i do an engine flush once a year as a preventative maintenance. that being said i have a 79 volvo with almost 560k that ive owned for 30 years

You said something that resonated with me. Back in ‘79/80 the very first shop I worked for, I mentioned that I wanted to flush my engine to clean it out. My boss looked at me and said that I might clean out anything that is keeping my engine from leaking in the first place. I eventually just pulled the pan, cleaned it and replaced the oil pump. All my oil changes afterwards were clean. Your advice kept me from making that mistake this weekend with a VVT engine. Thanks!

My hats off to you Eric for sticking with your commitment. Good man

Thank you this video is really helping to me to understand that engine flushing is not required and can harm your car rather then helping the engine.

Personal experience from a 2005 Colorado I had. It had oil burning issues from lots of awful buy here pay here ownership and PCV issues they were already known for. I changed the oil religiously at 2-3k intervals and this slowly fixed the oil burning issues over about 15k and I never had to purchase the expensive valve cover with integrated PCV and the i5 ran like a top.

You have just set my mind, i was just thinking of flushing before oil change, what you said completely clicked in, because my heart was all gunked up, the surgeon fitted a stent to clear the blockage, but in the process the gunk travelled through my pipes and caused a blockage in the main artery in my leg, all sorted ! now i flush my system regularly with Rum ;)

Thank you Eric! This is great information. I suspected flashing and you have confirmed this for me. A greatly needed video!

Really good advice, and I can see your genuine. All the best from Steve in the UK

I have flushed engines in the past but they already had some issues. You made some very good points. I have a 1995 Tahoe with a 5.7 ltr. It was using almost 3 qts. of oil between oils changes. Had 198k miles. It also needed an oil pan gasket so I decided to do kerosene and ATF flush prior to removing the oil pan. It was nasty in the pan and oil pickup screen. The engine now has 252k miles and only uses 1/2 qt between oil changes. I guess my luck is a little better than yours. Good video.

I completely believe what you said about finding sludge that was a mold of gunk under the valve covers because it happened to me. Back in the early 70s, I bought a used Mercury Cougar with, if I remember correctly, a 251 c.i. engine. I had no idea who owed it previously or how it was taken care of. I went to change the oil and it wouldn't accept anywhere near the oil expected oil capacity. So I took off the valve covers and what I found was amazing. There were perfect sludge molds with "Ford" imbossed in the surface from the raised letters on valve covers. They looked just like black Jello molds. Then I took removed the pan and it was half filled with sludge. I'm amazed I even had oil pressure. Of course, I cleaned everything up and I think I ran an engine flush but I got rid of that car as fast as possible. It's amazing how some people don't seem to know that you have to maintain cars.

Exactly what I wanted to hear. It just confirmed what I was thinking. Thank you.

It's exactly as you said - you need to be very mindful of a lot of factors if you're thinking about doing an engine oil flush. Older engines that don't have any fancy controls that can get clogged or damaged are fine. But something like this, you definitely need to think twice. In cases like this, it might be better to just change the oil VERY frequently and religiously. Fresh clean oil can sometimes help to wash away sludge and buildup, rather than attacking it directly and immediately with an engine flush treatment.

Thanks for the tip Eric 👍 I recently watched an interview with the makers of Red Line and the guy recommended the same thing. Instead he performed multiple oil changes with conventional oil (non-Redline) to let the detergents do some 'gentle' cleaning until the drained oil cleaned up somewhat.

Sound advice Eric. Was thinking about doing an engine flush on my 99 Camaro SS 6sp with 85k original miles but I'm glad I caught your video. Also, I couldn't help but notice how clean your shop is. This tells me a lot about you and the way you go about your business. Good luck and I look forward to viewing more of your auto videos in the near future.

I've done two engine flushes, had no issues. I was also prepped to change the rear main seal as well as the front seal.

I feel for you, man...I also was the recipient of bad news after a repair and had to own the problem. As far as motor flushing goes, I have never had a bad result by doing this. It's never a one-off procedure though. My daughter was given a 1999 Accord from her aunt who was moving from Brooklyn, NY to Sacramento, CA. The car only had 72K miles on it, but these were primarily NYC street miles, very little highway miles. Also it looked as though the oil was never changed periodically. Needless to say the stuff sorta oozed out. One day the car started bucking on her and threw a CEL. It turned out the VTEC screen was clogged with gunk. I DID the engine flush, changed the oil, ran it for 1000 miles, ran another flush, changed the oil again and replaced the VTEC screen and gasket. She's put more than 40K miles on it since then, but I religiously changed the oil every 5000 miles with hi-mileage oil AFTER a five minute motor flush. I check and clean the VTEC screen each time. The last few times the VTEC screen was pretty clear. So I think I'm done flushing, but will stick with the high-mileage oil changes. Yeah, it's a pain, but I think I brought this engine a longer life than it would have had if it stayed in Brooklyn.

I'm so sorry this happened to you and her. You worked so hard on that and did so many test drives and nothing happened and then this. :(

The only time we ever talked about flushing an engine when I worked in a shop, was when one came in with so much sludge it came out in chunks. We agreed that a flush would be more problems, the only options were leave it and work it out with oil changes, or take it all apart and clean everything manually. At that point it's only a few steps shy of an engine rebuild, not what the customer wanted to hear. If I remember correctly, the engine ended up being replaced because the VVT kept failing, for obvious reasons.

I like to use marvel mystery oil about 30 miles before the oil change. It lightly cleans from my experience. Great in the gas too. You have to look at the condition of the engine too. Borescope down the dip stick tube. In the valve covers and anywhere it will fit to see if there's large deposits of goo. I think a flush with an external high capacity filter might be ok.

I've used it as a last measure a few times - once I had a Subaru 2.2 that had a sticky valve (and like 270k), I figured before tearing into the thing I'd try engine flush. Followed the instructions exactly, and it resolved the issue! But I agree, it's very likely to get cause debris to get caught in the pickup or somewhere else and cause oil starvation.

I've change my oil every 3 months or 3,000 miles for the last 20 years on my Xterra. The last couple of years I've been adding the recommended amount of MMO with the oil and filter changes. Haven't had any issue, but then again the internals were extremely clean even after 20 years

I run synthetic in my tdi for years. Had to replace the oil pan and was no sludge at all. Took the head off a few years latter and same no sludge and clean up top. Now in my case I always used synthetic, changed oil all the time, I commonly run my engine for 3+ hours straight at least 4 times a month. 250,000km

I had good luck flushing my old GM 3100 years ago. Now I own an 08 accord that has a K24 with a quarter of a million miles on it. You just confirmed my worst fears about flushing that engine. Thank you for that Eric. Also, I went to walmart to get oil for my next oil change and wouldn't you know it? Barely any conventional oil. It was all either synthetic blends or full synthetic.

Trans fluid does wonders before a oil change. Had a old 350 with sludge. Ran out of oil and had to limp it home with transmission fluid. Engine was spotless after a few oil changes when the engine was parted out in running condition. Sludge was discovered when a Elderbrock intake was installed with new valve cover gaskets. When the intake was removed, the lifter valley and cylinder looked brand new, but coated in oil.

Eric, whilst I don't disagree with you about super sludged up engines, I've had good experiences reducing oil consumption by doing a flush. It's important to do it methodically, I always run the flush with FRESH oil. That means, 1. Do an oil change, drive the car a bit. 2. Do the flush oil change. 3. Do another final oil change after 500 miles. Doing this on a few Toyotas has reduced oil consumption and improved compression (tested) which has stayed healthy by follow up with 5k oil changed. Most people don't do all of this before and after flushing so maybe don't get all the benefits. Sure it carries some risk, but if you do it this way it's pretty low. I've tried LiquiMoly and SeaFoam.

Didn't think about this, but this may explain how I blew up my 340 Wildcat all those years ago. Had the car for a couple of years before I took off the valve covers. Lots of gunk, so I flushed it with transmission fluid. A month later I noticed a tickticktick and before I could investigate, an end cap came apart and sent a connecting rod through the side of the block. There were words said and tears shed. Never thought to look at the oil pump pickup.

Thanks, Eric well done. I was a few hrs to fuck up my engine with Penrite engine flush. Keep up the good work. Cheers

Thx for clearing that up , honda civic with 330,000 on it with very infrequent oil changes has a oil leak from the front crank seal but apart from that it runs great, still has the original factory clutch in it too.

In my case works pretty dam good, I used liquid molly twice, so two flushes. It was a 2001 silverado with 5.3 the worse lifters noise ever, after those two flush and good synthetic oil the change was day and night. The noise disappear and oil pressure over 40 psi warm, it did work for me. But you guys know, every engine is a different world.

Aw man, all that work. Hopefully the salvage engine has better luck. I guess the plus side is we get more content🤷‍♂️

Thank you for this valuable info.

Thanks for that information Eric 👍

I switched to synthetic for my daily driver a year or two ago, kept my eyes open for leaks in case sludge was helping the gaskets, all good. I wouldn't do an engine flush unless I'm doing a full teardown, and even then...the engine is in pieces, just clean up as you go.

I have never used an engine oil flush product mostly because I am fanatical about maintenance. A few months ago I replaced the valve cover gasket on my 160k mile 2003 Mini Cooper which I’ve owned since new and personally done about 97.5% of all the maintenance and repairs in its life. The valve train on that engine was immaculate, shiny clean. It’s always had full synthetic oil changes with genuine Mini oil filters at about 10k mile intervals.

My heart sank into my shoes when you said it blew up. I have the same EXACT fears when I do rebuilds. Worst absolute feeling.

Hi there. I just discovered your channel. You have some wonderful content. In regards to oil flushes, in the 36 years of driving different vehicles, I have NEVER used oil flush additives. Many years ago, an old Mechanic explained to me the consequences of using oil flush. This is the exact same advice you have just given to all your viewers. When I purchase a vehicle (second hand mostly) I change the oil and drive it for approx 300km, (186 miles) until the oil becomes dirty. Then I change both the oil and the oil filter. Sometimes I've had to change the oil about 5 times until the oil becomes clean. Finally I regularly change the oil every 5000km (3106 miles) with a good quality synthetic oil.

No good deed goes unpunished

With some sticky lifters on and MX5/Miata, I used some engine flush fluid - filled it up, went for a gental drive down the motorway, got it nice and warm. Dropped the oil and it cleared the hyro lifters out. Never had that issue again. I wouldnt recoommend it though. Just change it more frequently.

Only for my own vehicles & only when I first buy them & think it's needed I do a (flush/cleaning) procedure the first few oil changes using diesel fuel. The way I do it the engine never gets very hot & it is a fairly slow process. I have three vehicles, all over twenty years old & pretty clean inside & out. I do 100% agree with you on these flushes that are more of a internal wash.

I literally clicked on a video from you today because its my Birthday. Thanks Eric!!!!

Modern detergent oils are designed to break down sludge and varnish while keeping it suspended in the oil. It breaks things down slowly over time allowing the oil filter to do its job capturing the contaminants. And just like Eric said, modern oil already does everything you need it to do. All these flushes, oil treatments, and stabilizers are quite litterally engineered into our modern oils. Half the reason I quit working at a car dealership was all the bs services I was supposed to push.

My 62 352 ford has sludge and ive been slowly getting it out with marvel mystery oil every oil change.

Very good advice !

Agreed. Nothing good ever comes from flushing over proper cleaning, and timely fluid changes is the method to properly clean components. Not just engines.

The only things I ever flush are toilets and cooling systems.

My camry engine was filled with gunk from a previous owner that rarely changed the oil ,the whole top end ticked like crazy. I used nulons oil flush, changed the oil twice after 2 heat cycles and the inside of the engine was immaculate and it never ticks. That was 200 thousand kms ago

I will say, I have had good luck with one circumstance using BG EPR. It was on a 2014 Grand Cherokee that has issues with the oil pressure sensor. Check engine light kept coming on telling me the oil pressure was low even though it wasn't. Shop told me I needed the pump replaced. Tried the BG stuff (44k, EPR, and MOA). Never had an issue again.

Thank you for making this

Change the oil+filter once a week,for a while. It's worked well for me. Good old Valvoline 10W-30 is still on the shelves here,and is what I usually use.

Only "engine flush" I ever did was on a 3.4L V6 in a 94 camaro. Oil was THICK. So, I pulled the engine, took everything off minus the oil pan and rotating assembly, put it in the back of the truck and went to the car wash. Power washed everything out until it was brand new looking. Then, just to make sure, I soaked it in purple power for three more days and washed it off again. Never had an issue after lol.

I had horrible sludge on my Nissan frontier v6. It was unbelievable when I removed the valve covers. I just left the valve covers off and pressure washed the rockers as good as I could and spray the 0° nozzle down the holes etc. Drained the oil and refilled it and it's been good for 5 years now. People think I'm crazy but I recommend everyone to do it. As long as you drain the oil it's fine

Thanks Eric, I have a 2006 Honda Odyssey with 206k miles on it... and i was about to flash the engine with the mixture of 1 gallon ( half diesel and engine oil ) .... but know I now the out come of doing that, So let stay with regular and frequent oil change... Thanks again

That absolutely sucks that the van came back. I know this must really bug you considering all the work you’ve put into the vehicle to help a person in need.

Best engine flush is cheap oil, good filter change it every 500-1000 miles. Done it with several cars, had great luck with it. You can also add 1/2 at of atf in the oil.

I've got the same van. Mine is an '05 EX model. It's been plagued with the dreaded cat code for many years and the engine vibrates noticeably when the VCM kicks in. She's at 305k miles now and I'm looking to keep her going for as long as we can. After watching this van's fixing it forward series I'm pretty convinced I need to just go ahead and replace my cats. I too considered the VCMuzzler but I have shied away from it and I think your experience reinforces my decision not to install one. Now I'm considering replacing engine mounts in the upcoming timing belt/water pump service that I need to do soon. Thanks for all you do Eric and keep up the good work!

Always been afraid to use the motor oil flush, thank you for verifying my fear, easier to just take it apart and clean it.

Last time I engine flushed, kerosene, was my 318 dodge truck. Nixon was in office. Today? Not a chance.

Sage advice even on an old 70’s or 80’s engine. A hard flush breaks all that crud loose and goes STRAIGHT to the pickup tube and plugs it. Restricting oil flow to any part of the engine is a death sentence. Peace

I got an 07 Scion tC. It has the infamous 07-09 model’s oil burning issue due to bad piston rings - factory issue - and the gunk that creates. So I just used 0W-20 high mileage oil. I changed the pcv valve, and the hose it mates to. 1st oil change. So far so good.

Thx for the advice 👍

This is similar to running Seafoam through engines with high miles. If you're gonna do it then do it from the beginning on a clean engine to keep it clean.

Eric I have always run 1 quart of diesel fuel inside pf the engine just before the oil change. Drain 1 quart oil out, fill. one quart Diesel back in. Run the engine for twenty minutes at 2500 RPM, and drain oil. Keeps the engine lubricated and clean. Never a single issue.

I bought a used Ford Taurus non-turbocharged and follow severe service schedule because I live in Minnesota. I had the transmission drained and refilled. I get about 28-29 mpg on the highway. I change trans fluid every two-three years.

Excellent advice.

I’ve flushed 100’s of engines, a clean engine is a happy engine. That being said, yes bad things can happen, but a sludged up engine isn’t a happy engine. The key is maintenance from the get go.

This popped up in my suggestions, right as I've been thinking about using a flush on my Volvo... Weird. Anyways, I called a shop that specializes in Volvos and asked them what can be done for excessive oil consumption (Volvo inline 6 engines run forever, but they drink a quart of oil every thousand in the process) and the shop foreman's answer surprised me: Liqui Moly engine flush, then an oil change replacing 20% of system capacity with Lucas oil stabilizer. He said they had a Mini in the shop that ate a quart every 700 miles. By doing this procedure, it slowed down the consumption to a much more forgivable quart every 2500 miles.

I have to admit, I did have positive experiences with a motor flush. I pulled the valve cover on my recently purchased BMW M50TU to rebuild the Vanos a few years back to discover the previous owner had obviously not been a fan of regular oil changes. What I found on the head look like someone had pulled the oil cap and spooned potting soil into the engine. I made the mistake of trying to scrap as much “crud” off the metal and lift it out with a shop vac, but the only way to do that well was to literally disassemble everything off the head. Deciding that just wasn’t practical, I did the best I could with a drinking straw connected to the end of the shop vac hose. The result looked good, but when all the work was complete and the engine was running again, I discovered that enough sludge material was remaining in the crankcase that it was making its way to the hydraulic lifters and periodical (but frequently) causing them to collapse and creating an engine “tick”. I decided to try the engine flush out of desperation. The can stated that the flush should be added and the car driven. I wasn’t comfortable driving the car with oil “watered down” by what in all rights seemed to be red diesel fuel; so I settled for adding the flush and just raising the engine to a fast idle until it was up to full operating temperature plus about 20 minutes of additional run time before shutting it down, draining the crankcase, and changing the oil and filter (using synthetic blend). I had one, short occasion of a lifter tick but since then, no more. The oil has been changed every 3k since and the problem seems resolved. Yes, my mistake was ever trying to scrap out the sludge in the first place and I was very lucky to have made the recovery. I would probably suggest that flushing is best left for older engines and I would probably drop the oil pan and valve covers afterward and check everything. Also, I believe that the flush itself can potentially damage engine seals and cause new oil leaks. I can’t say I would never flush another engine again (as a matter of fact, I have successfully flushed a few sludgy small engines since) but please go into it understand the possible risks. My other car has had 3k oil changes since new with no sludge now at 200,000 miles. Regular fluid changes and reasonable driving habits ARE the life of your car, IMHO.

That sucks 10 times! You're a good guy, Eric. I'm sure you'll have better luck with this engine.

I feel so bad for both of you. That stinks. I’m sure it will all work out in the end. :)

Oh man, that's unfortunate that the engine blew up so quickly after all that work :/ Hopefully the replacement engine will last as long as the Van itself. At first I thought this video was maybe made when the Fixing it Forward Odyssey was still under repairs and not given away yet.

Another way to test engine flush would be a before and after compression test. The low tension rings used in modern gas engines routinely become stuck in the piston groove. We have used BG 109 engine performance restoration for over 20 years. After using flush before and after compression tests always show improvement. We recommend BG109 to every dexos gm product we service. Many many dexos era gm vehicles suffer from extreme oil consumption.

My thought is that if you want to go over and above the regular oil change regimen. Short cycle an oil change at like 30,000 mile intervals. Change your oil and filter, then drive it normally through a tank of gas. Change it again. That should pick up a lot of the remnants naturally left over with all your other oil changes.

I have never felt the need for an engine flush. I change my oil on time like clock work. The guys at the oil change places try to upsell you on engine flushes. Clean oil=clean engine!

I flushed my engine once almost 20 years ago and it ruined the engine. I would never recommend an engine flush. The best is to use good oil and change it frequently.

I did a flush years ago on a Mazda 626. It certainly cleaned up the gunk, but that also removed the crud around my valve seals. On cold starts it would give blue smoke until the cylinders were purged, and be good until I parked it or did a high RPM pass.

Good man , thank you, i was just thinking about it flushing the engine, you change my mind, thanks again 👍

I started using synthetic Amsoil in the mid 90’s and other guys would laugh at me, I would just say try it once and you will never go back. You are right, it’s so hard to find regular oil now. It seems every oil and auto maker has decided that synthetic oil isn’t stupid after all!

Only flush an engine if you are willing to remove the oil pan a few times and change the oil and filters 4 or 5 times before driving...

I've got a 2007 CR-V and just peaking in the filler cap, I can see the buildup, I suppose from previous neglect. Only owned the vehicle for the last 20k miles, but it's closing in on 210k miles, and it runs great, in spite of the sludge and deposits. Yeah, I'm tempted to flush it, but I keep asking myself why borrow trouble with it running so well. I think I'll take Eric's advice and just keep changing it with quality oil in regular intervals. Hopefully I'll get another 50k miles out of it!

I've only done flushes to my older cars. I had a 94 camaro that i did it to. A flush, good oil and a good filter helped out. The oil would get black but it was still silky smooth.

Flushing slowly definitely seems like a better way to go.

I've found conventional 10w30 for my Saab 900 at Walmart. Maybe because lawnmowers typically use 10w30 😂

I have a '99 F150 with the 4.6 Triton V8 with over 231k miles, I've ran Motor Medic motor flush through it a couple times now prior to changing the oil, put in fresh high mileage Valvoline 10W30 along with about a half bottle of Lucas oil stabilizer, motor runs great with no leaks or smoke

Very wise advice thank you sir

I've used high mileage oil for seven years. My engine has never been cleaner. Recommend Castrol High Mileage.

Sounds like your WALLET got “Flushed”.-Sorry to hear this. Ya My 1991 Honda accord I took the vlv lid off, and had similar type solid hard-pak, all on top. So I took a shop vacuum and chiseled it off and vacuumed it out into the NOW oil soaked destroyed shop vac. Got a lot out yet really was in vain attempt to right the wrong there. I’m with ya, if YOUR UNDER VLV COVER is this way, you will send the CARBON CHUNKS thru your bearings and oil pump - BAD REALLY BAD IDEA!!! Just LEAVE IT!!! I learned in the 70’s to change oil / filter on scheduled and when did the engines ran and wore very very LONG lives.

Sorry to hear about the engine. I hope the newer one works out because you were doing a good thing with giving that away.

v70 2.4T 2001 had the pickup clogged and low oil pressure light on. I put 1Litre diesel in it and let it run on 800rpm for 3-4 houers. then emty it out and filld it up with 5L gasoline. let it sit over night and started it up for 5 sec and then 2 oil changes. it runs great now anfter almost 2 years (Y)

Must be one of those US - EU differences. I've flushed many engines, my friends done that too, never had any issues, everything worked better than before the flush, especially on diesel engines, they really love a good flush. Just get the engine warm, puth the flush in, run the engine for 10-15 minutes on idle, and make an oil and filter change, and Your TDI, JTD, or HDI will run smooth like butter.

From my all of 6 months experience at Goofy lube. I found out that all oils that are conventional weight are only in five / ten weight in 30 or 40 as in 5w_30 or 10w_40... From my experience all 5w_20 is made in a synthetic blend because of the weight property! At least that's how my boss explained it to me!

yeah Eric totally agree! I flushed my 3.8L and clogged oil pump screen, oil pressure light came on, and was clicking like mad. I ended up changing oil and filter four times straight and finally engine was running fine/no oil pressure light. wasted three good filters and oil. valves and lifters look a bit cleaner though

You can get conventional oil by various brands at Walmart or on Amazon any time. This includes high mileage conventional oil. Dollar stores usually have a few options as well.

The only thing I flush is my colon.

I think a lot of cars makers for a few years now require synthetic oil from the start. My wife's 2019 corolla and my Type R does. The 0w oils I was told are all synthetic.

Tqvm, very great and information advice

I agree with you Eric, only once I tried but with no results. I prefer same as you running good detergent oil e changing more often. Less dangerous and also you are putting the stuff in the right place. Oil in the oil pan instead of other chemicals. Greetings from Italy 🇮🇹

Never heard anything good out of an engine flush, so never done it. I change mine regularly and will let a half quart of clean oil run through before I put the drain plug back on to help get it as clean as possible.

My personal preference is to ONLY use solvents or cleaners in my fuel system. The reason is a relatively straight forward mindset: If something comes loose, it gets burned up and exhausted. Now, it could also potentially clog my catalytic converter. But frankly the risk of that happening because of some fuel cleaner or lubricant is extremely low. Any other fluids (brakes, transmission, coolant, oil, AC [which is a gas and fluid depending on pressure, but I'm including it here]) I just drain/bleed/vacuum. Because there's no benefit to descaling or removing the crud unless it has specifically created a clog, and several risks. The question of whether to flush ought to be one asked of someone who doesn't know how the components work: For anyone who understands what goes on inside.. If you find a situation where a "flush" is needed, just tear it down and rebuild it. Because you'll be doing that anyways when the flush clogs and restricts all the wrong things and breaks loose around all the gaskets that only seal because of the crud that has made up for the expansion of mating surfaces over time. As for the anecdotal "I've never had an issue" argument I often see: If you don't understand WHY a clog would impact the component or system, or HOW descaling would benefit it, then saying it hasn't backfired is not only pointless, but at the same time, likely not even true: Because your lack of understanding means that if you have had issues, you would have been unable to identify that the flush was what caused them. You either left them unresolved or changed a part thinking it was "normal wear" or something else. If you want a solid example: Watch Eric rebuild the T6 transmission, and pay attention to the number of small orifices used as oil distribution valves that are so small you can't even see them on camera. Now ask how hard it is to clog a channel that small when it's 8 inches long. Now realize there are tens of those in the transmission alone, and more in many engines. Do you think the average comment of "hasn't caused me problems" demonstrates a level of awareness to have known that oil is being starved from only one chamber inside their transmission and is the reason a very specific component wore out before others? Do they realize that it won't "break the whole engine" or "junk the transmission" but will cause a sensor or pushrod or gear or bearing to fail long before other components? No, "it hasn't caused me problems so I keep doing it" doesn't demonstrate that level of understanding at all. Meanwhile, ask yourself: What's the benefit? Might increase cooling efficiency slightly if the entire surface area is gunked up. Crud on the outer edges of a crankshaft may look dirty, but if it's not in any mating surfaces it is also not causing any problems, so it's just the appearance that improves of internals only you will see. If that bothers you, clean it while you have it apart, not by haphazardly pouring a solvent into it: Dumping a bottle of fluid doesn't qualify as a "mechanic's pride." The reality is, as stated earlier: Unless there is specifically a clog already that is causing a fault, there is no benefit to use of solvents in these enclosed systems. And even if there is a clog, ask yourself how it's supposed to work when it can't flow into and out of the area that is clogged: If it can't carry sediment away, it's not likely to do anything anyway. Just open it up and clean it out by hand in those cases. I'm not the world's most experienced mechanic. Far from. But I do practice basic reasoning daily. I think about the benefit of something by using all three types of reasoning: Deductive, Inductive, and Abductive. And since I have knowledge of how MOST systems in my vehicle are made, I can use abductive reasoning to visualize what a flush would actually do. Even in the case it does exactly what is advertised and cleans out all the junk: It provides no benefit in the vast majority of use cases, yet comes with a large number of risks that will be difficult to diagnose if they pop up.

I have an '02 Dodge Dakota Quad Cab 3.9L V6. Bought it new in December 2001, so it's going on 20 years. It only has 64k on it, but I use hi mileage synthetic due to its age. so far so good. Good oil pressure and no oil leaks. I change the oil ad filter once a year, and have to add maybe a quart between oil changes. So it seems to be doing OK on this plan.

I've had my accord 08 v6 since day one I always change my oil every two thousand miles and the is clean inside