flush-1.html

The underlying question to which I haven't found an answer is, if the engine can build up deposits (especially in the grooves of the piston rings and, thus, increase oil consumption) over 10 - 15 years when the engine is always thoroughly warmed up (overland trips longer than 30mls) but the car is used only in spring and summer and even then only every 3-4 weeks. The oil gets changed every two years.

Oliver

[Frank D.]

Re: Engine flush products - opinions?

I wouldn't get too carried away with additives - I use Marvel Mystery Oil for this purpose and have never had an issue and have always been satisfied. Its been around for many decades.

[Domenic T.]

Re: Engine flush products - opinions?

Well, forget about cleaning the ring lands. This is a bit harsh, but I used carb cleaner after warm up, (not the spry can) and ran the car outside because it will kill you with the fumes. Then let it set for a while, not to long because the carb cleaner will start expanding all the seals. Works great for bad seals. then change oil & filter. About a quart will do it. done it many times and works great.
Another is to add ATF to your oil as it is a great lube and it will also clean and do a bit of swelling on the seals and free sticky lifters. Did this for years and always had good results. You can put a quart in at oil change and not worry about changing oil till it gets dark, then do it again.

Dom

[Paul D.]

Re: Engine flush products - opinions?

Years ago (late 70s through mid 80s) we used GM Top Engine Cleaner in that manner to clean deposits from combustion chambers which would often reduce spark knock. Pour 1/2 the can in slowly at fast idle, then pour the remainder in fast to stall the engine. Let set for an hour or so, then start up and drive around to clear out all the smoking. We were not allowed to perform that procedure inside or even close to the shop doors.

[Mark E.]

Re: Engine flush products - opinions?

Why risk causing damage to bearings, journals and the cam from inadequate lubrication by running this stuff through the engine? Continue regular oil changes and your engine will live a long, clean life.

[Oliver S.]

Re: Engine flush products - opinions?

@Mark,
the oil gets changed every two years. In between I drive 1.000 - 1.200mls.
And yes, my fear is damaging more. Since I don't have had any experience with such stuff, I'm asking for opinions.
The other question is if my usage pattern with months and weeks of non-driving enables deposits to build up and cause increased oil consumption thereby over the years regardless of oil change intervalls as described above.

Oliver

[Owen L.]

Re: Engine flush products - opinions?

The other question is if my usage pattern with months and weeks of non-driving enables deposits to build up and cause increased oil consumption thereby over the years regardless of oil change intervalls as described above.

Non-driving isn't going to build up deposits, in my opinion. Deposits collect where there isn't sufficient oil flow to flush contaminants through to the filter; that's going to happen no matter how often an engine is driven. Attempting to "flush" out deposits, I would think, is a fruitless exercise because they collect in the "side channels" of the oil river and there just isn't enough turbulence in those spots to clear them out. If there were then the regular oil flow would keep them from building up in the first place. The only way you can slow deposits from forming is to begin with a torn down, cleaned engine with frequent enough oil changes before contamination of the oil occurs.

I might also argue that deposits themselves aren't harmful to an engine. Think of them as a collector of debris similar to a settling pond. They don't form in bearing clearances, on cam lobes, cylinder walls, etc. because the flow of oil keeps debris moving. To me that means they don't get in the way of lubrication and aren't a concern for component wear.

[Duke W.]

Re: Engine flush products - opinions?

Is there sludge buildup in the rocker boxes? If not, why do you need a flush? If there is a lot of sludge, breaking it loose might cause more harm than good.

I think most of these engine and transmission "flush"products are snake oil.

Duke

[Domenic T.]

Re: Engine flush products - opinions?

Here is where ATF works as a great lube and your oil will get dark fast. Some oils are better to keep the carbon suspended, but when the oil sits for long periods the carbon will eventually settle. Also remember that ATF will soften all the rubber seals, and it actually reduced oil burning and leaks.

Dom

[Mark E.]

Re: Engine flush products - opinions?

The other question is if my usage pattern with months and weeks of non-driving enables deposits to build up and cause increased oil consumption thereby over the years regardless of oil change intervalls as described above.

Oliver

I've put less than 8k miles on my car since the engine was rebuilt in 1989. No sludge or even varnish seen when the oil pan and valve covers were pulled last year. Keep changing the oil at least once year and it will be fine.

[John D.]

Re: Engine flush products - opinions?

From the General...

General Motors Corporation does not endorse or recommend engine crankcase flushing for any of its gasoline engines. Analysis of some of the aftermarket materials used for crankcase flushing indicate incompatibility with GM engine components and the potential for damage to some engine seals and bearings.

[Domenic T.]

Re: Engine flush products - opinions?

John, with all respect, any engine that needed to be flushed during warrantee would never get worked on in a dealership. I think whet we are talking about are engines that were neglected and not ones under warrantee.

Dom

[John D.]

Re: Engine flush products - opinions?

Dom

No offense taken...I guess it's risk versus reward- I wouldn't do it on my 67 L79 with 110k miles that's never been apart for fear of what gunk from the last 50 plus years might get stirred up and circulated through the engine.

[Domenic T.]

Re: Engine flush products - opinions?

John,
Yes, I understand. In my shop, with the front to back breather it was something we did on a regular bassis. ATF was the choice to add to oil and in extream casses when rebuild was time they lasted years.
Carb cleaner was a bit harsh, but it softened the seals and stopped excessive oil burning, The oil pump has the screen as you know, andanything that made it thru was picked up by the filter.
Got pats on the back for saving money for poor folks. Ran a engine going to the junk yard without oil, (Not my idea) because it was rusted. followed behind so we could push it the rest of the way, and it did over 15 miles and was running when it got there. That was amazing.
I do not let time pass before I change oil. I use good oil and never over 2K and over 1K for my classic cars.
!2 to 15 hrs of running on my airplanes works fine with a good detergent oil.
To each his own, and again, no dis respect.

Dom

[Oliver S.]

Re: Engine flush products - opinions?

I read through several security data sheets of various engine flush products available here in Germany (Magic Mystery Oil isn’t). The main ingredient (> 70%) is a degreaser then comes some sort of petroleum and a small amount of acids (1-3%).
I know this can’t be compared to the older pushrod V8 engines, but VW turbo engines with 1.8 and 2l displacement used between 2007 - 2012 were prone to excessive oil consumption after 25.000 mls (up to 2qrt per 600mls) due to a design flaw in the piston rings enabling to build up deposits. Despite regular maintenance, oil changes and driving style. Sooner or later you are impacted - it is almost inexplicable. The ultimate remedy was/is either to have to replace pistons, connection rods ($6.000 including labor, official VW recommendation) or have the piston ring grooves reworked to accept other piston ring designs.
Although not comparable, this raised my question, if a driving scenario like mine over 15 years with long periods of non-usage could also increase oil consumption due to deposit buildup in the ring grooves as well, despite regular oil changes.
I would also never use such flush products in engines never opened with many miles accumulated and perhaps uncertain oil change history before ownership. However, in my case, I know the mileage after the rebuilt and that oil was regularly changed. Thus, I further assume that there might not be many deposits and using an engine flush could be an option to at least think about.
I contacted Shell technical service asking for their opinion, too. Their oil has been used most of the time. If I decide to do a flush, I will use a product explicitely meant for this purpose.

Oliver