The Truth About Engine Flush...DONT DO IT! #oilchange #engineflush #dieselengine

I work as a fleet technician for class 8 trucks. We never judge oil by its color (in normal operating use). No matter how new the engine oil is, it will always look black due to the diesel soot. I can replace 42 quarts, literally only crank the engine, and it'll be black. That said, we also do oil samples and send them to Chevron for preventative maintenance testing through their LubeWatch Fluid Analysis Program. The trucks with Sea foam always come back with less contaminates, carbon deposits, copper and phosphorus. I've torn down engines at a million miles that used seafoam BEFORE every oil change and the internal components look brand new. A comparable engine without using seafoam will look significantly worn with excessive carbon deposits. That said, most people who want to use these products are generally the kind of people who actually care for their equipment. They often perform all maintenance as recommended by the manufacturer and usually drive their vehicles with mechanical sympathy. I would highly recommend sending those oil samples to an analysist for a final conclusion, however, I understand the cost and time lost in doing so. I am also curious if the Liqui Moly cleaned most of the carbon buildup before the seafoam did. I personally use seafoam on all my vehicles before every other oil change. I do in fact notice better idling and power restored after every treatment on my smaller engines. The only difference felt on my larger engines is fuel economy.

Leaving a like as the amount of oil you had to buy for this video is eye watering

OMG, what a tremendous work you did! Thank you so much for making this video and for all the efforts and hard work associated. Great content!

So as mentioned towards the end the oil is supposed to hold contaminates in suspension, meaning it is dark & opaque - looks bad but is doing it’s job. I think the unknown factor is the condition of the piston rings and the amount of combustion blow-by. I have seen old aircraft engines (used for training in school) which were pretty worn out - disassembled, cleaned, reassembled - they turn the oil black in 10 minutes, they were thoroughly cleaned and new oil used. It was the combustion products getting past the worn rings.

Great video and a load of testing you did. Thanks! For me as a mechanic, I did a simple test years ago for my own proof. I dropped my engine pan (300,000km Escape), inspected and took pics of the bottom of crank area. Then did an oil change and ran SeaFoam for a few hundred km’s. Dropped the pan again and inspected. Sure enough the bottom of the engine was significantly cleaner. Rather than a brownish stain on all engine parts they looked like new and shiny. I was surprised to be honest as I always run Mobil1 full synthetic or Pennzoil full synthetic the vehicle’s entire life and never do extended changes. I thought the detergents in the oil would have kept it 100% clean but that wasn’t the case. As such, I run SeaFoam through all my engines once every year or two to keep those rings from ever sticking. Never had an engine burn oil since doing this in 15+ years now! :)

Regardless of the outcome I do appreciate your effort and you're a hell of a nice guy

So if you are thinking about an engine flush, just change the oil more frequently. Your engine will thank you.

Very interesting to hear so many opinions about whether to or not to use a flush. I may try one before my next oil change on my 2.0tdi audi. The last change did result in dark oil almost immediately. Great content by the way..

Nice video-entertaining, condense, honest and no crappy music. 10 out of 10.

Bought a used Scion with 180k, changed oil several times within a month and used a flush product each time and had the same results you got. My mechanic friend dropped the pan which had a coating of nasty oil on it, so each flush was just cleaning the pan each time. We cleaned the pan till shinny, now each oil change shows the real changes with flush and they do work, Love your 30mm pointer tool and every garage should have a reloader as just another tool.

I appreciate the thorough testing and effort put into the video. Nice work my guy.

Love the video. To the point, honest, and funny. Instantly subscribed. Thanks, man.

You know regardless if your engine is any cleaner or not your comedy was well worth the time spent watching. May i suggest using a riding mower engine that uses one quart of oil instead of your truck engine lol. Cool video man👌

I am a new subscriber and I can say you are the funniest creator that provides helpful information. On a side note, did anybody else realize that he spent over 600 on oil? Dedication that drove me to subscribe. 😂❤

I have not directly run controlled testing on engine flush products like this, and I think this was a great test. Thanks for publishing your work! My perspective based on my experience as an auto mechanic and an engineer working in gasoline engine R&D is that engine flush products have a very narrow application. "Conventional" (distilled petroleum) oils contain paraffins and other long chain hydrocarbons which tend to fall out of suspension as waxy deposits on surfaces. When these wax-coated surfaces get hot enough, the solid deposits tend to oxidize into "varnishes". Detergents help, shorter oil change intervals help, and good operating conditions (avoiding short trips, not overheating, not running the engine under high load and then shutting off immediately) help. But when lubricating an engine with dinosaur juice, at least some amount of waxy deposits and varnish are probably inevitable. Synthetic oils contain little to none of these components and are much more resistant to oxidation, so they're far less prone to leaving deposits. Synthetic oils are also far better solvents, so they do a better job of dissolving deposits and "self-flushing". However, if you have an engine that has been run for a lot of hard miles on conventional oil and is fully of wax and varnish, and you want to switch to synthetic oil, I see two concerns. First, simply draining the dino oil and refilling with synthetic may lead to a lot of deposits dissolving or breaking free and circulating through the engine until the next oil change. Not good. Second, if you really want to clean all the deposits out, the synthetic oil alone may not do the whole job. Engine flush products are basically just strong organic solvents so they are likely to dissolve more wax and varnish than the synthetic oil ever would. So I recommend using oil flush products specifically when switching from conventional to synthetic oil. However, I don't see carbon suspended in the oil (which causes most of that color change) to be related to engine flush products in any way. That comes from combustion blowby and does not stick to surfaces in the crankcase. It's always there when you run the engine and it floats around in the oil no matter what oil you use. It comes out with the oil whether you use the flush or not. You often have to do multiple oil changes (flush or not) to get clear oil because opening the drain and changing the filter never really removes 100% of the oil, and mixing a small amount of sooty oil in a lot of fresh oil is enough to change the color a lot.

Great video thanks, also, I love your clock where did you get it?🤣

Great video … I personally have used Rotella, Delo or Valvoline Blue for my diesels. As for my gasoline vehicles I have always used Valvoline, Castrol or Chevron oil. I don’t mix my oils; I pick my weight and brand and stick with it, changing/ servicing a little sooner then recommended. Filters were PUROLATOR, WIX, NAPA OR BOSCH for gas, and factory Cummins or Motorcraft for diesel….. Never had an oil or filter failure in 35 years… It’s all about how well you maintain your engine. I like my granddaddy said good oil and filter is cheap insurance!!!

I've never done an engine flush to improve engine oil color, but to unstick the scrape ring to prevent oil consumption. Some piston rings are prone to clogging up and thus sticking rings and all that comes with it. The LiquiMoly helped tremendously in this regard.

You had good conclusions. I am a little older than dirt and have been working on cars foreever. In the 60's and 70's we only flushed the engine because of lifter noise or extream buildup of crap when we had the top of the engine apart and could not clean it all manually. It might be OK but I would say that you lose a large amount of lubrication when the flush is is the engine and a small amount of damage may result. With the new oils (I only run synthetic) I never see anything in the top of the engine as far as buildup. The oils are so much better than the old days. If you really want to clean the engine I would just change the oil more frequently. It is really hard to see the effects with a diesel because of the quick contamination from the combustion process. Great Video!

Thanks for running this test. Very interesting and it's something I've wondered about.